Chapter 5 Oxidation Reduction Reactions

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Chapter 5 Oxidation Reduction Reactions"

Transcription

1 Chapter 5 Oxidation Reduction Reactions Chemistry: The Molecular Nature of Matter, 7E Jespersen/Hyslop

2 Chapter in Context Define oxidation, reduction, oxidizing agents, reducing agents, and oxidation numbers Balance oxidation/reduction reactions Explore, at the molecular level, how acids react with metals Use the activity series to predict products of reactions Learn about the reaction of oxygen with organic compounds, metals, and nonmetals Perform calculations using the stoichiometry of oxidation/reduction reactions 2

3 Oxidation-Reduction Reactions Electron transfer reactions Electrons transferred from one substance to another Originally only combustion of fuels or reactions of metal with oxygen Important class of chemical reactions that occur in all areas of chemistry and biology Also called redox reactions to emphasize that reduction and oxidation must always occur together 3

4 Oxidation Reduction Reactions Involves 2 processes: Oxidation = Loss of electrons Na Na + + e Oxidation Half-Reaction Reduction = Gain of electrons Cl 2 + 2e 2Cl Reduction Half-Reaction Net reaction: 2Na + Cl 2 2Na + + 2Cl Oxidation and reduction always occur together Can't have one without the other 4

5 Oxidation Reduction Reaction Oxidizing Agent Substance that accepts electrons Accepts electrons from another substance Substance that is reduced Cl 2 + 2e 2Cl Reducing Agent Substance that donates electrons Releases electrons to another substance Substance that is oxidized Na Na + + e 5

6 Redox Reactions Very common Batteries car, flashlight, cell phone, computer Metabolism of food Combustion Chlorine Bleach Dilute NaOCl solution Cleans through redox reaction Oxidizing agent Destroys stains by oxidizing them 6

7 Redox Reactions e.g., Fireworks displays Net: 2Mg + O 2 2MgO Oxidation: Mg Mg e Loses electrons = oxidized Reducing agent Reduction: O 2 + 4e 2O Gains electrons = reduced Oxidizing agent 7

8 Guidelines For Redox Reactions Oxidation and reduction always occur simultaneously Total number of electrons lost by one substance equals total number of electrons gained by second substance For a redox reaction to occur, something must accept electrons that are lost by another substance 8

9 Oxidation Numbers Bookkeeping Method Way to keep track of electrons Not all redox reactions contain O 2 or ions Covalent molecules and ions often involved e.g., CH 4, SO 2, MnO 4, etc. Defined by set of rules How to divide up shared electrons in compounds with covalent bonds Often whole numbers but can be fractions Change in oxidation number of element during reaction indicates redox reaction has occurred 9

10 Hierarchy of Rules for Assigning Oxidation Numbers 1. Oxidation numbers must add up to charge on molecule, formula unit or ion 2. Atoms of free elements have oxidation numbers of zero 3. Metals in Groups 1A, 2A, and Al have +1, +2, and +3 oxidation numbers, respectively 4. H and F in compounds have +1 and 1 oxidation numbers, respectively 5. Oxygen has 2 oxidation number 6. Group 7A elements have 1 oxidation number 10

11 Hierarchy of Rules for Assigning Oxidation Numbers 7. Group 6A elements have 2 oxidation number 8. Group 5A elements have 3 oxidation number 9. When there is a conflict between two of these rules or ambiguity in assigning an oxidation number, apply rule with lower oxidation number and ignore conflicting rule Oxidation State Used interchangeably with oxidation number Indicates charge on monatomic ions Iron(III) means +3 oxidation state of Fe or Fe 3+ 11

12 Ex. 1 Assigning Oxidation Number 1. Li 2 O Li (2 atoms) (+1) = +2 (Rule 3) O (1 atom) ( 2) = 2 (Rule 5) sum = 0 (Rule 1) +2 2 = 0 so the charges are balanced to zero 2. CO 2 C (1 atom) (x) = x O (2 atoms) ( 2) = 4 (Rule 5) sum = 0 (Rule 1) x 4 = 0 or x = +4 C is in +4 oxidation state 12

13 Learning Check Assign oxidation numbers to all atoms: Example 1: ClO 4 O (4 atoms) ( 2) = 8 Cl (1 atom) ( 1) = 1 (molecular ion) sum 1 (violates Rule 1) Rule 5 for oxygen comes before Rule 6 for halogens O (4 atoms) ( 2) = 8 Cl (1 atom) (x) = x sum = 1 (Rule 1) 8 + x = 1 or x = 8 1 So x = +7; Cl is oxidation state +7 13

14 Learning Check Assign oxidation states to all atoms: MgCr 2 O 7 Mg =+2; O = 2; and Cr = x (unknown) [+2] + [2x] + [7 ( 2)] = 0 2x 12 = 0 x = +3 Cr is oxidation number of +3 KMnO 4 K =+1; O = 2; so Mn = x [+1] + [x] + [4 ( 2)] = 0 x 7 = 0 x = +7 Mn is oxidation number of +7 14

15 Redefine Oxidation-Reduction in Terms of Oxidation Number A redox reaction occurs when there is a change in oxidation number Oxidation Increase in oxidation number Electron loss Reduction Decrease in oxidation number Electron gain 15

16 Using Oxidation Numbers to Recognize Redox Reactions Sometimes literal electron transfer: decrease reduction increase oxidation Cu 2+ + Zn Zn 2+ + Cu Cu: oxidation number decreases by 2 reduction Zn: oxidation number increases by 2 oxidation 16

17 Using Oxidation Numbers to Recognize Redox Reactions Reduction and oxidation can be deduced from changes in oxidation numbers O: decrease reduction C: increase oxidation CH 4 + 2O 2 CO 2 + 2H 2 O O: oxidation number decreases by 2 reduction C: oxidation number increases by 8 oxidation 17

18 Ion Electron Method Way to balance redox equations Must balance both mass and charge Write skeleton equation Only ions and molecules involved in reaction Break into two half-reactions Oxidation Reduction Balance each half-reaction separately Recombine to get balanced net ionic equation 18

19 Balancing Redox Reactions Some redox reactions are simple: e.g., Cu 2+ (aq) + Zn(s) Cu(s) + Zn 2+ (aq) Break into half-reactions Zn(s) Zn 2+ (aq) + 2e oxidation Reducing agent Cu 2+ (aq) + 2e Cu(s) reduction Oxidizing agent 19

20 Balancing Redox Reactions Zn(s) Zn 2+ (aq) + 2e Cu 2+ (aq) + 2e Cu(s) Each half-reaction is balanced for atoms oxidation reduction Same number of atoms of each type on each side Each half-reaction is balanced for charge Same sum of charges on each side Add both equations algebraically, canceling electrons NEVER have electrons in net ionic equation Cu 2+ (aq) + Zn(s) Cu(s) + Zn 2+ (aq) 20

21 Balancing Redox Equations in Aqueous Solutions Many redox reactions in aqueous solution involve H 2 O and H + or OH Balancing the equation cannot be done by inspection Need method to balance equation correctly Start with acidic solution then work to basic conditions 21

22 Ion-Electron Method Acidic Solution 1. Divide equation into two half-reactions 2. Balance atoms other than H and O 3. Balance O by adding H 2 O to side that needs O 4. Balance H by adding H + to side that needs H 5. Balance net charge by adding e 6. Make electron gain equal electron loss; then add half-reactions 7. Cancel electrons and anything that is the same on both sides 22

23 Redox in Aqueous Solution Example 2: Mix solutions of K 2 Cr 2 O 7 and FeSO 4 Dichromate ion, Cr 2 O 7, oxidizes Fe 2+ to Fe 3+ Cr 2 O 7 is reduced to form Cr 3+ Acidity of mixture decreases as H + reacts with oxygen to form water Skeletal Eqn. Cr 2 O 7 + Fe 2+ Cr 3+ + Fe 3+ 23

24 Ex. 2 Ion Electron Method Balance in Acidic Solution Cr 2 O 7 + Fe 2+ Cr 3+ + Fe Break into half-reactions Cr 2 O 7 Cr 3+ Fe 2+ Fe Balance atoms other than H and O Cr 2 O 7 2Cr 3+ Put in 2 coefficient to balance Cr Fe 2+ Fe 3+ Fe already balanced 24

25 Ex. 2 Ion-Electron Method in Acid 3. Balance O by adding H 2 O to the side that needs O Cr 2 O 7 2Cr H 2 O Left side has seven O atoms Right side has none Add seven H 2 O to right side Fe 2+ Fe 3+ No O to balance 25

26 Ex. 2 Ion-Electron Method in Acid 4. Balance H by adding H + to side that needs H 14H + + Cr 2 O 7 2Cr H 2 O Right side has fourteen H atoms Left side has none Add fourteen H + to left side Fe 2+ Fe 3+ No H to balance 26

27 Ex. 2 Ion-Electron Method in Acid 5. Balance net charge by adding electrons. 6e + 14H + + Cr 2 O 7 2Cr H 2 O Net Charge = 14(+1) +( 2) = 12 Net Charge = 2(+3)+7(0) = 6 6 electrons must be added to reactant side Fe 2+ Fe 3+ + e 1 electron must be added to product side Now both half-reactions balanced for mass and charge 27

28 Ex. 2 Ion-Electron Method in Acid 6. Make electron gain equal electron loss; then add half-reactions 6e + 14H + + Cr 2 O 7 2Cr H 2 O 6 [ Fe 2+ Fe 3+ + e ] 6e + 6Fe H + + Cr 2 O 7 6Fe Cr H 2 O + 6e 7. Cancel anything that's the same on both sides 6Fe H + + Cr 2 O 7 6Fe Cr H 2 O 28

29 Ion-Electron in Basic Solution The simplest way to balance an equation in basic solution Use steps 1 7 above, then 8. Add the same number of OH to both sides of the equation as there are H + 9. Combine H + and OH to form H 2 O 10. Cancel any H 2 O that you can from both sides 29

30 Ex. 2 Ion-Electron Method in Base Returning to our example of Cr 2 O 7 and Fe Add to both sides of equation the same number of OH as there are H +. 6Fe H + 6Fe3+ + 2Cr 3+ + Cr 2 O OH + 7H 2 O + 14 OH 9. Combine H + and OH to form H 2 O. 7 6Fe H 2 O 6Fe + Cr 2 O Cr H 2 O + 14OH 10. Cancel any H 2 O that you can 6Fe H 2 O 6Fe + Cr 2 O Cr OH 30

31 Example 3: Ion-Electron Method Balance the following equation in basic solution: MnO 4 + HSO 3 Mn 2+ + SO 4 1. Break it into half-reactions MnO 4 Mn 2+ HSO 3 SO 4 2. Balance atoms other than H and O MnO 4 Mn 2+ Balanced for Mn HSO 3 SO 4 Balanced for S 31

32 Example 3: Ion-Electron Method 3. Add H 2 O to balance O MnO 4 Mn H 2 O H 2 O + HSO 3 SO 4 4. Add H + to balance H 8H + + MnO 4 Mn H 2 O H 2 O + HSO 3 SO 4 + 3H + 32

33 Example 3: Ion-Electron Method 5. Balance net charge by adding electrons. 5e + 8H + + MnO 4 Mn H 2 O 8 (+1) + ( 1) = = +2 Add 5 e to reactant side H 2 O + HSO 3 SO 4 + 3H ( 1) = (+1) = +1 Add 2 electrons to product side + 2e 33

34 Example 3: Ion-Electron Method 6. Make electron gain equal electron loss 2 [ 5e + 8H + + MnO 4 Mn H 2 O H 2 O + HSO 3 SO 2 5 [ 4 + 3H + + 2e Must multiply Mn half-reaction by 2 Must multiply S half-reaction by 5 Now have 10 electrons on each side ] ] 34

35 Example 3: Ion-Electron Method 6. Then add the two half-reactions 10e + 16H + + 2MnO 4 2Mn H 2 O 5H 2 O + 5HSO 3 5SO H e 10e H + + 2MnO 4 + 5H 2 O + 5HSO 3 7. Cancel anything that is the same on both sides. H + + 2MnO 4 + 5HSO 3 2Mn H 2 O + 5SO 4 Balanced in acid 3 2Mn H 2 O + 5SO H e 35

36 Ex. 3 Ion-Electron Method in Base 8. Add same number of OH to both sides of equation as there are H + H + + 2MnO 4 2Mn H 2 O + + OH + 5HSO 3 5SO 4 + OH 9. Combine H + and OH to form H 2 O H 2 O + 2MnO 4 + 5HSO Cancel any H 2 O that you can 2MnO 4 + 5HSO 3 2Mn H 2 O + OH + 5SO 4 2 2Mn H 2 O + 5SO OH 36

37 Learning Check Balance each equation in the solution indicated by the skeletal reaction using the ion electron method. MnO 4 + C 2 O 4 MnO 2 + CO 3 + H + in acid 2MnO 4 + 3C 2 O 4 + 2H 2 O 2MnO 2 + 4H + + 6CO 3 ClO + VO 3 ClO 3 + V(OH) 3 + OH in base ClO + 4H 2 O + 2VO 3 ClO 3 + 2V(OH) 3 + 2OH 37

38 Acids as Oxidizing Agents Metals often react with acid Form metal ions and Molecular hydrogen gas Molecular equation Zn(s) + 2HCl(aq) H 2 (g) + ZnCl 2 (aq) Net ionic equation Zn(s) + 2H + (aq) H 2 (g) + Zn 2+ (aq) Zn is oxidized H + is reduced H + is the oxidizing reagent Zn is the reducing reagent 38

39 Oxidation of Metals by Acids Ease of oxidation process depends on metal Metals that react with HCl or H 2 SO 4 Easily oxidized by H + More active than hydrogen (H 2 ) e.g., Mg, Zn, alkali metals Mg(s) + 2H + (aq) Mg 2+ (aq) + H 2 (g) 2Na(s) + 2H + (aq) 2Na + (aq) + H 2 (g) Metals that don t react with HCl or H 2 SO 4 Not oxidized by H + Less active than H 2 e.g., Cu, Pt 39

40 Anion Determines Oxidizing Power Acids are divided into two classes: 1. Nonoxidizing Acids Anion is weaker oxidizing agent than H 3 O + Only redox reaction is 2H + + 2e H 2 or 2H 3 O + + 2e H 2 + 2H 2 O HCl(aq), HBr(aq), HI(aq) H 3 PO 4 (aq) Cold, dilute H 2 SO 4 (aq) Most organic acids (e.g., HC 2 H 3 O 2 ) 40

41 2. Oxidizing Acids Anion is stronger oxidizing agent than H 3 O + Used to react metals that are less active than H 2 No H 2 gas formed HNO 3 (aq) Concentrated Dilute Very dilute, with strong reducing agent H 2 SO 4 (aq) Hot, conc d, with strong reducing agent Hot, concentrated 41

42 Nitrate Ion as Oxidizing Agent A. Concentrated HNO 3 NO 3 more powerful oxidizing agent than H + NO 2 is product Partial reduction of N (+5 to +4) NO 3 (aq) + 2H + (aq) + e NO 2 (g) + H 2 O e.g., oxidation reduction Cu(s) + 2NO 3 (aq) + 4H + (aq) Cu 2+ (aq) + 2NO 2 (g) + 2H 2 O Reducing agent Oxidizing agent 42

43 Nitrate Ion as Oxidizing Agent B. Dilute HNO 3 NO 3 is more powerful oxidizing agent than H + NO is product Partial reduction of N (+5 to +2) NO 3 (aq) + 4H + (aq) + 3e NO(g) + 2H 2 O Used to react metals that are less active than H 2 e.g., Reaction of copper with dilute nitric acid 3Cu(s) + 8HNO 3 (dil, aq) 3Cu(NO 3 ) 2 (aq) + 2NO(g) + 4H 2 O 43

44 Reactions of Sulfuric Acid A. Hot, concentrated H 2 SO 4 Becomes potent oxidizer SO 2 is product Partial reduction of S (+6 to +4) SO 4 + 4H + + 2e SO 2 (g) + 2H 2 O e.g., Cu + 2H 2 SO 4 (hot, conc.) CuSO 4 + SO 2 + 2H 2 O B. Hot, concentrated with strong reducing agent H 2 S is product Complete reduction of S (+6 to 2) SO H + + 8e H 2 S(g) + 4H 2 O e.g., 4Zn + 5H 2 SO 4 (hot, conc.) 4ZnSO 4 + H 2 S + 4H 2 O 44

45 Redox Reactions of Metals Acids reacting with metal Special case of more general phenomena Single Replacement Reaction Reaction where one element replaces another A + BC AC + B 1. Metal A can replace metal B If A is more active metal, or 2. Nonmetal A can replace nonmetal C If A is more active than C 45

46 Single Replacement Reaction Left = Zn(s) + CuSO 4 (aq) Center = Cu 2+ (aq) reduced to Cu(s) Zn(s) oxidized to Zn 2+ (aq) Right = Cu(s) plated out on Zn bar Zn(s) + Cu 2+ (aq) Zn 2+ (aq) + Cu(s) 46

47 Single Replacement Reaction Zn 2+ ions take place of Cu 2+ ions in solution Cu atoms take place of Zn atoms in solid Cu 2+ oxidizes Zn 0 to Zn 2+ Zn 0 reduces Cu 2+ to Cu 0 More active Zn 0 replaces less active Cu 2+ Zn 0 is easier to oxidize! 47

48 Activity Series of Metals Cu less active, can't replace Zn 2+ Can't reduce Zn 2+ Cu(s) + Zn 2+ (aq) No reaction General phenomenon Metal that is more easily oxidized will displace one that is less easily oxidized from its compounds Activity Series Metals at bottom more easily oxidized (more active) than those at top This means that given metal ion will be displaced from its compounds by any metal below it in table 48

49 Activity Series of Metals 49

50 How Activity Series Generated 2H + (aq) + Sr(s) Sr 2+ (aq) + H 2 (g) H + oxidizes Sr 0 to Sr 2+ Sr 0 reduces H + to H 2 More active Sr 0 replaces less active H + Sr 0 is easier to oxidize! H 2 (g) + Sr 2+ (aq) NO REACTION! Why? H 2 less active, can't replace Sr 2+ Can't reduce Sr 2+ 50

51 Learning Check: Metal Activity Using the following observations, rank these metals from most reactive to least reactive: Cu(s) + HCl(aq) no reaction Zn(s) + 2HCl(aq) ZnCl 2 (aq) + H 2 (g) Mg(s) + ZnCl 2 (aq) MgCl 2 (aq) + Zn(s) Mg > Zn > H > Cu 51

52 Reactivity Varies by Metal Metals at very bottom of table Very strong reducing agents Very easily oxidized Na down to Cs Alkali and alkaline earth metals React with H 2 O as well as H + 2Na(s) + 2H 2 O H 2 (g) + 2NaOH(aq) 52

53 Reactivity Varies by Metal Ag slight reaction (top of activity series) not pictured 2HCl(aq) + Ag(s) 2AgCl(aq) + H 2 (g) Fe very little reactivity (near top of activity series) 2HCl(aq) + Fe(s) FeCl 2 (aq) + H 2 (g) Zn somewhat reactive (middle of activity series) 2HCl(aq) + Zn(s) ZnCl 2 (aq) + H 2 (g) Mg very reactive (bottom of activity series) 2HCl(aq) + Mg(s) MgCl 2 (aq) + H 2 (g) 53

54 Using Activity Series to Predict Reactions If M is below H Can displace H from solutions containing H + 2H + (aq) H 2 (g) If M is above H Doesn't react with nonoxidizing acids HCl, H 3 PO 4, etc. In general Metal below replaces ion above 54

55 Uses of Activity Series Predictive tool for determining outcome of single replacement reactions Given a metal (M ) and the ion of a different metal (M ' n+ ) Look at chart and draw arrow from M to M ' n+ Arrow that points up from bottom left to top right will occur Arrow that points down from top left to bottom right will NOT occur 55

56 Learning Check 2Au 3+ (aq) + 3Ca(s) Au(s) + Ca 2+ (aq) 2Au(s) + 3Ca 2+ (aq) rxn occurs NO reaction Sn(s) + Na + (aq) NO reaction Mn(s) + Co 2+ (aq) Cu(s) + H + (aq) Co(s) + Mn 2+ (aq) rxn occurs NO reaction 56

57 Reaction of Nonmetals with O 2 Many nonmetals react directly with O 2 to form nonmetal oxides Sulfur reacts with O 2 Forms SO 2 S(s) + O 2 (g) 2SO 2 (g) Nitrogen reacts with O 2 Forms various oxides NO, NO 2, N 2 O, N 2 O 3, N 2 O 4, and N 2 O 5 Dinitrogen oxide, N 2 O Laughing gas used by dentists Propellant in canned whipped cream 57

58 Oxygen as an Oxidizing Agent Oxygen reacts with many substances Combustion Rapid reaction of substance with oxygen that gives off both heat and light Hydrocarbons are important fuels Products depend on how much O 2 is available 1. Complete Combustion O 2 plentiful CO 2 and H 2 O products e.g., CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O 2C 8 H 18 (g) + 25O 2 (g) 16CO 2 (g) + 18H 2 O 58

59 Oxidation of Organic Compounds 2. Incomplete Combustion Not enough O 2 a. Limited O 2 supply CO(g) is the carbon product 2CH 4 (g) + 3O 2 (g) 2CO(g) + 4H 2 O b. Very limited O 2 C(s) is the carbon product e.g., CH 4 (g) + O 2 (g) C(s) + 2H 2 O Gives tiny black particles Soot lamp black Component of air pollution 59

60 Oxidation of Organic Compounds 3. Combustion of Organics containing O Still produce CO 2 and H 2 O Need less added O 2 C 12 H 22 O 11 (s) + 12O 2 (g) 12CO 2 (g) + 11H 2 O 4. Combustion of Organics containing S Produce SO 2 as product 2C 4 H 9 SH + 15O 2 (g) 8CO 2 (g) + 10H 2 O + 2SO 2 (g) SO 2 turns into acid rain when mixed with water SO 2 oxidized to SO 3 SO 3 reacts with H 2 O to form H 2 SO 4 60

61 Non-combustion reactions of O 2 Reactions with O 2 are not always combustion Example: luminol reaction Fe in blood catalyzes 2H 2 O 2 2H 2 O + O 2 O 2 reacts with luminol (C 8 H 5 N 3 O 2 ) C 8 H 5 N 3 O 2 + O 2 C 8 H 5 NO 4 + N 2 Energy from the reaction released as light So the appearance of light suggests blood is present 61

62 Reaction of Metals with O 2 Corrosion Direct reaction of metals with O 2 Many metals corrode or tarnish when exposed to O 2 e.g., 2Mg(s)+ O 2 (g) 2MgO(s) 4Al(s) + 3O 2 (g) 4Fe(s) + 3O 2 (g) 4Ag(s) + O 2 (g) 2Al 2 O 3 (s) 2Fe 2 O 3 (s) 2Ag 2 O(s) 62

63 Learning Check: Complete Following Reactions Aluminum metal and oxygen gas forms aluminum oxide solid 4Al(s) + 3O 2 (g) 2Al 2 O 3 (s) Solid sulfur (S 8 ) burns in oxygen gas to make gaseous sulfur trioxide S 8 (s) + 12O 2 (g) 8SO 3 (g) Copper metal is heated in oxygen to form black copper(ii) oxide solid 2Cu(s) + O 2 (g) 2CuO(s) 63

64 Stoichiometry in Redox Reactions Like any other stoichiometry problem Balance redox reaction Use stoichiometric coefficients to relate mole of one substance to moles of another Types of problems Start with mass or volume of one reactant and find mass or volume of product Perform titrations Have limiting reactant calculations Calculate percentage yields 64

65 Stoichiometry in Redox Reactions Example: How many grams of Na 2 SO 3 (126.1 g/mol) are needed to completely react with 12.4 g of K 2 Cr 2 O 7 (294.2 g/mol)? First need balanced redox equation 8H + (aq) + Cr 2 O 7 (aq) + 3SO 3 (aq) 3SO 4 (aq) + 2Cr 3+ (aq) + 4H 2 O Then do calculations 1. g K 2 Cr 2 O 7 moles K 2 Cr 2 O 7 moles Cr 2 O 7 (aq) 2. moles Cr 2 O 7 (aq) moles 3SO 4 (aq) 3. moles SO 3 (aq) moles Na 2 SO 3 g Na 2 SO 3 65

66 Ex. Redox Stoichiometry (cont.) grams K 2 Cr 2 O 7 moles K 2 Cr 2 O 7 moles Cr 2 O 7 (aq) 12.4 g K 2 Cr 2 O 7 1 mol K mol Cr 2 O 7 moles Cr 2 O 7 (aq) moles 3SO 3 (aq) mol Cr 2 O moles SO 3 (aq) moles Na 2 SO 3 g Na 2 SO g K mol Cr 2 Cr 2 Cr 2 O 2 3 mol SO 7 O O mol Cr2O 1 mol K Cr O mol SO mol Na2SO 0.126mol SO3 1 mol SO g Na 1 mol Na 2 2 SO SO g Na 2 SO 3 66

67 Redox Titrations Equivalence point reached when the number of moles of oxidizing and reducing agents have been mixed in the correct stoichiometric ratio No simple indicators to detect endpoints Three very useful oxidizing agents that change color 1. KMnO 4 : Deep purple of MnO 4 fades to almost colorless Mn 2+ (very pale pink) 2. K 2 Cr 2 O 7 : Bright yellow orange of Cr 2 O 7 changes to pale blue green of Cr IO 3 : When reduced to I 2 (s) in presence of I, forms I 3 which forms dark blue complex with starch 67

68 Example: Redox Titration I reacts with IO 3 in acidic solution to form I 2 (s). If ml of M I is needed to titrate ml of a solution containing IO 3, what is the molarity of the solution? 1. Write Unbalanced Equation I (aq) + IO 3 (aq) I 2 (s) I (aq) is oxidized to I 2 IO 3 (aq) is reduced to I 2 68

69 Ex. Redox Titration (cont) 2. Balance Equation Note: the reaction occurs in acidic solution 5 [ 2I (aq) I 2 (s) + 2e ] 2IO 3 (aq) + 12H + (aq) + 10e I 2 (s) + 6H 2 O 10I (aq) + 2IO 3 (aq) + 12H + (aq) 6I 2 (s) + 6H 2 O Not done as not lowest whole number coefficients 5I (aq) + IO 3 (aq) + 6H + (aq) 3I 2 (s) + 3H 2 O 69

70 Example: Redox Titrations Calculate mmol of I titrated mmol I 12.34mL I 7.007mmol I 1 ml I Convert to mmol of IO 3 present 1 mmol IO mmol I 5 mmol I Convert to M of IO 3 solution 1.401mmol IO 25.00mL IO 3 3 = M IO mmol IO3 70

71 Example: Ore Analysis A g sample of tin ore was dissolved in acid solution converting all the tin to tin(ii). In a titration, 8.08 ml of M KMnO4 was required to oxidize the tin(ii) to tin(iv). What was the percentage tin in the original sample? 3Sn 2+ (aq) + 2MnO 4 (aq) + 8H + (aq) 3Sn 4+ (aq) + 2MnO 2 (s) + 4H 2 O M of KMnO 4 V = mol KMnO 4 mol KMnO 4 mol Sn/mol KMnO 4 = mol Sn 2+ mol Sn 2+ MM = g Sn 2+ in sample % Sn = g Sn/g sample 100% 71

72 Example: Ore Analysis (cont.) M of KMnO 4 ml KMnO 4 = mmol KMnO M KMnO ml = mmol KMnO4 mmol KMnO 4 mmol MnO 4 mmol Sn 2+ 1 mmol MnO 0.404mmol KMnO 4 1 mmol KMnO = mmol Sn 2+ Mol Sn 2+ g/mol = g Sn in original sample 2 1 mmol Sn 0.606mmol Sn 2 1 mmol Sn = g Sn %Sn = g Sn/ g sample 100% g Sn 100 = 24.0% Sn g ore mmol Sn 2 mmol MnO 118.7mg Sn 1 mmol Sn 4 1 g 1000mg 72

Chapter 6 Oxidation-Reduction Reactions. Section 6.1 2. Which one of the statements below is true concerning an oxidation-reduction reaction?

Chapter 6 Oxidation-Reduction Reactions. Section 6.1 2. Which one of the statements below is true concerning an oxidation-reduction reaction? Chapter 6 Oxidation-Reduction Reactions 1. Oxidation is defined as a. gain of a proton b. loss of a proton c. gain of an electron! d. loss of an electron e. capture of an electron by a neutron 2. Which

More information

Chapter 11. Electrochemistry Oxidation and Reduction Reactions. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions

Chapter 11. Electrochemistry Oxidation and Reduction Reactions. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions Oxidation-Reduction Reactions Chapter 11 Electrochemistry Oxidation and Reduction Reactions An oxidation and reduction reaction occurs in both aqueous solutions and in reactions where substances are burned

More information

Oxidation-Reduction Reactions

Oxidation-Reduction Reactions Chapter 18 Oxidation-Reduction Reactions Note to teacher: You will notice that there are two different formats for the Sample Problems in the student textbook. Where appropriate, the Sample Problem contains

More information

Chapter 4: Reactions in Aqueous Solution (Sections )

Chapter 4: Reactions in Aqueous Solution (Sections ) Chapter 4: Reactions in Aqueous Solution (Sections 4.1-4.12) Chapter Goals Be able to: Classify substances as electrolytes or nonelectrolytes. Write molecular, ionic, and net ionic equations for precipitation,

More information

Ch. 9 Chemical Reactions

Ch. 9 Chemical Reactions Ch. 9 Chemical Reactions I. Intro to Reactions (p. 282 285) I II III IV V Chemical Reaction Chemical change Atoms of one or more substances (reactants) are rearranged into new substances (products) Signs

More information

Chemical Reactions in Water Ron Robertson

Chemical Reactions in Water Ron Robertson Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Properties of Compounds in Water Electrolytes and nonelectrolytes Water soluble compounds

More information

Chemical Reactions in Water

Chemical Reactions in Water Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Acids, Bases and Salts Acids dissolve in water to give H + ions. These ions attach

More information

6/27/2014. Periodic Table of the ELEMENTS. Chemical REACTIONS you should know. Brief Review for 1311 Honors Exam 2

6/27/2014. Periodic Table of the ELEMENTS. Chemical REACTIONS you should know. Brief Review for 1311 Honors Exam 2 Brief Review for 3 Honors Exam 2 Chapter 2: Periodic Table I. Metals. Representative Metals Alkali Metals Group Alkaline Earth Metals. Group 2 2. Transition Metals II. Metalloids Chapter 3: All Chapter

More information

stoichiometry = the numerical relationships between chemical amounts in a reaction.

stoichiometry = the numerical relationships between chemical amounts in a reaction. 1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse

More information

Chemistry B11 Chapter 4 Chemical reactions

Chemistry B11 Chapter 4 Chemical reactions Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl

More information

CP Chapter 11 Notes Reactions and Equations

CP Chapter 11 Notes Reactions and Equations CP Chapter 11 Notes Reactions and Equations Evidence of Chemical Reactions How can you tell a reaction has taken place? Temperature change Color change Gas/bubbles Appearance of a (precipitate) Chemical

More information

Formulae, stoichiometry and the mole concept

Formulae, stoichiometry and the mole concept 3 Formulae, stoichiometry and the mole concept Content 3.1 Symbols, Formulae and Chemical equations 3.2 Concept of Relative Mass 3.3 Mole Concept and Stoichiometry Learning Outcomes Candidates should be

More information

Goals. 1. How are chemical reactions written?

Goals. 1. How are chemical reactions written? Goals 1. How are chemical reactions written? Given the identities of reactants and products, be able to write a balanced chemical equation or net ionic equation. 2. How are chemical reactions of ionic

More information

Chemistry AS90171 Describe chemical reactions

Chemistry AS90171 Describe chemical reactions Chemistry AS90171 Describe chemical reactions This achievement standard involves the description of chemical reactions, including the carrying out of calculations. Achievement Merit Excellence Describe

More information

Chapter 8 - Chemical Equations and Reactions

Chapter 8 - Chemical Equations and Reactions Chapter 8 - Chemical Equations and Reactions 8-1 Describing Chemical Reactions I. Introduction A. Reactants 1. Original substances entering into a chemical rxn B. Products 1. The resulting substances from

More information

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents 1 Chapter 9 Chemical Quantities 2 Chapter 9 Table of Contents 9.1 Information Given by Chemical Equations 9.2 9.3 Copyright Cengage Learning. All rights reserved 2 3 Section 9.1 Information Given by Chemical

More information

Mole - Mass Relationships in Chemical Systems

Mole - Mass Relationships in Chemical Systems Chapter 3: Stoichiometry Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing Chemical Equations 3.4 Calculating the Amounts

More information

MOLE CONVERSION PROBLEMS. 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles]

MOLE CONVERSION PROBLEMS. 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles] MOLE CONVERSION PROBLEMS 1. What is the molar mass of MgO? [40.31 g/mol] 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles] 3. How many moles are present in 2.5 x 10 23 molecules of CH

More information

Chemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles:

Chemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles: Quantities of Reactants and Products CHAPTER 3 Chemical Reactions Stoichiometry Application of The Law of Conservation of Matter Chemical book-keeping Chemical Equations Chemical equations: Describe proportions

More information

Molecular Formula: Example

Molecular Formula: Example Molecular Formula: Example A compound is found to contain 85.63% C and 14.37% H by mass. In another experiment its molar mass is found to be 56.1 g/mol. What is its molecular formula? 1 CHAPTER 3 Chemical

More information

1. P 2 O 5 2. P 5 O 2 3. P 10 O 4 4. P 4 O 10

1. P 2 O 5 2. P 5 O 2 3. P 10 O 4 4. P 4 O 10 Teacher: Mr. gerraputa Print Close Name: 1. A chemical formula is an expression used to represent 1. mixtures, only 3. compounds, only 2. elements, only 4. compounds and elements 2. What is the total number

More information

Georgia Institute of Technology CHEM 1310 Fall Semester 2009 Recitation Assignment! Fundamental Principles and Terminology

Georgia Institute of Technology CHEM 1310 Fall Semester 2009 Recitation Assignment! Fundamental Principles and Terminology The Fundamentals and Stoichiometry Recitation Worksheet Week of 25 August 2008. Fundamental Principles and Terminology Avogadro s Number: Used to represent the amount of a given atom as a basis for comparison

More information

Redox and Electrochemistry

Redox and Electrochemistry Name: Thursday, May 08, 2008 Redox and Electrochemistry 1. A diagram of a chemical cell and an equation are shown below. When the switch is closed, electrons will flow from 1. the Pb(s) to the Cu(s) 2+

More information

4. Aluminum chloride is 20.2% aluminum by mass. Calculate the mass of aluminum in a 35.0 gram sample of aluminum chloride.

4. Aluminum chloride is 20.2% aluminum by mass. Calculate the mass of aluminum in a 35.0 gram sample of aluminum chloride. 1. Calculate the molecular mass of table sugar sucrose (C 12 H 22 O 11 ). A. 342.30 amu C. 320.05 amu B. 160.03 amu D. 171.15 amu 2. How many oxygen atoms are in 34.5 g of NaNO 3? A. 2.34 10 23 atoms C.

More information

Chemical Reactions. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 4

Chemical Reactions. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 4 Chemistry 100 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 4 Chemical Reactions Chemical Reactions In a chemical reaction, one set of chemical

More information

Name Class Date. Chapter: Chemical Equations and Reactions

Name Class Date. Chapter: Chemical Equations and Reactions Assessment Chapter Test B Chapter: Chemical Equations and Reactions PART I In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question

More information

Metals Topic Test. Part 1: Multiple Choice Choose the best alternative and indicate your response on the answer sheet

Metals Topic Test. Part 1: Multiple Choice Choose the best alternative and indicate your response on the answer sheet Metals Topic Test Part 1: Multiple Choice Choose the best alternative and indicate your response on the answer sheet 1. The chemical equation for the reaction between aluminium and oxygen is: 4Al (s) +

More information

Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations

Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations CHE11 Chapter Chapter Stoichiometry: Calculations with Chemical Formulas and Equations 1. When the following equation is balanced, the coefficients are. NH (g) + O (g) NO (g) + H O (g) (a). 1, 1, 1, 1

More information

EXPERIMENT 8: Activity Series (Single Displacement Reactions)

EXPERIMENT 8: Activity Series (Single Displacement Reactions) EPERIMENT 8: Activity Series (Single Displacement Reactions) PURPOSE a) Reactions of metals with acids and salt solutions b) Determine the activity of metals c) Write a balanced molecular equation, complete

More information

Reactions. Balancing Chemical Equations uses Law of conservation of mass: matter cannot be lost in any chemical reaction

Reactions. Balancing Chemical Equations uses Law of conservation of mass: matter cannot be lost in any chemical reaction Reactions Chapter 8 Combustion Decomposition Combination Chapter 9 Aqueous Reactions Exchange reactions (Metathesis) Formation of a precipitate Formation of a gas Formation of a week or nonelectrolyte

More information

Do Now CHEMICAL REACTIONS. Chemical Reaction. chemical reaction. Chemical Equations. Evidence

Do Now CHEMICAL REACTIONS. Chemical Reaction. chemical reaction. Chemical Equations. Evidence Do Now CHEMICAL REACTIONS What are some signs that a chemical change may have taken place? Where are the reactants and products in a reaction? What do they represent? Describe the law of conservation of

More information

Chapter 5. Chemical Reactions and Equations. Introduction. Chapter 5 Topics. 5.1 What is a Chemical Reaction

Chapter 5. Chemical Reactions and Equations. Introduction. Chapter 5 Topics. 5.1 What is a Chemical Reaction Introduction Chapter 5 Chemical Reactions and Equations Chemical reactions occur all around us. How do we make sense of these changes? What patterns can we find? 1 2 Copyright The McGraw-Hill Companies,

More information

Inorganic Chemistry Writing (Net Ionic) Equations for Various Reactions

Inorganic Chemistry Writing (Net Ionic) Equations for Various Reactions -1- Inorganic Chemistry Writing (Net Ionic) Equations for Various Reactions On the AP examination you will encounter a question in which you will be required to write net ionic equations for various reactions.

More information

The formation of a gas is evidence of. 1. A chemical change. 2. A physical change. 3. No change in energy 4. Both (1) and (2)

The formation of a gas is evidence of. 1. A chemical change. 2. A physical change. 3. No change in energy 4. Both (1) and (2) Chapter 8 Review The formation of a gas is evidence of 1. A chemical change. 2. A physical change. 3. No change in energy 4. Both (1) and (2) The formation of a gas is evidence of 1. A chemical change.

More information

How Many Cookies Can I Make? You can make cookies until you run out of one of the ingredients Once you run out of sugar, you will stop making cookies

How Many Cookies Can I Make? You can make cookies until you run out of one of the ingredients Once you run out of sugar, you will stop making cookies Limi$ng reactants How Many Cookies Can I Make? You can make cookies until you run out of one of the ingredients Once you run out of sugar, you will stop making cookies How Many Cookies Can I Make? In this

More information

Worksheet # 11. 4. When heated, nickel (II) carbonate undergoes a decomposition reaction. Write a balanced equation to describe this reaction

Worksheet # 11. 4. When heated, nickel (II) carbonate undergoes a decomposition reaction. Write a balanced equation to describe this reaction Worksheet # 11 1. A solution of sodium chloride is mixed with a solution of lead (II) nitrate. A precipitate of lead (II) chloride results, leaving a solution of sodium nitrated. Determine the class of

More information

Chapter 12: Oxidation and Reduction.

Chapter 12: Oxidation and Reduction. 207 Oxidation- reduction (redox) reactions Chapter 12: Oxidation and Reduction. At different times, oxidation and reduction (redox) have had different, but complimentary, definitions. Compare the following

More information

Chapter 5, Calculations and the Chemical Equation

Chapter 5, Calculations and the Chemical Equation 1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles

More information

Chapter 3. Stoichiometry of Formulas and Equations

Chapter 3. Stoichiometry of Formulas and Equations Chapter 3 Stoichiometry of Formulas and Equations Chapter 3 Outline: Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing

More information

Chemical Equations & Stoichiometry

Chemical Equations & Stoichiometry Chemical Equations & Stoichiometry Chapter Goals Balance equations for simple chemical reactions. Perform stoichiometry calculations using balanced chemical equations. Understand the meaning of the term

More information

Name Class Date. Chapter: Chemical Equations and Reactions

Name Class Date. Chapter: Chemical Equations and Reactions Assessment Chapter Test A Chapter: Chemical Equations and Reactions In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. You

More information

1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams?

1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? Name: Tuesday, May 20, 2008 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance

More information

Chapter 7 Chemical Reactions. Chemical & Physical Changes

Chapter 7 Chemical Reactions. Chemical & Physical Changes Chapter 7 Chemical Reactions Chemical & Physical Changes In a physical change, the chemical composition of the substance remains constant. Examples of physical changes are the melting of ice or the boiling

More information

Chemical Reactions. Chemical Arithmetic

Chemical Reactions. Chemical Arithmetic Chemical Reactions Chapter 6 Chemical Arithmetic Balancing Equations The mole Gram - mole conversions Mole - mole relationships in chemical equations Mass relationships in chemical equations Per cent yeilds

More information

Oxidation-Reduction Reactions

Oxidation-Reduction Reactions CHAPTER 19 REVIEW Oxidation-Reduction Reactions SECTION 1 SHORT ANSWER Answer the following questions in the space provided. 1. All the following equations involve redox reactions except (a) CaO H 2 O

More information

Moles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe:

Moles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe: Like a recipe: Balancing Eqns Reactants Products 2H 2 (g) + O 2 (g) 2H 2 O(l) coefficients subscripts Balancing Eqns Balancing Symbols (s) (l) (aq) (g) or Yields or Produces solid liquid (pure liquid)

More information

Chapter 3 Stoichiometry

Chapter 3 Stoichiometry Chapter 3 Stoichiometry 3-1 Chapter 3 Stoichiometry In This Chapter As you have learned in previous chapters, much of chemistry involves using macroscopic measurements to deduce what happens between atoms

More information

c. PCl 3 (l) + 3H 2 O(l) H 3 PO 3 (l) + 3HCl(g)

c. PCl 3 (l) + 3H 2 O(l) H 3 PO 3 (l) + 3HCl(g) Chapter 9 Chemical Quantities 1. Although we define mass as the amount of matter in a substance, the units in which we measure mass are a human invention. Atoms and molecules react on an individual particleby-particle

More information

Chapter 5 Chemical Quantities and Reactions

Chapter 5 Chemical Quantities and Reactions Chapter 5 Chemical Quantities and Reactions 1 Avogadro's Number Small particles such as atoms, molecules, and ions are counted using the mole. 1 mole = 6.02 x 10 23 items Avogadro s number 602 000 000

More information

CHAPTER 4. AQUEOUS REACTION CHEMISTRY

CHAPTER 4. AQUEOUS REACTION CHEMISTRY CAPTER. AQUEOUS REACTION CEMISTRY solution - homogeneous mixture of or more substances; uniform distribution of particles and same properties throughout. A solution is composed of a solute dissolved in

More information

Skeleton Equations equations describing a reaction using formulas. HCl(aq) + Zn(s) ZnCl 2 (aq) + H 2 (g)

Skeleton Equations equations describing a reaction using formulas. HCl(aq) + Zn(s) ZnCl 2 (aq) + H 2 (g) 10.1 Reactions and Equations Evidence of Chemical Reactions Chemical Reaction a process in which one or more substances are converted into new substances with different physical and chemical properties.

More information

Oxidation-Reduction Reactions

Oxidation-Reduction Reactions Oxidation-Reduction Reactions What is an Oxidation-Reduction, or Redox, reaction? Oxidation-reduction reactions, or redox reactions, are technically defined as any chemical reaction in which the oxidation

More information

AP Chemistry. Unit #3. Chapter 3 Zumdahl

AP Chemistry. Unit #3. Chapter 3 Zumdahl AP Chemistry Unit #3 Chapter 3 Zumdahl Stoichiometry C6H12O6 + 6 O2 6 CO2 + 6 H2O Students should be able to: Calculate the atomic weight (average atomic mass) of an element from the relative abundances

More information

Formulas, Equations and Moles

Formulas, Equations and Moles Chapter 3 Formulas, Equations and Moles Interpreting Chemical Equations You can interpret a balanced chemical equation in many ways. On a microscopic level, two molecules of H 2 react with one molecule

More information

Chapter 3: Stoichiometry

Chapter 3: Stoichiometry Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Avogadro's Number, molar mass and converting between mass and moles (REVIEW). 2. empirical formulas from analysis.

More information

C u ( O H ) 2. N i ( N O 3 ) 2. N a m e C a t i o n Cation A n i o n A n i o n

C u ( O H ) 2. N i ( N O 3 ) 2. N a m e C a t i o n Cation A n i o n A n i o n Name Exam 3 Page 1 AQUEUS SLUTINS 1. (8 points) Names, formulas, and water-solubility of compounds. N a m e F o r m u l a Soluble in Water? Ammonium chloride N H 4 C l y e s C u ( H N i ( N 3 Iron(III)

More information

Types of Chemical Reactions (rxns.)

Types of Chemical Reactions (rxns.) Types of Chemical Reactions (rxns.) Chemical reactions occur when bonds (between the electrons of atoms) are formed or broken Chemical reactions involve l changes in the chemical composition of matter

More information

Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions.

Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions. Aqueous Solutions and Solution Stoichiometry Water is the dissolving medium, or solvent. Some Properties of Water Water is bent or V-shaped. The O-H bonds are covalent. Water is a polar molecule. Hydration

More information

Chemical Reactions Vocabulary

Chemical Reactions Vocabulary Chemical Reactions Vocabulary Chemical Reaction Chemical Equation Process in which the physical and chemical properties of the original substances change as a new substance with different physical and

More information

Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses

Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro

More information

Chemical Reactions and Equations. Chapter 8

Chemical Reactions and Equations. Chapter 8 Chemical Reactions and Equations Chapter 8 Describing Chemical Reactions A chemical reaction is the process by which one or more substances are changed into different substances Reactants Products When

More information

Subscripts and Coefficients Give Different Information

Subscripts and Coefficients Give Different Information Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Chemical equations (Balancing REVIEW) 2. Some simple patterns of reactivity 3. Formula weights (REVIEW) 4. Avogadro's

More information

Identify the letter of the choice that best completes the statement or answers the question.

Identify the letter of the choice that best completes the statement or answers the question. Chemistry Test - Chapter 10 Chemical Equations Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. When balancing a chemical equation, insert

More information

IB Chemistry. DP Chemistry Review

IB Chemistry. DP Chemistry Review DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount

More information

Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry

Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry AP Chemistry A. Allan Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry 4.1 Water, the Common Solvent A. Structure of water 1. Oxygen's electronegativity is high (3.5) and hydrogen's

More information

IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.

IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily. The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole

More information

Chapter 8 Review and Study Guide

Chapter 8 Review and Study Guide Name: Class: Date: Chapter 8 Review and Study Guide Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Knowledge about what products are produced in a chemical

More information

Ch 8 Notes: Chemical Equations and Reactions

Ch 8 Notes: Chemical Equations and Reactions Name: Ch 8 Notes: Chemical Equations and Reactions I. Chemical Equations A properly written chemical equation can summarize any chemical change. The following requirements will help you write and read

More information

1332 CHAPTER 18 Sample Questions

1332 CHAPTER 18 Sample Questions 1332 CHAPTER 18 Sample Questions Couple E 0 Couple E 0 Br 2 (l) + 2e 2Br (aq) +1.06 V AuCl 4 + 3e Au + 4Cl +1.00 V Ag + + e Ag +0.80 V Hg 2+ 2 + 2e 2 Hg +0.79 V Fe 3+ (aq) + e Fe 2+ (aq) +0.77 V Cu 2+

More information

Stoichiometry Chapter 9 Assignment & Problem Set

Stoichiometry Chapter 9 Assignment & Problem Set Stoichiometry Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Stoichiometry 2 Study Guide: Things You Must Know Vocabulary (know the definition

More information

Calculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu

Calculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu Calculations and Chemical Equations Atomic mass: Mass of an atom of an element, expressed in atomic mass units Atomic mass unit (amu): 1.661 x 10-24 g Atomic weight: Average mass of all isotopes of a given

More information

Chemistry 1000 A Fall 2004 Answers to Problem Set #3

Chemistry 1000 A Fall 2004 Answers to Problem Set #3 Chemistry 1000 A Fall 2004 Answers to Problem Set #3 1. Balance the following equations, and name the reaction products: (a) UO 2 (s) + 4 HF(l) UF 4 (s) + 2 H 2 O(l): Uranium tetrafluoride and water (dihydrogen

More information

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4)

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4) Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1 1. 2. 3. 4. 5. 6. Question What is a symbolic representation of a chemical reaction? What 3 things (values) is a mole of a chemical

More information

Chapter 3 Calculation with Chemical Formulas and Equations

Chapter 3 Calculation with Chemical Formulas and Equations Chapter 3 Calculation with Chemical Formulas and Equations Practical Applications of Chemistry Determining chemical formula of a substance Predicting the amount of substances consumed during a reaction

More information

Part I: Parts and Meaning of a Chemical Equation:

Part I: Parts and Meaning of a Chemical Equation: Chemical Equations Name: Period: Date: Part I: Parts and Meaning of a Chemical Equation: 1) = process by which one or more substances are changed into one or more different substances (atoms are rearranged)

More information

CHEM 101 HOUR EXAM II 13-OCT-98. Directions: show all work for each question only on its corresponding numbered blue book page.

CHEM 101 HOUR EXAM II 13-OCT-98. Directions: show all work for each question only on its corresponding numbered blue book page. CHEM 101 HOUR EXAM II 13-OCT-98 Directions: show all work for each question only on its corresponding numbered blue book page. 1. Write a balanced net ionic equation for each reaction or process shown:

More information

4/16/13 Objective Review ionic and covalent bonding Identify the signs of a chemical reaction and discuss chemical equations 4/15/13

4/16/13 Objective Review ionic and covalent bonding Identify the signs of a chemical reaction and discuss chemical equations 4/15/13 4/15/13 Illustrate bonding Describe the signs of a chemical reaction and discuss chemical equations Find the charge of the ions below: (int: Ignore the neutrons and compare p and e) 1.5 protons, 6 electrons,

More information

11.2 Types of Chemical Reactions> Chapter 11 Chemical Reactions Types of Chemical Reactions Describing Chemical Reactions

11.2 Types of Chemical Reactions> Chapter 11 Chemical Reactions Types of Chemical Reactions Describing Chemical Reactions Chapter 11 Chemical 11.1 Describing Chemical 11.2 Types of Chemical 11.3 in Aqueous Solution 1 CHEMISTRY & YOU What happens to the wax when you burn a candle? When you burn a candle, a chemical reaction

More information

Chapter 3. Stoichiometry: Ratios of Combination. Insert picture from First page of chapter. Copyright McGraw-Hill 2009 1

Chapter 3. Stoichiometry: Ratios of Combination. Insert picture from First page of chapter. Copyright McGraw-Hill 2009 1 Chapter 3 Insert picture from First page of chapter Stoichiometry: Ratios of Combination Copyright McGraw-Hill 2009 1 3.1 Molecular and Formula Masses Molecular mass - (molecular weight) The mass in amu

More information

Worked solutions to student book questions Chapter 16 Redox chemistry and corrosion

Worked solutions to student book questions Chapter 16 Redox chemistry and corrosion Q1. Identify each of the following half equations as involving either oxidation or reduction: a Na(s) Na + (aq) + e b Cl 2 (g) + 2e 2Cl (aq) c S(s) + 2e S 2 (aq) d Zn(s) Zn 2+ (aq) + 2e A1. a oxidation

More information

3. How many moles of KCl and O 2 are formed from the decomposition of 6 moles of KClO 3?

3. How many moles of KCl and O 2 are formed from the decomposition of 6 moles of KClO 3? What coefficients mean: 2 Na + Cl 2 2NaCl 2 Na 1 Cl 2 2NaCl 4 Na 2 Na + Cl 2 4Cl 2 6 moles Na 2NaCl 10 atoms Na ONLY WORKS FOR MOLES, MOLECULES, ATOMS 1. How many moles of H 2 and O 2 must react to form

More information

Chemical Equations and Calculations

Chemical Equations and Calculations Chemical Equations and Calculations A chemical equation is a shorthand way of indicating what is going on in a chemical reaction. We could do it the long way Two molecules of Hydrogen gas react with one

More information

Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent

Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Water a polar solvent: dissolves most ionic compounds as well as many molecular compounds Aqueous solution:

More information

CHAPTER 8 Chemical Equations and Reactions

CHAPTER 8 Chemical Equations and Reactions CHAPTER 8 Chemical Equations and Reactions SECTION 1 Describing Chemical Reactions OBJECTIVES 1. List three observations that suggest that a chemical reaction has taken place. 2. List three requirements

More information

2. Write the chemical formula(s) of the product(s) and balance the following spontaneous reactions.

2. Write the chemical formula(s) of the product(s) and balance the following spontaneous reactions. 1. Using the Activity Series on the Useful Information pages of the exam write the chemical formula(s) of the product(s) and balance the following reactions. Identify all products phases as either (g)as,

More information

EXPERIMENT 7 Reaction Stoichiometry and Percent Yield

EXPERIMENT 7 Reaction Stoichiometry and Percent Yield EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry

More information

Stoichiometry (greek): Stoicheion element, metry to measure

Stoichiometry (greek): Stoicheion element, metry to measure Stoichiometry Stoichiometry (greek): Stoicheion element, metry to measure Balanced Chemical equation: Skills Tells Ex. formula writing balancing equations substances involved in the chemical rxn relationship

More information

Chemical calculations

Chemical calculations Chemical calculations Stoichiometry refers to the quantities of material which react according to a balanced chemical equation. Compounds are formed when atoms combine in fixed proportions. E.g. 2Mg +

More information

1. Balance the following equation. What is the sum of the coefficients of the reactants and products?

1. Balance the following equation. What is the sum of the coefficients of the reactants and products? 1. Balance the following equation. What is the sum of the coefficients of the reactants and products? 1 Fe 2 O 3 (s) + _3 C(s) 2 Fe(s) + _3 CO(g) a) 5 b) 6 c) 7 d) 8 e) 9 2. Which of the following equations

More information

Chemical Equations. Chemical Equations. Chemical reactions describe processes involving chemical change

Chemical Equations. Chemical Equations. Chemical reactions describe processes involving chemical change Chemical Reactions Chemical Equations Chemical reactions describe processes involving chemical change The chemical change involves rearranging matter Converting one or more pure substances into new pure

More information

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points)

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points) CHEMISTRY 123-07 Midterm #1 Answer key October 14, 2010 Statistics: Average: 74 p (74%); Highest: 97 p (95%); Lowest: 33 p (33%) Number of students performing at or above average: 67 (57%) Number of students

More information

THREE CHEMICAL REACTIONS

THREE CHEMICAL REACTIONS THREE CHEMICAL REACTIONS 1 NOTE: You are required to view the podcast entitled Decanting and Suction Filtration before coming to lab this week. Go to http://podcast.montgomerycollege.edu/podcast.php?rcdid=172

More information

Stoichiometry Review. 1. Given the formula for a compound: 4. What is the chemical formula for zinc carbonate?

Stoichiometry Review. 1. Given the formula for a compound: 4. What is the chemical formula for zinc carbonate? 1. Given the formula for a compound: 4. What is the chemical formula for zinc carbonate? Which molecular formula and empirical formula represent this compound? A) C2HNO2 and CHNO B) C2HNO2 and C2HNO2 C)

More information

Stoichiometry and Aqueous Reactions (Chapter 4)

Stoichiometry and Aqueous Reactions (Chapter 4) Stoichiometry and Aqueous Reactions (Chapter 4) Chemical Equations 1. Balancing Chemical Equations (from Chapter 3) Adjust coefficients to get equal numbers of each kind of element on both sides of arrow.

More information

Appendix D. Reaction Stoichiometry D.1 INTRODUCTION

Appendix D. Reaction Stoichiometry D.1 INTRODUCTION Appendix D Reaction Stoichiometry D.1 INTRODUCTION In Appendix A, the stoichiometry of elements and compounds was presented. There, the relationships among grams, moles and number of atoms and molecules

More information

Experiment 5: Studying Chemical Reactions

Experiment 5: Studying Chemical Reactions 1 Experiment 5: Studying Chemical Reactions When a chemical reaction occurs, substances called reactants are transformed into different substances called products that may have different appearances and

More information

Instructions Answer all questions in the spaces provided. Do all rough work in this book. Cross through any work you do not want to be marked.

Instructions Answer all questions in the spaces provided. Do all rough work in this book. Cross through any work you do not want to be marked. GCSE CHEMISTRY Higher Tier Chemistry 1H H Specimen 2018 Time allowed: 1 hour 45 minutes Materials For this paper you must have: a ruler a calculator the periodic table (enclosed). Instructions Answer all

More information

OXIDATION NUMBERS (Section 4.4)

OXIDATION NUMBERS (Section 4.4) 1 OXIDATION NUMBERS (Section 4.4) Oxidation number is the charge of an atom in a molecule if all the bonding is considered ionic. Oxidation number is different from formal charge. Using oxidation numbers

More information

Stoichiometry. Unit Outline

Stoichiometry. Unit Outline 3 Stoichiometry Unit Outline 3.1 The Mole and Molar Mass 3.2 Stoichiometry and Compound Formulas 3.3 Stoichiometry and Chemical Reactions 3.4 Stoichiometry and Limiting Reactants 3.5 Chemical Analysis

More information

21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11

21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11 21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11 1. Consider the equation: 2Ca(s) + O 2 (g) 2CaO(s) Which of the following statements are correct? (1) Calcium and oxygen are reactants.

More information