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

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Preston McKenzie
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1 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 6 moles of H 2 O? 3. How many moles of KCl and O 2 are formed from the decomposition of 6 moles of KClO 3? 2. How many moles of water must react with 0.25 moles of CaC 2? CaC 2 + 2H 2 O C 2 H 2 + Ca(OH) 2 4. How many grams of oxygen are needed to react with 4.41 g of Li to form Li 2 O? (Ans: 5.08 g) 1

2 5. How many grams of oxygen are needed to react with 17.5 g of Al? (Ans: 15.6) Al + O 2 Al 2 O 3 6. How many grams of oxygen will react with 25.0 g of C 2 H 6? (Ans: 93.3 g) C 2 H 6 + O 2 CO 2 + H 2 O 7. How many grams of P 4 and O 2 are needed to make 3.62 g of P 2 O 5? (Ans: 1.58 g, 2.04 g) P 4 + O 2 P 2 O 5 Calculate the mass of aluminum required to produce g of iron. Also calculate the formula units of Fe 2 O 3 that are used in the process. What mass of oxygen is needed to react with 16.7 g of iron to form Iron(III)oxide? How many molecules of O 2 are used? Al + Fe 2 O 3 Al 2 O 3 + Fe 4Fe + 3O 2 2Fe 2 O g Al, 4.05 X Ans: 7.18 g, 1.35 X molecules KClO 3 decomposes into potassium chloride and oxygen. If you start with 50.0 grams of KClO 3, calculate the mass of each product that forms. Lead(II)Nitrate reacts with potassium iodide to form potassium nitrate and lead(ii)iodide. a. Write the balanced reaction b. What type of reaction is this? c. Calculate the grams of potassium nitrate formed from the reaction of 18.0 g of lead(ii)nitrate. (11.0 g) d. Calculate atoms of iodine in the lead(ii) iodide. (6.54 X atoms I) 2

3 The following problems refer to FeSO 4 a. Is the compound ionic or molecular? b. Write the proper name of the compound. c. Calculate the oxidation state of the sulfur in the SO 4 2- ion. d. Write the reaction that would occur between FeSO 4 and NaCl. e. Calculate how many grams of NaCl are needed to react with 15.4 grams of FeSO 4. (11.9 g) 1. Sandwich analogy: 14 slices of bread 4 pieces of turkey (low fat) Maximum # of sandwiches? Limiting Reactant 2. Limiting Reactant Totally consumed in a reaction. No leftovers (CuSO 4 and Al wire demo, heat soln first) 1. How many grams of H 2 SO 4 can be formed from the rxn of 5.00 moles of SO 3 and 2.00 moles of H 2 O? 2. How many grams of H 2 O can be formed from the rxn of 6.00 moles of H 2 and 4.00 moles of O 2? SO 3 + H 2 O H 2 SO 4 O 2 + H 2 H 2 O (Ans: 196 g) 3. How many grams of NaCl can be formed from the reaction of mol of Na and mol of Cl 2? (Ans: 11.7 g) 4. How many grams of Ag can be formed from the rxn of 2.00 g of Zn and 2.50 g of silver nitrate? How much excess reactant remains? Zn + AgNO 3 Ag + Zn(NO 3 ) 2 2Na + Cl 2 2NaCl (Ans: 1.59 g Ag, 1.52 g xs zinc) 3

4 5. How many grams of Ag 2 S can be formed from the rxn of 15.6 g of Ag and 2.97 g of H 2 S? (Assume O 2 is in excess) 6. How many grams of CO 2 can be formed from the rxn of 40.0 g of CH 3 OH and 46.0 g of O 2? 4Ag + 2H 2 S + O 2 2Ag 2 S + 2H 2 O 2CH 3 OH + 3O 2 2CO 2 + 4H 2 O (Ans: 18.0 g) (Ans: 42.2 g) 7. How many grams of Ba 3 (PO 4 ) 2 can be formed from the rxn of 3.50 g of Na 3 PO 4 and 6.40 g of Ba(NO 3 ) 2? (Ans: 4.92 g) Na 3 PO 4 + Ba(NO 3 ) 2 Ba 3 (PO 4 ) 2 + NaNO 3 1. Calculate the mass of aluminum required to produce g of iron. Also calculate the formula units of Fe 2 O 3 that are used in the process. (363 g Al, 4.05 X form. units) Al + Fe 2 O 3 Al 2 O 3 + Fe 2. If grams of NaOH is reacted with grams of H 3 PO 4, 3 NaOH(aq) + H 3 PO 4 (aq) Na 3 PO 4 (aq) + 3 H 2 O(l) a. How many grams of Na 3 PO 4 are formed? (48.7 g) b. How many grams of the excess reactant remains when the reaction is complete? (1.67 g) Formula: Percent Yield 1. What is the % yield if you start with grams of C and obtain 1.49 g of H 2 gas? Actual Yield Theoretical Yield X 100 = % Yield C + H 2 O CO + H 2 (Ans: 89.2%) 4

5 2. Carbon was heated strongly in sulfur(s 8 ) to form carbon disulfide. What is the percent yield if you start with g of sulfur and collect 12.5 g of CS 2? 4C + S 8 4CS 2 Calculate the percent yield of the following reaction if 60.0 grams of CaCO 3 is heated to give 15.0 grams of CaO? CaCO 3 CaO + CO 2 (Ans: 78.0%) [44%] The percent yield of the following equation is 55%. SO 3 (g) + H 2 O(l) H 2 SO 4 (aq) a. Calculate the theoretical yield of H 2 SO 4 when grams of SO 3 are combined with excess water? (196 g) b. Calculate the actual yield (108 g) Molarity 1. Molarity = measure of the concentration of a solution 2. Molarity = moles/liter Similar to Density = g/l 5

6 3. Which is more concentrated? 1 M HCl 3 M HCl Molarity 1. What is the molarity of a soln that contains g of H 2 SO 4 in enough water to make ml of solution? (Ans: 2.00 M) 2. What is the molarity of a soln made by dissolving 23.4 g of Na 2 SO 4 in enough water to make 125 ml of solution? (Ans: 1.32 M) 3. What mass of HCl is present in 155 ml of M HCl? (Ans: 3.06 g) 5. What volume of M NaOH is needed to provide moles? (Ans: 6.44 ml) 4. How many grams of NaOH are in 5.00 ml of M NaOH? (Ans: g) 6. What volume of M HCl is needed to provide g of HCl?(Ans: 25 ml) Mixing From a Solid How would you prepare ml of M Na 2 SO 4? 1. Mixing from a solid 6

7 1. Mass 24.9 g of Na 2 SO Dissolve in a small volume of water. 3. Dilute to ml. 3. Write directions for the preparation of ml of M KMnO 4 (10.5g) 4. Write directions for the preparation of ml of M NaOH ( g) 1. Mass 10.5 g of KMnO Dissolve in a small volume of water. 3. Dilute to ml. 1. Mass g of NaOH 2. Dissolve in a small volume of water. 3. Dilute to ml. Diluting from a Solution 1. Dilution Formula: M 1 V 1 = M 2 V 2 2. Used when you are starting with a more concentrated soln. (Grape juice concentrate, Coke syrup) 1. What is the molarity of a soln of KCl that is prepared by diluting 855 ml of M soln to a volume of 1.25 L? (Ans: M) How would you prepare ml of M NaOH from a 2.72 L bottle of M NaOH? 2. You have a 3.00 L bottle of 11.3 M HCl. What volume of it must be diluted to make 1.00 L of M HCl? (Ans: 49.1 ml) 7

The following questions refer to a 0.0987 M solution of NaNO 3. a. Calculate how many grams of NaNO 3 are present in 50.0 ml of the solution. (0.419 g) b.

8 The following questions refer to a M solution of NaNO 3. a. Calculate how many grams of NaNO 3 are present in 50.0 ml of the solution. (0.419 g) b. Calculate the volume of the solution required to provide grams of NaNO 3. (22.4 ml) c. State how you would prepare ml of the solution starting with solid NaNO 3. (4.19 g) d. State how you would prepare ml of the solution starting with a large 3-L bottle of 2.00 M NaNO 3 (aq) (24.7 ml) c. 1) Mass 4.19 g of NaNO 3 2) Place in a small volume of water to dissolve 3) Dilute to 500 ml d. 1) Measure 24.7 ml of 2.00 M NaNO 3 2) Dilute to 500 ml The following questions refer to the following unbalanced reaction of ethanol (C 2 H 5 OH ) C 2 H 5 OH + O 2 CO 2 + H 2 O a. State what type of reaction is occurring. b. Calculate the grams of oxygen needed to react with grams of ethanol. c. Calculate the number of CO 2 molecules produced. d. The density of ethanol g/cm 3. Calculate the volume of ethanol needed to provide grams. The following questions refer to this equation: H 2 SO 4 + NaOH H 2 O + Na 2 SO 4 a. Calculate how many moles of NaOH are present in 25.0 ml of M NaOH. b. Calculate how many grams of Na 2 SO 4 are produced if the 25.0 ml of M NaOH reacts. c. Calculate the moles of H 2 SO 4 that would be required. d. Calculate the volume of H 2 SO 4 required if the concentration is M. e. State what type of reaction occurred. 8

9 5. a) 10.0 mol b) 1.67 mol 5. a) 10.0 mol b) 1.67 mol 7. a) 21.9 g b) 29.3 g c) 6.60 g 11 a) 83.6 g b) 5.74 mol c) 279 g d) g e) 175 g g Fe, 4.05 X Fe 2 O g Cu g Cl 2 23.a) 1.60 mol b) 1.50 mol c) 2.81 mol d) 1.90 mol g g CO 2, 10.4 g HCl 23.a) 1.60 mol b) 1.50 mol c) 2.81 mol d) 1.90 mol mol Al remaining g CO g mol g AgCl, 3.5 g CaCl g CO 2, 10.4 g HCl g, 70.7% % g % g H g % g g M a) M h) 49.0 g b) 1.40 M i) 2.00 ml c) 12.4 L d) 41.4 g e) M f) mol g) 307 ml g L M L ml 9

10 Sodium bicarbonate (NaHCO 3 ) was decomposed to compare the actual mass of sodium carbonate (Na 2 CO 3 ) to the theoretical mass. About two grams of NaHCO 3 was placed in a petri dish. The dish was heated on a hotplate, allowed to cool, and then massed. The theoretical mass of Na 2 CO 3 was calculated from the chemical equation and compared to the actual mass. This experiment was accurate, with a percent error of 5.3%. The experiment was not precise because it produced a range of 0.80 grams in the actual mass of Na 2 CO C D C D B B C C A D B D B D D 4. Na 2 S(s) 2Na + (aq) + S 2- (aq) Lab Notes Goggles Use aluminum pans instead of petri dishes 4 trials total Mark your dishes Wash dishes out at end and leave all materials at station BE CLEANER ABOUT THE BALANCE!!!!! Ignore back of sheet, use AP lab report format All work must be unique Reaction Stoichiometry g g g g g g g g g g g g Stoichiometry: You write the reaction g g g g g g g moles g g Molarity (WS) M ml g M ml ml M 14. Same g ml M ml M ml 10

11 Writing Directions (WS) 1. Mass 9.88 g, dissolve in small volume, dilute to 1 L 2. Mass 1.85 g, dissolve in small volume, dilute to 750 ml 3. Mass g, dissolve in small volume, dilute to 17 ml 4. Mass 4.69 g, dissolve in small volume, dilute to 600 ml 5. Mass 4.80 g, dissolve in small volume, dilute to 500 ml 6. Mass 5.20 g, dissolve in small volume, dilute to 1 L 7. Mass 32.0 g, dissolve in small volume, dilute to 850 ml 8. Mass 14.4 g, dissolve in small volume, dilute to 500 ml 9. Mass 6.11 g, dissolve in small volume, dilute to 250 ml 10. Mass 2.20 g, dissolve in small volume, dilute to 100 ml 100 g 2.69 mol 1.79 mol 100 g 2.69 mol 1.79 mol 48.3 g 11

12 g 12

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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)