Thermodynamics- Chapter 19 Schedule and Notes

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Thermodynamics- Chapter 19 Schedule and Notes"

Transcription

1 Thermodynamics- Chapter 19 Schedule and Notes Date Topics Video cast DUE Assignment during class time One Review of thermodynamics 1_thermo_review AND Review of thermo Wksheet 2.1ch19_intro Optional: 1sc_thermo Two ; state function demo 2.2ch19_qualitative_two AND 1, 2, 7, 11, 21, 29a, 30a, ch19_qualitative_three Optional: 3_sc_thermo Three video_thermo AND 5video_thermo 39, 40, 47, 51, 52 Optional: 4sc_thermo Four sc_thermo 53, 55, 57, 60, 64 Five video_thermo 71, 74, 75, 79 Six Enthalpy, Entropy and Gibbs Lab Seven Review Practice Tests Eight Nine Practice Test Review and in-class quiz Test

2 Sample Problems and Notes for Review of Thermodynamics VideoCast 2008 Energy and physical or chemical processes. Measured in 1 st law of Thermodynamics: Endo vs Exo: Heat at constant pressure is called: Diagrams: Ways to find Enthalpy of a Process: 1) Using info from an equation 2) Calorimetry 3) Hess Law 4) Enthalpy of Formation 5) Bond Enthalpies 1) Information from an Equation 2H 2 O 2 (l) 2H 2 O(l) + O 2 (g) H= -196 kj What is the heat (q) [or H, since it is at constant pressure)] when 5.0g of H2O2 decomposes? Think of the reverse of this question too.

3 2) Calorimetry At constant pressure, two equations: How much heat is needed to warm 250g of H 2 O from 22C to 98C. c H2O = J/gK What is the molar heat capacity (Cp) of H 2 O? More calorimetry Examples: When a student mixes 50mL of 1.0M HCl and 50mL of 1.0M NaOH in a coffee-cup calorimeter, the temperature of the resultant solution increases from 21.0 C to 27.5 C. Calculate the enthalpy change for the reaction, assuming that the calorimeter loses only a negligible quantity of heat, that the total volume of the solution is 100.0mL, that its density is 1.0g/mL, and that its specific heat is 4.184J/g C.

4 Constant Volume Calorimetry (Bomb Calorimetry): Methylhydrazine (CH 6 N 2 ) is commonly used as a liquid rocket fuel. The combustion of methylhydrazine with oxygen produces nitrogen, carbon dioxide and water. 2CH 6 N 2 + 5O 2 2N 2 + 2CO 2 + 6H 2 O When 4.00g of methylhydrazine is combusted in a bomb calorimeter, the temperature of the calorimeter increases from C to C. In a separate experiment the heat capacity of the calorimeter is measured to be kj/ C. What is the heat of reaction for the combustion of a mole of CH 6 N 2? 3) Hess Law Calculate H for the reaction: 2C (s) + H 2(g) C 2 H 2(g) Given the following reactions and their respective enthalpy changes: C 2 H 2(g) + 5/2O 2(g) 2CO 2 + H 2 O H = kJ C (s) + O 2(g) CO 2(g) H = kJ H 2(g) + 1/2O 2(g) H 2 O H = kJ 4) Standard Enthalpies of Formation, p. 191ff Use values from appendix C, pg 1123, to determine the enthalpy of reaction for the combustion of pentane gas to form carbon dioxide gas and liquid water. (p193)

5 5) Using Bond Enthalpies, p.332 Bond enthalpy is the enthalpy change, H, for the breaking of a particular bond in one mole of a gaseous substance. Use bond enthalpies from p.330 in your text to estimate the enthalpy of reaction for the combustion of gaseous ethane, producing carbon dioxide gas and water vapor. p. 332.

6 Thermochemistry Review Worksheet 1) The SI unit for energy is the Joule. Show how the units of meter, second and kilogram can be used to define Joule. 2) What is the first law of thermodynamics? 3) Thermodynamic quantities are always identified by a number and a sign (+ or -). What does each tell us about a system? 4) How much heat is released when 4.50g of methane gas is burned in a constant pressure system? (the H for the combustion of methane is 890kJ/mol) 5) Large beds of rocks are used in some solar-heated homes to store heat. a) calculate the quantity of heat absorbed by 50.0kg of rocks if their temperature increases by 12.0 C. (Assume the specific heat of the rocks is 0.82 J/gK) b) What temperature change would these rocks undergo if they absorbed 450kJ of heat?

7 6) When solutions containing silver ions and chloride ions are mixed, silver chloride precipitates. a) write the thermochemical equation for this process assuming H = 65.5kJ/mol b) the energy for a reaction such as this is sometimes called the energy of precipitation or heat of precipitation or H of formation. Calculate the H of formation of mol of AgCl. c) Calculate the H when mmol (yes, milli-moles!) of AgCl dissolves in water.

8 7) A coffee-cup calorimeter of the type shown in figure 6.5 on page 185 of your text contains g of water at 25.1 C. A 121.0g block of Cu metal is heated to C by putting it in a beaker of boiling water. The specific heat of Cu(s) is J/gK. The Cu is added to the calorimeter and after a time the contents of the cup reach a constant temperature of 30.1 C. a) Determine the amount of heat, in Joules, lost by the copper block. b) Determine the amount of heat gained by the water (the specific heat of water is J/gK). c) The difference between your answers for (a) and (b) is due to the heat loss though the styrofoam cups and the heat necessary to raise the temperature of the inner wall of the apparatus. The heat capacity of the calorimeter is the amount of heat necessary to raise the temperature of the apparatus (the cups and the cover) by 1K. Calculate the heat capacity of the calorimeter in J/K. d) If only one Styrofoam cup were used in the apparatus, rather than two, would you expect the heat capacity of the calorimeter to increase, decrease or stay the same? Explain. e) What would be the final temperature of the system if all the heat lost by the Cu block were absorbed by the water in the calorimeter?

9 8) Calculate H for the reaction NO (g) + O (g) NO 2(g) Given the following: NO (g) + O 3(g) NO 2(g) + O 2(g) H=-198.9kJ O 2(g) 2O (g) H=495.0kJ O 3(g) 3/2O 2(g) H=-142.3kJ 9) What is the standard enthalpy of formation? What does the little mean in the term H? How do you use standard enthalpies of formation to find H rxn? 10) Use values from Appendix 4 (page A22) in your text to calculate a) the enthalpy change for the combustion of 1 mol of ethanol b) the combustion of 4.5g of ethanol. c) Now compare the energy in (b) with the combustion of 4.5g of methane gas (#3 above) which is greater? Why? 11) Use bond enthalpies from p.330 in your text to estimate the bond enthalpy of a nitrogen-nitrogen triple bond, when it is produced in the following reaction: N 2 H 4 (g) N 2 (g) + 2H 2 (g) H = -86kJ

10 Videos 2.1 and 2.2 and 3.1 qualitative aspects of thermodynamics video notes on this page. Write neat and large and use lots of white space on this and other pages provided by you.

11 Sample Problems, Chapter 19 These note pages start with video 3.2video_thermo Predict whether the following processes are spontaneous as described, spontaneous in the reverse direction, or in equilibrium: a) when a piece of metal heated to 150 C is added to water at 40 C, the water gets hotter. b) Water at room temperature decomposes into H 2(g) and O 2(g). c) Benzene vapor, C 6 H 6(g), at a pressure of 1atm condenses to liquid benzene at the normal boiling point of benzene, 80.1 C. If a process is nonspontaneous, does that mean that it cannot occur under any circumstances? The element mercury, Hg, is a silvery liquid at room temperature. The normal freezing point of mercury is 38.9 C, and its molar enthalpy of fusion is H fusion = 2.29kJ/mol. What is the entropy change of the system when 50.0g of Hg (l) freezes at the normal freezing point? Extra The normal boiling point of ethanol is 78.3 C and its molar enthalpy of vaporization is kj/mol. What is the change in entropy in the system when 68.3g of C 2 H 5 OH (g) at 1atm condenses to liquid at the normal boiling point? The second law of thermodynamics says that entropy..

12 19.3 Microstates not super important, but helps in understanding S = k lnw What is W? Predict whether S is positive or negative for each of the following processes, assuming each occurs at a constant temperature: a) H 2 O (l) H 2 O (g) b) Ag + (aq) + Cl - (aq) AgCl (s) c) 4Fe (s) + 3O 2(g) 2Fe 2 O 3(s) d) N 2(g) + O 2(g) 2NO (g) Choose the sample of matter that has greater entropy in each pair and explain your choice: a) 1 mol of NaCl (s) or 1 mol of HCl (g) at 25 C b) 2 mol of HCl (g) or 1 mol of HCl (g) at 25 C c) 1 mol of HCl (g) or 1 mol of Ar (g) at 298K If you are told that the entropy of a certain system is zero, what do you know about the system? 19.4 Calculate the S for the synthesis of ammonia from N 2(g) and H 2(g) at 298K: N 2(g) + 3H 2(g) 2NH 3(g)

13 You try: Using the standard entropies in Appendix C, calculate the standard entropy change, S, for the following reaction at 298K: Al 2 O 3(s) + 3H 2(g) 2Al (s) + 3H 2 O (g) 19.5 What are the criteria for spontaneity in terms of: a) entropy b) free energy Calculate the standard free-energy change for the following reaction at 298K: P 4(g) + 6Cl 2(g) 4PCl 3(g)

14 What is G for the reverse of this reaction? C 3 H 8(g) + 5O 2(g) 3CO 2(g) + 4H 2 O (l) H = kj Without using data from appendix C, predict whether the Gibbs Free Energy for this reaction is more negative or less negative than H. Use data from appendix C to calculate the standard free energy change for the reaction at 298K. Is your prediction correct? 19.6 The Haber Process: N 2(g) + 3H 2(g) 2NH 3(g) Assume that H and S for this reaction do not change with temperature. a) predict the direction in which G for this reaction changes with increasing temperature. b) Calculate the values of G for the reaction at 25 C and 500 C

15 Using standard enthalpies of formation and standard entropies in appendix C, calculate H and S at 298K for the following reaction: 2SO 2(g) + O 2(g) 2SO 3(g) Using the values obtained, estimate G at 400K The Haber Process: N 2(g) + 3H 2(g) 2NH 3(g) Calculate G at 298K for a reaction mixture that consists of 1.0atm N 2, 3.0 atm H 2, and 0.50 atm NH 3.

16 Use standard free energies of formation to calculate the equilibrium constant, K, at 25 C for the reaction involved in the Haber process: The Haber Process: N 2(g) + 3H 2(g) 2NH 3(g) The standard free-energy change for this reaction was calculated in an earlier practice problem it was 33.3kJ/mol = J/mol. Use data from appendix C to calculate the standard free-energy change, G, and the equilibrium constant, K, at 298K for the reaction: H 2(g) + Br 2(l) 2HBr (g)

17 1991 D (Required) BCl 3 (g) + NH 3 (g) Cl 3 BNH 3 (s) The reaction represented above is a reversible reaction. (a) Predict the sign of the entropy change, S, as the reaction proceeds to the right. Explain your prediction. (b) If the reaction spontaneously proceeds to the right, predict the sign of the enthalpy change, H. Explain your prediction. (c) The direction in which the reaction spontaneously proceeds changes as the temperature is increased above a specific temperature. Explain. (d) What is the value of the equilibrium constant at the temperature referred to in (c); that is, the specific temperature at which the direction of the spontaneous reaction changes? Explain. Answer: (a) Because a mixture of 2 gases produces a single pure solid, there is an extremely large decrease in entropy, S < 0, i.e. the sign of S is negative. (b) In order for a spontaneous change to occur in the right direction, the enthalpy change must overcome the entropy change which favors the reactants (left), since nature favors a lower enthalpy, then the reaction must be exothermic to the right, H < 0. (c) G = H T S, the reaction will change direction when the sign of G changes, since H < 0 and S < 0, then at low temperatures the sign of G is negative and spontaneous to the right. At some higher T, H = T S and G = 0, thereafter, any higher temperature will see G as positive and spontaneous in the left direction. (d) At equilibrium, K = e G/RT, where G = 0, K = e o = D 2 C 4 H 10 (g) + 13 O 2 (g) 8 CO 2 (g) + 10 H 2 O(l) The reaction represented above is spontaneous at 25 C. Assume that all reactants and products are in their standard state. (a) Predict the sign of S for the reaction and justify your prediction. (b) What is the sign of G for the reaction? How would the sign and magnitude of G be affected by an increase in temperature to 50 C? Explain your answer. (c) What must be the sign of H for the reaction at 25 C? How does the total bond energy of the reactants compare to that of the products? (d) When the reactants are place together in a container, no change is observed even though the reaction is known to be spontaneous. Explain this observation. Answer: (a) S<0. The number of moles of gaseous products is less than the number of moles of gaseous reactants. OR A liquid is formed from gaseous reactants. (b) G<0. G becomes less negative as the temperature is increased since S < 0 and G = H T S. The term T S adds a positive number to H. (c) H<0. The bond energy of the reactants is less than the bond energy of the products. (d) The reaction has a high activation energy; OR is kinetically slow; OR a specific mention of the need for a catalyst or spark.

18 1994 D 2 H 2 S(g) + SO 2 (g) 3 S(s) + 2 H 2 O(g) At 298 K, the standard enthalpy change, H for the reaction represented above is 145 kilojoules. (a) Predict the sign of the standard entropy change, S, for the reaction. Explain the basis for your prediction. (b) At 298 K, the forward reaction (i.e., toward the right) is spontaneous. What change, if any, would occur in the value of G for this reaction as the temperature is increased? Explain your reasoning using thermodynamic principles. (c) What change, if any, would occur in the value of the equilibrium constant, K eq, for the situation described in (b)? Explain your reasoning. (d) The absolute temperature at which the forward reaction becomes nonspontaneous can be predicted. Write the equation that is used to make the prediction. Why does this equation predict only an approximate value for the temperature? Answer: (a) S is negative ( ). A high entropy mixture of two kinds of gases forms into a low entropy solid and a pure gas; 3 molecules of gas makes 2 molecules of gas, fewer gas molecules is at a lower entropy. (b) G < 0 if spontaneous. G = H T S Since S is neg. ( ), as T gets larger, T S will become larger than +145 kj and the sign of G becomes pos. (+) and the reaction is non spontanseous. (c) When T S < +145 kj, K eq > 1, when T S = +145 kj, K eq = 1, when T S > +145 kj, K eq < 1, but > 0 (d) G = 0 at this point, the equation is T = H ; this assumes that H and/or S do not change with temperature; not a perfect assumption leading to errors in the S calculation B C 2 H 2 (g) + 2 H 2 (g) C 2 H 6 (g) Information about the substances involved in the reaction represented above is summarized in the following tables. (a) Substance S (J/mol K) H f (kj/mol) C 2 H 2 (g) H 2 (g) C 2 H 6 (g) Bond Bond Energy (kj/mol) C C 347 C=C 611 C H 414 H H 436 If the value of the standard entropy change, S, for the reaction is joules per mole Kelvin, calculate the standard molar entropy, S, of C 2 H 6 gas. (b) Calculate the value of the standard free-energy change, G, for the reaction. What does the sign of G indicate about the reaction above? (c) Calculate the value of the equilibrium constant, K, for the reaction at 298 K. (d) Calculate the value of the C C bond energy in C 2 H 2 in kilojoules per mole.

19 Answer: (a) J/K = S (C2 H 6 ) [2(130.7) ] J/K (b) S (C2 H 6 ) = J/K H = H ƒ (products) H ƒ (reactants) = 84.7 kj [ (0)] kj = kj G = H T S = kj (298K)( kj/k) = kj A G < 0 (a negative G ) indicates a spontaneous forward reaction. (c) K eq = e G/RT = e ( /(8.314)(298)) (d) = H = bond energy of products bond energy of reactants kj = [(2)(436) + E c c + (2)(414)] [347 + (6)(414)] kj E c c = 820 kj 1997 D For the gaseous equilibrium represented below, it is observed that greater amounts of PCl 3 and Cl 2 are produced as the temperature is increased. PCl 5 (g) PCl 3 (g) + Cl 2 (g) (a) (b) (c) (d) What is the sign of S for the reaction? Explain. What change, if any, will occur in G for the reaction as the temperature is increased? Explain your reasoning in terms of thermodynamic principles. If He gas is added to the original reaction mixture at constant volume and temperature, what will happen to the partial pressure of Cl 2? Explain. If the volume of the reaction mixture is decreased at constant temperature to half the original volume, what will happen to the number of moles of Cl 2 in the reaction vessel? Explain. Answer: (a) The sign of S is (+). There is an increase in the number of gas molecules as well as a change from a pure gas to a mixture of gases. (b) G = H T S. Both S and H are (+). As temperature increases, at some point the sign of G will change from (+) to ( ), when the system will become spontaneous. (c) There will be no change in the partial pressure of the chlorine. Without a volume or temperature change, the pressure is independent of the other gases that are present. (d) The number of moles of Cl 2 will decrease. The decrease in volume will result in an increase in pressure and, according to LeChatelier s Principle, the equilibrium system will shift to the left (the side with fewer gas molecules) to reduce this increase in pressure. This will cause a decrease in the number of moles of products and an increase in the number of moles of reactant.

20 1. To measure enthalpy. 2. To calculate entropy. 3. To calculate Gibbs free energy. THERMODYNAMICS ENTHALPY, ENTROPY and GIBBS FREE ENERGY OBJECTIVES The Gibbs free energy is (delta G) is a measure of the spontaneity of a process and of the useful energy available from it. Negative delta G indicates a spontaneous process. Positive delta G indicates a nonspontaneous process or a process spontaneous in opposite direction Delta G is calculated from the equation: Delta G= delta H T delta S In today s experiments we will measure experimentally change in enthalpy, delta H, and obtain change in entropy, delta S, from the table data. After completing the calculations answer the following questions separately for each experiment: 1. Is the dissolving exothermic or endothermic? 2. Does the entropy decreases or increases during dissolving? 3. Is the Gibbs free energy positive or negative? Is the process of dissolving spontaneous?

21 Teacher Notes -- EXAMPLES OF CALCULATIONS: 1. Measurement and calculations of delta H g of magnesium sulfate was dissolved in 300. ml of water at 23.3 degree C in a coffee-cup calorimeter. After dissolving, the temperature increased to 36.6 degree C. Write the thermochemical equation for the reaction, that is, calculate the enthalpy for the reaction: MgSO4(s) --> Mg 2+ (aq) + SO4 2 (aq) Assume that the calorimeter loses only a negligible quantity of heat, density of the solutions is 1.00 g/ml, and the specific heat of the solutions is J/g K. Since adding the crystals doesn t change the volume noticeably, assume the mass of solution to be 300. g. Step 1. Calculate the heat produced in the reaction: heat = sp. heat of solution x mass of solution x delta T or qsoln = csoln x masssoln x delta Tsoln qsoln =4.184 J/g K x 300. g x 13.3 K = J = 16.7 kj Step 2. Calculate how many moles are 22.0 g of magnesium sulfate g x 1 mol/120.4 g = mol MgSO4 Step 3. Calculate the heat evolved per one mole of magnesium sulfate. This is the sought delta H value. Enthalpy will be negative, ( ), since it is an exothermic reaction (the temperature went up). 1 mol x 16.7 kj/0.183 mol = 91.3 kj Step 4. Rewrite the equation with state symbols and with the delta H value. Enthalpy is expressed per number of moles in the equation, in this case, per one mole. MgSO4(s) >Mg 2+ (aq) + SO4 2 (aq) delta H = kj 2. Delta S from standard tabulated data. MgSO4(s) 91.6 S (J/K mol) Mg 2+ (aq) SO4 2 (aq) 20.1 Delta S = S products - S reactants Delta S = [Mg 2+ (aq) + SO4 2 (aq)] - MgSO4(s) Delta S = [ J/K mol J/K mol] J/K mol = J/K mol This value indicates that entropy decreases during the dissolving. This is a rare case. It is related to formation of regular structures of water surrounding the ions. 3. Calculation of the Gibbs free energy. In all calculations we will use the standard temperature 298 K which is close to a room temperature. Enthalpy and entropy doesn t change significantly in our range of temperatures. Remember that H is usually expresses in kj and S in J. Perform appropriate conversions before calculating G. Delta G= delta H T delta S Delta G = J/mol - [298 K x ( J/K mol)] = J = kj/mol Negative value of delta G indicates that dissolving magnesium sulfate is spontaneous.

Standard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K

Standard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K 1 Thermodynamics There always seems to be at least one free response question that involves thermodynamics. These types of question also show up in the multiple choice questions. G, S, and H. Know what

More information

Chapter 16 Review Packet

Chapter 16 Review Packet Chapter 16 Review Packet AP Chemistry Chapter 16 Practice Multiple Choice Portion 1. For which process is ΔS negative? Note: ΔS = S final S initial therefore, if ΔS is positive, S final > S initial if

More information

Name: Thermochemistry. Practice Test B. General Chemistry Honors Chemistry

Name: Thermochemistry. Practice Test B. General Chemistry Honors Chemistry Name: Thermochemistry B Practice Test B General Chemistry Honors Chemistry 1 Objective 1: Use the relationship between mass, specific heat, and temperature change to calculate the heat flow during a chemical

More information

Name: Thermochemistry. Practice Test A. General Chemistry Honors Chemistry

Name: Thermochemistry. Practice Test A. General Chemistry Honors Chemistry Name: Thermochemistry Practice Test A General Chemistry Honors Chemistry 1 Objective 1: Use the relationship between mass, specific heat, and temperature change to calculate the heat flow during a chemical

More information

CHEM 1411, chapter 6. Thermochemistry Exercises

CHEM 1411, chapter 6. Thermochemistry Exercises CHEM 1411, chapter 6. Thermochemistry Exercises 1. The heat capacity of 20.0 g of water is 83.7 J/ C. A) True B) False 2. Find the heat absorbed from the surroundings when 15 g of O 2 reacts according

More information

Chapter 5 Thermochemistry

Chapter 5 Thermochemistry Chapter 5 Thermochemistry I. Nature of Energy Energy units SI unit is joule, J From E = 1/2 mv 2, 1J = 1kg. m 2 /s 2 Traditionally, we use the calorie as a unit of energy. 1 cal = 4.184J (exactly) The

More information

CHEMISTRY Practice exam #4 answer key October 16, 2007

CHEMISTRY Practice exam #4 answer key October 16, 2007 CHEMISTRY 123-01 Practice exam #4 answer key October 16, 2007 1. An endothermic reaction causes the surroundings to a. warm up. b. become acidic. c. condense. 2. Which of the following is an example of

More information

Calorimeter: A device in which the heat associated with a specific process is measured.

Calorimeter: A device in which the heat associated with a specific process is measured. 1 CALORIMETRY p. 661-667 (simple), 673-675 (bomb) Calorimeter: A device in which the heat associated with a specific process is measured. There are two basic types of calorimeters: 1. Constant-pressure

More information

Practice Test Questions:

Practice Test Questions: Practice Test Questions: There are a lot of questions. Please feel free to do a problem, skip around and make sure you are doing all types of problems heat exchange, Hess Law problems, specific heat problems,

More information

Bomb Calorimetry. Example 4. Energy and Enthalpy

Bomb Calorimetry. Example 4. Energy and Enthalpy Bomb Calorimetry constant volume often used for combustion reactions heat released by reaction is absorbed by calorimeter contents need heat capacity of calorimeter q cal = q rxn = q bomb + q water Example

More information

Chapter 5. Thermochemistry

Chapter 5. Thermochemistry Chapter 5. Thermochemistry THERMODYNAMICS - study of energy and its transformations Thermochemistry - study of energy changes associated with chemical reactions Energy - capacity to do work or to transfer

More information

Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16

Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16 Name AP CHEM / / Collected AP Exam Essay Answers for Chapter 16 1980 - #7 (a) State the physical significance of entropy. Entropy (S) is a measure of randomness or disorder in a system. (b) From each of

More information

Thermodynamics. Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life

Thermodynamics. Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life Thermodynamics Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life Thermodynamics is the study of the transformation of energy into heat and for doing

More information

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510)

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) 17 THERMOCHEMISTRY SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) This section explains the relationship between energy and heat, and distinguishes between heat capacity and specific heat.

More information

The first law: transformation of energy into heat and work. Chemical reactions can be used to provide heat and for doing work.

The first law: transformation of energy into heat and work. Chemical reactions can be used to provide heat and for doing work. The first law: transformation of energy into heat and work Chemical reactions can be used to provide heat and for doing work. Compare fuel value of different compounds. What drives these reactions to proceed

More information

CHAPTER 17: THERMOCHEMISTRY. Heat vs. Temperature. Heat vs. Temperature. q = mc T. Heat Capacity vs. Specific Heat

CHAPTER 17: THERMOCHEMISTRY. Heat vs. Temperature. Heat vs. Temperature. q = mc T. Heat Capacity vs. Specific Heat CHAPTER 17: THERMOCHEMISTRY Page 504 539 Heat vs. Temperature ATOM Heat energy= Kinetic energy SUBSTANCE Heat energy = TOTAL Kinetic energy of all atoms in a substance Temperature = AVERAGE Kinetic energy

More information

THERMOCHEMISTRY & DEFINITIONS

THERMOCHEMISTRY & DEFINITIONS THERMOCHEMISTRY & DEFINITIONS Thermochemistry is the study of the study of relationships between chemistry and energy. All chemical changes and many physical changes involve exchange of energy with the

More information

Thermochemistry. Thermochemistry 1/25/2010. Reading: Chapter 5 (omit 5.8) As you read ask yourself

Thermochemistry. Thermochemistry 1/25/2010. Reading: Chapter 5 (omit 5.8) As you read ask yourself Thermochemistry Reading: Chapter 5 (omit 5.8) As you read ask yourself What is meant by the terms system and surroundings? How are they related to each other? How does energy get transferred between them?

More information

3. Of energy, work, enthalpy, and heat, how many are state functions? a) 0 b) 1 c) 2 d) 3 e) 4 ANS: c) 2 PAGE: 6.1, 6.2

3. Of energy, work, enthalpy, and heat, how many are state functions? a) 0 b) 1 c) 2 d) 3 e) 4 ANS: c) 2 PAGE: 6.1, 6.2 1. A gas absorbs 0.0 J of heat and then performs 15.2 J of work. The change in internal energy of the gas is a) 24.8 J b) 14.8 J c) 55.2 J d) 15.2 J ANS: d) 15.2 J PAGE: 6.1 2. Calculate the work for the

More information

6.1 Some basic principles

6.1 Some basic principles Ch 6 Thermochemistry: Energy Flow and Chemical Change 6.1 Forms of Energy and Their Interconversion 6.2 Enthalpy: Heats of Reaction and Chemical Change 6.3 Calorimetry: Laboratory Measurement of Heats

More information

H 2 (g) + ½ O 2 (g) H 2 O(l) H o f [NO(g)] = 90.2 kj/mol; H o f [H 2 O(g)] = kj/mol H o f [NH 3 (g)] = kj/mol; H o f [O 2 (g)] =?

H 2 (g) + ½ O 2 (g) H 2 O(l) H o f [NO(g)] = 90.2 kj/mol; H o f [H 2 O(g)] = kj/mol H o f [NH 3 (g)] = kj/mol; H o f [O 2 (g)] =? Chapter 16 Thermodynamics GCC CHM152 Thermodynamics You are responsible for Thermo concepts from CHM 151. You may want to review Chapter 8, specifically sections 2, 5, 6, 7, 9, and 10 (except work ). Thermodynamics:

More information

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry The Relationships Between Internal Energy, Heat, Enthalpy, and Calorimetry Recap of Last Class Last class, we began our discussion about energy changes that accompany chemical reactions Chapter 5 discusses:

More information

CHAPTER 6 THERMOCHEMISTRY

CHAPTER 6 THERMOCHEMISTRY Chapter 6 Thermochemistry Page 1 CHAPTER 6 THERMOCHEMISTRY 6-1. The standard state of an element or compound is determined at a pressure of and a temperature of. (a) 760 atm, 0 o C (b) 1 mmhg, 273 o C

More information

3A Energy. What is chemical energy?

3A Energy. What is chemical energy? 3A Energy What is chemical energy? Chemical energy is a form of potential energy which is stored in chemical bonds. Chemical bonds are the attractive forces that bind atoms together. As a reaction takes

More information

Chapter Six. Energy Relationships in Chemical Reactions

Chapter Six. Energy Relationships in Chemical Reactions Chapter Six Energy Relationships in Chemical Reactions 1 Energy (U): Capacity to Do Work Radiant energy Energy from the sun Nuclear energy Energy stored in the nucleus of an atom Thermal energy Energy

More information

Thermodynamics. S (reactants) S S (products) AP Chemistry. Period Date / / R e v i e w. 1. Consider the first ionization of sulfurous acid:

Thermodynamics. S (reactants) S S (products) AP Chemistry. Period Date / / R e v i e w. 1. Consider the first ionization of sulfurous acid: AP Chemistry Thermodynamics 1. Consider the first ionization of sulfurous acid: H 2SO 3(aq) H + (aq) + HSO 3 - (aq) Certain related thermodynamic data are provided below: H 2SO 3(aq) H + (aq) HSO 3 - (aq)

More information

Unit 19 Practice. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.

Unit 19 Practice. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question. Name: Class: Date: Unit 19 Practice Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The first law of thermodynamics can be given as. A) E = q + w B) =

More information

Energy Changes in Chemical Reactions. System loses heat (negative); gains heat (positive) Describe the difference between the two.

Energy Changes in Chemical Reactions. System loses heat (negative); gains heat (positive) Describe the difference between the two. Energy Changes in Chemical Reactions Most reactions give off or absorb energy Energy is the capacity to do work or supply heat. Heat: transfer of thermal (kinetic) energy between two systems at different

More information

Chemistry Guide

Chemistry Guide 551534 - Chemistry Guide 1- Contents Question Item Objective Type Skill 1 0102 M03.02.04 Multiple-choice answer Mastery of Problem Solving 2 0099 M03.03.02 Multiple-choice answer Mastery of Concepts 3

More information

ΔU = q + w = q - P ΔV. 3. What are extensive and intensive properties and some examples of each?

ΔU = q + w = q - P ΔV. 3. What are extensive and intensive properties and some examples of each? Worksheet 2 1. Energy and Enthalpy. A system can exchange energy with its surroundings either by transferring heat or by doing work. Using q to represent transferred heat and w = - P ΔV, the total energy

More information

AP* Chemistry THERMOCHEMISTRY

AP* Chemistry THERMOCHEMISTRY AP* Chemistry THERMOCHEMISTRY Terms for you to learn that will make this unit understandable: Energy (E) the ability to do work or produce heat ; the sum of all potential and kinetic energy in a system

More information

Chapter 20. Thermodynamics p. 811 842. Spontaneity. What have we learned about spontaneity during this course?

Chapter 20. Thermodynamics p. 811 842. Spontaneity. What have we learned about spontaneity during this course? Chapter 20 p. 811 842 Spontaneous process: Ex. Nonspontaneous process: Ex. Spontaneity What have we learned about spontaneity during this course? 1) Q vs. K? 2) So.. Spontaneous process occurs when a system

More information

Chemistry 102 Chapter 17 THERMODYNAMICS

Chemistry 102 Chapter 17 THERMODYNAMICS THERMODYNAMICS Thermodynamics is concerned with the energy changes that accompany chemical and physical processes. Two conditions must be fulfilled in order to observe a chemical or physical change: The

More information

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well.

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well. Chem 130 Name Exam 3, Ch 7, 19, and a little 14 November 11, 2011 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with

More information

Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law

Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law GOAL AND OVERVIEW A simple calorimeter will be made and calibrated. It will be used to determine the heat of fusion of ice, the specific

More information

HEAT, TEMPERATURE, & THERMAL ENERGY

HEAT, TEMPERATURE, & THERMAL ENERGY HEAT, TEMPERATURE, & THERMAL ENERGY Energy A property of matter describing the ability to do. Work - is done when an object is moved through a distance by a force acting on the object. Kinetic Energy Associated

More information

CHEMISTRY 110 Assignment #3 - answers 2011.

CHEMISTRY 110 Assignment #3 - answers 2011. 1. Titanium metal is used as a structural material in many high tech applications such as in jet engines. What is the specific heat of titanium in J/() if it takes 89.7 J to raise the temperature of a

More information

Chapter 5: thermochemstry. Internal Energy: E

Chapter 5: thermochemstry. Internal Energy: E Chapter 5: thermochemstry tonight s goals Energy and Enthalpy Review Enthalpies of Reaction Calorimetry Hess Law Enthalpies of Formation Internal Energy: E E = The sum of all kinetic and potential energies

More information

EXPERIMENT 9. Thermochemistry: Hess Law and the Heat of Formation of MgO

EXPERIMENT 9. Thermochemistry: Hess Law and the Heat of Formation of MgO Outcomes EXPERIMENT 9 Thermochemistry: Hess Law and the Heat of Formation of MgO After completing this experiment, the student should be able to: 1. Differentiate between exothermic and endothermic reactions.

More information

87 16 70 20 58 24 44 32 35 40 29 48 (a) graph Y versus X (b) graph Y versus 1/X

87 16 70 20 58 24 44 32 35 40 29 48 (a) graph Y versus X (b) graph Y versus 1/X HOMEWORK 5A Barometer; Boyle s Law 1. The pressure of the first two gases below is determined with a manometer that is filled with mercury (density = 13.6 g/ml). The pressure of the last two gases below

More information

Enthalpy changes and calorimetry. Enthalpy changes in reactions Calorimetry and heat measurement Hess s Law Heats of formation

Enthalpy changes and calorimetry. Enthalpy changes in reactions Calorimetry and heat measurement Hess s Law Heats of formation Enthalpy changes and calorimetry Enthalpy changes in reactions Calorimetry and heat measurement Hess s Law Heats of formation Learning objectives Describe the standard state for thermodynamic functions

More information

Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen)

Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen) Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen) Energy is defined as the capacity to do work, or transfer heat. Work (w) - force (F) applied through a distance. Force - any

More information

Thermochemical equations allow stoichiometric calculations.

Thermochemical equations allow stoichiometric calculations. CHEM 1105 THERMOCHEMISTRY 1. Change in Enthalpy ( H) Heat is evolved or absorbed in all chemical reactions. Exothermic reaction: heat evolved - heat flows from reaction mixture to surroundings; products

More information

Thermodynamics Review

Thermodynamics Review Thermodynamics Review 1. According to Reference Table I, the dissolving of NH 4Cl(s) in water is 1) exothermic and the heat of reaction is negative 2) exothermic and the heat of reaction is positive 3)

More information

SUGGESTION ANSWER SCHEME CHAPTER 8: THERMOCHEMISTRY. 1 (a) Use the data in the table below to answer the following questions:

SUGGESTION ANSWER SCHEME CHAPTER 8: THERMOCHEMISTRY. 1 (a) Use the data in the table below to answer the following questions: SUGGESTION ANSWER SCHEME CHAPTER 8: THERMOCHEMISTRY ANSWER SCHEME UPS 2004/2005 SK027 1 (a) Use the data in the table below to answer the following questions: Enthalpy change ΔH (kj/mol) Atomization energy

More information

Calorimetry and Enthalpy. Chapter 5.2

Calorimetry and Enthalpy. Chapter 5.2 Calorimetry and Enthalpy Chapter 5.2 Heat Capacity Specific heat capacity (c) is the quantity of thermal energy required to raise the temperature of 1g of a substance by 1⁰C The units for specific heat

More information

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work.

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work. ENERGY Thermochemistry Energy is the capacity to do work. Chapter 6 Kinetic Energy thermal, mechanical, electrical, sound Potential Energy chemical, gravitational, electrostatic Heat Heat, or thermal energy,

More information

Thermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual

Thermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual Thermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual 1. Predict the sign of entropy change in the following processes a) The process of carbonating water to make a soda

More information

4. Using the data from Handout 5, what is the standard enthalpy of formation of BaO (s)? What does this mean?

4. Using the data from Handout 5, what is the standard enthalpy of formation of BaO (s)? What does this mean? HOMEWORK 3A 1. In each of the following pairs, tell which has the higher entropy. (a) One mole of liquid water or one mole of water vapor (b) One mole of dry ice or one mole of carbon dioxide at 1 atm

More information

Spontaneity of a Chemical Reaction

Spontaneity of a Chemical Reaction Spontaneity of a Chemical Reaction We have learned that entropy is used to quantify the extent of disorder resulting from the dispersal of matter in a system. Also; entropy, like enthalpy and internal

More information

Chemistry Thermochemistry Lesson 10 Lesson Plan David V. Fansler

Chemistry Thermochemistry Lesson 10 Lesson Plan David V. Fansler Chemistry Thermochemistry Lesson 10 Lesson Plan David V. Fansler The Flow of Energy-Heat Objectives: Explain the relationship between energy and heat; Distinguish between heat capacity and specific heat.

More information

Thermodynamics. Thermodynamics 1

Thermodynamics. Thermodynamics 1 Thermodynamics 1 Thermodynamics Some Important Topics First Law of Thermodynamics Internal Energy U ( or E) Enthalpy H Second Law of Thermodynamics Entropy S Third law of Thermodynamics Absolute Entropy

More information

ENTHALPY CHANGES FOR A CHEMICAL REACTION scaling a rxn up or down (proportionality) quantity 1 from rxn heat 1 from Δ r H. = 32.

ENTHALPY CHANGES FOR A CHEMICAL REACTION scaling a rxn up or down (proportionality) quantity 1 from rxn heat 1 from Δ r H. = 32. CHEMISTRY 103 Help Sheet #10 Chapter 4 (Part II); Sections 4.6-4.10 Do the topics appropriate for your lecture Prepared by Dr. Tony Jacob http://www.chem.wisc.edu/areas/clc (Resource page) Nuggets: Enthalpy

More information

Calorimetry and Thermochemistry

Calorimetry and Thermochemistry CHEM 121L General Chemistry Laboratory Revision 1.3 Calorimetry and Thermochemistry Learn how to measure Heat flow. Learn about the Specific Heat of substances. Learn about Exothermic and Endothermic chemical

More information

Entropy and Free Energy

Entropy and Free Energy Entropy and Free Energy How to predict if a reaction can occur, given enough time? THERMODYNAMICS 1 Thermodynamics If the state of a chemical system is such that a rearrangement of its atoms and molecules

More information

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics Unit-7 Thermodynamics Introduction: The term Thermo means heat and dynamics means flow or movement.. So thermodynamics is concerned with the flow of heat. The different forms of the energy are interconvertible

More information

Energy and Chemical Reactions. Characterizing Energy:

Energy and Chemical Reactions. Characterizing Energy: Energy and Chemical Reactions Energy: Critical for virtually all aspects of chemistry Defined as: We focus on energy transfer. We observe energy changes in: Heat Transfer: How much energy can a material

More information

Enthalpy, Entropy, and Free Energy Calculations

Enthalpy, Entropy, and Free Energy Calculations Adapted from PLTL The energies of our system will decay, the glory of the sun will be dimmed, and the earth, tideless and inert, will no longer tolerate the race which has for a moment disturbed its solitude.

More information

1. the same as E. correct. 2. less than E. 3. unrelated to E.

1. the same as E. correct. 2. less than E. 3. unrelated to E. Version PREVIEW Exam 3 JONSON (53140) 1 This print-out should have 40 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. LDE Carbon Allotropes

More information

Chapter 18 Homework Answers

Chapter 18 Homework Answers Chapter 18 Homework Answers 18.22. 18.24. 18.26. a. Since G RT lnk, as long as the temperature remains constant, the value of G also remains constant. b. In this case, G G + RT lnq. Since the reaction

More information

As long as the relative ratios are constant the amounts are correct. Using these ratios to determine quantities is called Stoichiometry.

As long as the relative ratios are constant the amounts are correct. Using these ratios to determine quantities is called Stoichiometry. The Meaning of the Balanced Equation Tuesday, October 11, 2011 2:05 PM The Balanced Equation is a measure of the relative amounts of a compounds that participate in or are produced by a reaction. Since

More information

Thermochemistry. r2 d:\files\courses\1110-20\99heat&thermorans.doc. Ron Robertson

Thermochemistry. r2 d:\files\courses\1110-20\99heat&thermorans.doc. Ron Robertson Thermochemistry r2 d:\files\courses\1110-20\99heat&thermorans.doc Ron Robertson I. What is Energy? A. Energy is a property of matter that allows work to be done B. Potential and Kinetic Potential energy

More information

Unit 14 Thermochemistry

Unit 14 Thermochemistry Unit 14 Thermochemistry Name May 5 6 Unit 13 Acids and Bases Test Intro to Thermochemistry Videos (p.2-3) HW: p. 4-5 9 10 11 12 13 Thermochemistry Interpret graphs Heat of reaction & Specific Heat Heat

More information

AP Practice Questions

AP Practice Questions 1) AP Practice Questions The tables above contain information for determining thermodynamic properties of the reaction below. C 2 H 5 Cl(g) + Cl 2 (g) C 2 H 4 Cl 2 (g) + HCl(g) (a) Calculate ΔH for

More information

Chapter 17 Thermodynamics: Directionality of Chemical Reactions

Chapter 17 Thermodynamics: Directionality of Chemical Reactions Reactant- & Product-Favored Processes John W. Moore Conrad L. Stanitski Peter C. Jurs http://academic.cengage.com/chemistry/moore Chapter 17 hermodynamics: Directionality of Chemical Reactions Why are

More information

Example. c. Calculate the amount of heat (in kj) required to heat 1.00 kg (~1 L) of water at 25 C to its boiling point.

Example. c. Calculate the amount of heat (in kj) required to heat 1.00 kg (~1 L) of water at 25 C to its boiling point. Example When consuming an ice-cold drink, one must raise the temperature of the beverage to 37.0 C (normal body temperature). Can one lose weight by drinking ice-cold beverages if the body uses up about

More information

Chemical Equations C5.6b Predict single replacement reactions.

Chemical Equations C5.6b Predict single replacement reactions. Chemistry 2SEM Chemical Equations C5.6b Predict single replacement reactions. Common Assessment Review Predict the following single replacement reactions: a. Zn + Pb(C2H3O2)2 ----> Pb + Zn(C2H3O2)2_ b.

More information

Chem 1A Exam 2 Review Problems

Chem 1A Exam 2 Review Problems Chem 1A Exam 2 Review Problems 1. At 0.967 atm, the height of mercury in a barometer is 0.735 m. If the mercury were replaced with water, what height of water (in meters) would be supported at this pressure?

More information

Thermodynamics: Entropy & Gibbs Free Energy

Thermodynamics: Entropy & Gibbs Free Energy Thermodynamics: Entropy & Gibbs Free Energy PSI Chemistry Name------------------------------------------------------- I. Entropy & the Second Law of Thermodynamics 1) A reaction that is spontaneous. A)

More information

STOICHIOMETRY. - the study of the quantitative aspects of chemical

STOICHIOMETRY. - the study of the quantitative aspects of chemical STOICHIOMETRY - the study of the quantitative aspects of chemical GENERAL PLAN FOR STOICHIOMETRY Mass reactant Mass product Moles reactant Stoichiometric factor Moles product STOICHIOMETRY It rests on

More information

Thermodynamics: First Law, Calorimetry, Enthalpy. Calorimetry. Calorimetry: constant volume. Monday, January 23 CHEM 102H T.

Thermodynamics: First Law, Calorimetry, Enthalpy. Calorimetry. Calorimetry: constant volume. Monday, January 23 CHEM 102H T. Thermodynamics: First Law, Calorimetry, Enthalpy Monday, January 23 CHEM 102H T. Hughbanks Calorimetry Reactions are usually done at either constant V (in a closed container) or constant P (open to the

More information

CHEMISTRY 3310 PROBLEM SHEET #4

CHEMISTRY 3310 PROBLEM SHEET #4 CHEMISTRY 3310 PROBLEM SHEET #4 1. The specific heats of a number of materials are listed below. Calculate the molar heat capacity for each. (a) gold, (b) rust (Fe 2 O 3 ) (c) sodium chloride 2. Calculate

More information

5.2. Determining Enthalpy of Reaction by Experiment. Specific Heat Capacity. 234 MHR Unit 3 Energy Changes and Rates of Reaction

5.2. Determining Enthalpy of Reaction by Experiment. Specific Heat Capacity. 234 MHR Unit 3 Energy Changes and Rates of Reaction In this section, you will 5.2 Section Preview/ Specific Expectations determine the heat that is produced by a reaction using a calorimeter, and use the data obtained to calculate the enthalpy change for

More information

Transfer of heat energy often occurs during chemical reactions. A reaction

Transfer of heat energy often occurs during chemical reactions. A reaction Chemistry 111 Lab: Thermochemistry Page I-3 THERMOCHEMISTRY Heats of Reaction The Enthalpy of Formation of Magnesium Oxide Transfer of heat energy often occurs during chemical reactions. A reaction may

More information

Periodic Table of the Elements

Periodic Table of the Elements Periodic Table of the Elements 1A 8A 1 18 1 2 H 2A 3A 4A 5A 6A 7A He 1.0079 2 13 14 15 16 17 4.0026 3 4 5 6 7 8 9 10 Li Be B C N O F Ne 6.941 9.0122 10.811 12.011 14.0067 15.9994 18.9984 20.1797 11 12

More information

Enthalpy of Reaction and Calorimetry worksheet

Enthalpy of Reaction and Calorimetry worksheet Enthalpy of Reaction and Calorimetry worksheet 1. Calcium carbonate decomposes at high temperature to form carbon dioxide and calcium oxide, calculate the enthalpy of reaction. CaCO 3 CO 2 + CaO 2. Carbon

More information

CHM1045 Practice Test 3 v.1 - Answers Name Fall 2013 & 2011 (Ch. 5, 6, 7, & part 11) Revised April 10, 2014

CHM1045 Practice Test 3 v.1 - Answers Name Fall 2013 & 2011 (Ch. 5, 6, 7, & part 11) Revised April 10, 2014 CHM1045 Practice Test 3 v.1 - Answers Name Fall 013 & 011 (Ch. 5, 6, 7, & part 11) Revised April 10, 014 Given: Speed of light in a vacuum = 3.00 x 10 8 m/s Planck s constant = 6.66 x 10 34 J s E (-.18x10

More information

UNIT 1 THERMOCHEMISTRY

UNIT 1 THERMOCHEMISTRY UNIT 1 THERMOCHEMISTRY THERMOCHEMISTRY LEARNING OUTCOMES Students will be expected to: THERMOCHEMISTRY STSE analyse why scientific and technological activities take place in a variety individual and group

More information

Standard States. Standard Enthalpy of formation

Standard States. Standard Enthalpy of formation Standard States In any thermochemical equation, the states of all reactants and products must be specified; otherwise it becomes difficult for scientists to understand the experimental results of other

More information

Chapter 5 Thermochemistry

Chapter 5 Thermochemistry Chapter 5 Thermochemistry 1. The ΔE of a system that releases 14.4 J of heat and does 4.8 J of work on the surroundings is J. (a). 19.2 J (b). 14.4 J (c). 4.8 J (d). - 19.2 J Explanation: The ΔE can be

More information

Test 2 Equilibrium and Chemical Energy

Test 2 Equilibrium and Chemical Energy Multiple Choice (0 marks - for each question). In a reversible reaction, equilibrium is reached when A molecules of the reactant cease to change into molecules of the product B the concentrations of reactants

More information

Prelab attached (p 8-9) (g)! MgO (s) + heat (1)

Prelab attached (p 8-9) (g)! MgO (s) + heat (1) CHEM 151 ENTHALPY OF FORMATION OF MgO FALL 2008 Fill-in Prelab attached (p 8-9) Stamp Here Name Partner Lecture instructor Date INTRODUCTION Chemical reactions either produce heat as they proceed (exothermic)

More information

Chapter 5 Thermo. Energy & Chemistry. Energy & Chemistry. Units of Energy. Energy & Chemistry. Potential & Kinetic Energy. Some Basic Principles

Chapter 5 Thermo. Energy & Chemistry. Energy & Chemistry. Units of Energy. Energy & Chemistry. Potential & Kinetic Energy. Some Basic Principles 1 Energy & Chemistry effrey Mack California State University, Sacramento Chapter 5 Principles of Chemical Reactivity: Energy and Chemical Reactions Questions that need to be addressed: How do we measure

More information

Chapter 5 Principles of Chemical Reactivity: Energy and Chemical Reactions

Chapter 5 Principles of Chemical Reactivity: Energy and Chemical Reactions PRACTICING SKILLS Energy Chapter 5 Principles of Chemical Reactivity: 1. To move the lever, one uses mechanical energy. The energy resulting is manifest in electrical energy (which produces light); thermal

More information

Chapter 14. CHEMICAL EQUILIBRIUM

Chapter 14. CHEMICAL EQUILIBRIUM Chapter 14. CHEMICAL EQUILIBRIUM 14.1 THE CONCEPT OF EQUILIBRIUM AND THE EQUILIBRIUM CONSTANT Many chemical reactions do not go to completion but instead attain a state of chemical equilibrium. Chemical

More information

(3) AgCl(s) Ag + (aq) + Cl (aq) (4) 2 HgO(s) 2 Hg( ) + O 2. A(g) + B(g) AB(g) 2 SO 2 (g) + O 2 (g) 2 SO 3 (g)

(3) AgCl(s) Ag + (aq) + Cl (aq) (4) 2 HgO(s) 2 Hg( ) + O 2. A(g) + B(g) AB(g) 2 SO 2 (g) + O 2 (g) 2 SO 3 (g) 1. Given the reaction at equilibrium: H 2 + Cl 2 2 HCl As the pressure s at constant temperature, the number of moles of HCl (1) s (3) remains the same (2) s 2. The Haber process is represented by the

More information

Unit 5 Practice Test. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.

Unit 5 Practice Test. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question. Name: Class: Date: Unit 5 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The internal energy of a system is always increased by. A) adding

More information

Chemistry Distributed Practice Assessment

Chemistry Distributed Practice Assessment Name Hour Chemistry Distributed Practice Assessment Practice 2011 Practice Exam A **This END OF COURSE Practice Exam is a qualifier for all Exam Takers 1 Objective 1 Answer questions relating to atomic

More information

Chemistry Final Exam Review

Chemistry Final Exam Review Name: Date: Block: Chemistry Final Exam Review 2012-2013 Unit 1: Measurement, Numbers, Scientific Notation, Conversions, Dimensional Analysis 1. Write 0.000008732 in scientific notation 8.732x10-6 2. Write

More information

Test Review # 9. Chemistry R: Form TR9.13A

Test Review # 9. Chemistry R: Form TR9.13A Chemistry R: Form TR9.13A TEST 9 REVIEW Name Date Period Test Review # 9 Collision theory. In order for a reaction to occur, particles of the reactant must collide. Not all collisions cause reactions.

More information

Experiment 7: Enthalpy of Formation of Magnesium Oxide

Experiment 7: Enthalpy of Formation of Magnesium Oxide Experiment 7: Enthalpy of Formation of Magnesium Oxide Objective: In this experiment, a simple calorimeter will be constructed and calibrated, and Hess' law of constant heat summation will be used to determine

More information

Chapter 5 Energy Relationships in Chemistry: Thermochemistry

Chapter 5 Energy Relationships in Chemistry: Thermochemistry Chapter 5 Energy Relationships in Chemistry: Thermochemistry In order to study thermochemical changes, we first have to define (a) system that specify part of the universe of interest to us. (b) surrounding

More information

Enthalpy of Neutralization. Introduction

Enthalpy of Neutralization. Introduction Enthalpy of Neutralization Introduction Energy changes always accompany chemical reactions. If energy, in the form of heat, is liberated the reaction is exothermic and if energy is absorbed the reaction

More information

Reading. Spontaneity. Monday, January 30 CHEM 102H T. Hughbanks

Reading. Spontaneity. Monday, January 30 CHEM 102H T. Hughbanks Thermo Notes #3 Entropy and 2nd Law of Thermodynamics Monday, January 30 CHEM 102H T. Hughbanks Reading You should reading Chapter 7. Some of this material is quite challenging, be sure to read this material

More information

Thermodynamics and Equilibrium

Thermodynamics and Equilibrium Chapter 19 Thermodynamics and Equilibrium Concept Check 19.1 You have a sample of 1.0 mg of solid iodine at room temperature. Later, you notice that the iodine has sublimed (passed into the vapor state).

More information

Sample Exercise 15.1 Writing Equilibrium-Constant Expressions

Sample Exercise 15.1 Writing Equilibrium-Constant Expressions Sample Exercise 15.1 Writing Equilibrium-Constant Expressions Write the equilibrium expression for K c for the following reactions: Solution Analyze: We are given three equations and are asked to write

More information

Thermochemistry. Chapter 6. Concept Check 6.1. Concept Check 6.2. Solution

Thermochemistry. Chapter 6. Concept Check 6.1. Concept Check 6.2. Solution Chapter 6 Thermochemistry Concept Check 6.1 A solar-powered water pump has photovoltaic cells on protruding top panels. These cells collect energy from sunlight, storing it momentarily in a battery, which

More information

Rate of Reaction and the Collision Theory. Factors that Affect the Rate of a Chemical Reaction

Rate of Reaction and the Collision Theory. Factors that Affect the Rate of a Chemical Reaction Chemical Kinetics and Thermodynamics Chemical Kinetics- concerned with: 1. Rates of Chemical Reactions- # of moles of reactant used up or product formed Unit time Or 2. Reaction Mechanisms- Rate of Reaction

More information

( )( L L)

( )( L L) Chemistry 360 Dr. Jean M. Standard Problem Set 5 Solutions 1. Determine the amount of pressure-volume work performed by 1 mole of water freezing to ice at 0 C and 1 atm pressure. The density of liquid

More information

STOICHIOMETRY II UNIT

STOICHIOMETRY II UNIT STOICHIOMETRY II UNIT Assignment #1 (Conversions with compounds) 1. Convert 1.806 x 10 23 molecules of Cl2 to moles. 2. Convert 1000 molecules of P4O10 to moles. 3. Convert 360 grams of NH3 (ammonia gas)

More information