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

Save this PDF as:

Size: px
Start display at page:

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

## Transcription

2 5. A coffee-cup calorimeter contains ml of M HCl at 20.3 o C. When 1.82 g zinc metal also at 20.3 o C is added and is allowed to react, the temperature rises to 30.5 o C. What is the heat of reaction per mole of Zn? Assume no heat is lost during the course of the reaction and that the heat capacity and the density of the solution is the same as that of pure water. Zn(s) + 2H + (aq) Zn 2+ (aq) + H 2 (g) We first need to determine if all of the zinc will react. How many ml HCl will we need? 1.82 g Zn x 1 mol Zn x 2 mol H + x 1000 ml = 185 ml g Zn 1 mol Zn mol H + So, HCl is the limiting reagent: n HCl H rxn = -mc T (0.100 L x mol HCl/L) H rxn = -( g)(4.184 J/g o C)(30.5 o C o C) H rxn = -( g)(4.184 J/g o C)(10.2 o C) = kj x 2 mol HCl = kj (0.100 L x mol HCl/L) mol HCl 1 mol Zn mol Zn (If you make the incorrect assumption that Zn is the limiting reagent, you find DH = -156 kj/mol Zn.) 6. Determine H o for the reaction N 2 H 4 (l) + 2H 2 O 2 (l) N 2 (g) + 4H 2 O(l) from these data: Reaction N 2 H 4 (l) + O 2 (g) N 2 (g) + 2H 2 O(l) H 2 (g) + ½ O 2 (g) H 2 O(l) H 2 (g) + O 2 (g) H 2 O 2 (l) H o kj kj kj The first reaction is left alone: N 2 H 4 (l) + O 2 (g) N 2 (g) + 2H 2 O(l) kj Double the second reaction 2(H 2 (g) + ½ O 2 (g) H 2 O(l)) 2( kj) Reverse and double the third rxn: 2(H 2 O 2 (l) H 2 (g) + O 2 (g)) -2( kj) Overall Reaction: N 2 H 4 (l) + O 2 (g) + 2H 2 (g) + O 2 (g) + 2H 2 O 2 (l) N 2 (g) + 2H 2 O(l) + 2H 2 O(l) + 2H 2 (g) + 2O 2 (g) N 2 H 4 (l) + 2H 2 O 2 (l) N 2 (g) + 4H 2 O(l) H o = kj + (2( kj)) +(-2( kj)) = kj 2

3 7. Determine the standard enthalpy of formation of hexane, C 6 H 14 (l), from the information below. Report your result in units of kj per mole of hexane. 2 C 6 H 14 (l) + 19 O 2 (g) 12 CO 2 (g) + 14 H 2 O(l) H o = kj Species H o f, kj mol -1 S o f, J mol -1 K -1 G o f, kj mol -1 O 2 (g) H 2 (g) C(s, graphite) CO 2 (g) H 2 O(l) H 2 O(g) H o rxn = 12 H o f, CO H o f,h2o (2 H o f,c6h H o f,o2) kj = 12( kj) + 14( kj) (2 H o f,c6h (0 kj)) H o f,c6h14 = kj - 12( kj) - 14( kj) = kj/mol C 6 H For the reaction, 2 NO(g) + Cl 2 (g) 2 NOCl(g), H o = kj. At what temperatures do you expect the reaction to be spontaneous: high, low, all, or none? Justify your answer. If we look at the reaction, there are three moles of gas on the reactant side and only two moles of gas on the product side, therefore, we expect the S for this process to be negative. So, we will have a situation where we have a negative H and a negative S. Since G = H - T S, the spontaneity of the reaction will depend on temperature. In order for G to be negative and have a spontaneous reaction, temperature must be low in order for H - T S to remain negative. Therefore, we expect this reaction to be spontaneous at low temperatures. 3

4 Part II. Answer two (2) of problems Clearly mark the problems you do not want graded. 15 points each. 9. The initial rate of the reaction A + B C + D is determined for different initial conditions, with the results listed in the table below. Determine the rate law and the rate constant for the reaction. Experiment [A], M [B], M Initial Rate (Ms -1 ) x x x x 10-3 Comparing reactions 1 and 2: [A] remains constant, but [B] changes by (0.0370/0.0185) = 2 times. The rate changes by (6.75 x 10-4 /3.35 x 10-4 ) = 2.01 times. Since the change in rate is the same as the change in concentration, the reaction must be first order in B. Now comparing reactions 2 and 3: [B] remains constant, but [A] changes by (0.0266/0.0133) = 2 times. The rate changes by (2.70 x 10-3 /6.75 x 10-4 ) = 4.00 times. Since the change in rate is the same as the change in concentration squared, the reaction must be second order in A. Therefore, the rate law must be: Rate = k[a] 2 [B] We can use any experiment to find the value of the rate constant. Let s use experiment 4: k = Rate = 1.35 x 10-3 Ms -1 = 103 M -2 s -1 [A] 2 [B] (0.0266M) 2 (0.0185M) So, the overall rate law is: Rate = 103 M -2 s -1 [A] 2 [B] 4

5 10. Sketch two reaction coordinate diagrams below. For the first diagram, illustrate a generic reaction that is non-spontaneous and fast in the forward direction. For the second, illustrate a generic reaction that is spontaneous and slow in the forward direction. Clearly label your plots. For each diagram, include a brief description of how it satisfies the spontaneity and speed of the reaction requirements. Your diagram for the non-spontaneous and fast reaction should bear some resemblance to the picture below and meet the following requirements: 1) the axes must be labeled, 2) the free energy for the reactants must be less than the free energy of the product so that G is positive (non-spontaneous), 3) the size of the activation barrier (hill) must be present, but relatively small to indicate a fast reaction. Your discussion should point out these items. Your diagram for the spontaneous and slow reaction should bear some resemblance to the picture below and meet the following requirements: 1) the axes must be labeled, 2) the free energy for the reactants must be higher than the free energy of the products so that G is negative (spontaneous), 3) the size of the activation barrier (hill) must be present, and relatively large to indicate a slow reaction. Your discussion should point out these items. 5

6 11. Consider the reaction N 2 O(g) + 2H 2 O(l) NH 4 NO 3 (s) at 298K. Species H o f, kj mol -1 S o f, J mol -1 K -1 G o f, kj mol -1 O 2 (g) H 2 (g) NH 4 NO 3 (s) N 2 O(g) H 2 O(l) H 2 O(g) a. Is the forward reaction exothermic or endothermic? H o rxn = H o f, NH4NO3 ( H o f, N2O + 2 H o f,h2o) H o rxn = kj (82.05 kj+ 2( kj)) H o rxn = +124 kj Since H o is positive, the reaction is endothermic b. What is the value of G o at 298 K? S o rxn = S o f, NH4NO3 (S o f, N2O + 2S o f,h2o) S o rxn = 151.1J/K (219.9J/K + 2(69.91J/K)) S o rxn = -209 J/K G o rxn = H o rxn - T S o rxn = +124kJ 298K(0.209kJ/K) = +186 kj c. Does the reaction occur spontaneously at temperatures above 298 K, below 298 K, both, or neither? Justify your answer. Since H o rxn is positive, and S o rxn is negative, G o rxn will be positive at all temperatures, since G o rxn = H o rxn - T S o rxn = (+) (+)(+) = (+) regardless of temperature. So, the reaction is non-spontaneous at all temperatures. 6

7 Possibly Useful Information G H - T S o C = K q rxn = n H rxn q = mc T Don t eat the yellow snow! q released = -q absorbed Compound Molar Mass (g/mol) Compound Molar Mass (g/mol) H 2 O C 6 H H 2 O CO HCl N 2 H H NH 4 NO N N 2 O O NO Cl NOCl Material Specific Heat Capacity (J/gK) H 2 O (s) H 2 O (l) H 2 O (g) Zn(s)

### 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

### 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:

### 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

### 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

### 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:

### 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

### Thermodynamics- Chapter 19 Schedule and Notes

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

### 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,

### 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

### 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

### 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

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

### Mr. Bracken. Multiple Choice Review: Thermochemistry

Mr. Bracken AP Chemistry Name Period Multiple Choice Review: Thermochemistry 1. If this has a negative value for a process, then the process occurs spontaneously. 2. This is a measure of how the disorder

### 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

### 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

### Chemical Reactions: Energy, Rates and Equilibrium

Chemical Reactions: Energy, Rates and Equilibrium Chapter 7 Heat Changes During Chemical Reactions Bond Dissociation Energy- The amount of energy that must be supplied to break a bond and separate the

### 7. Consider the reaction coordinate diagram shown. Which statement is true? C D

SPRING 2001 FINAL 1. A solution prepared by dissolving 6.54 g of a non-volatile solute in 60.0 g of water boils at 100.37 C. What is the approximate molar mass of the solute? K b of H 2 O = 0.512 C/m.

### 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

### 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,

### 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

### 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

### 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

### 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

### CHEM 1332 CHAPTER 14

CHEM 1332 CHAPTER 14 1. Which is a proper description of chemical equilibrium? The frequencies of reactant and of product collisions are identical. The concentrations of products and reactants are identical.

### 2. Predict which of the following spontaneous reactions increase the entropy of the system.

Spontaneity and Entropy DCI Name Section 1. Entropy (S) is a second driving force for chemical reactions. Define the word entropy. How is the sign of S for a chemical reaction interpreted? Entropy is a

### 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

### 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

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?

### 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

### 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

### 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

### 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

### 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.

### 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

### 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?

### 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

### 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

### 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

### 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

### 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

### CHEM1101 Answers to Problem Sheet 8. where c is the specific heat capacity a property of the substance involved.

CEM1101 Answers to Problem Sheet 8 1. The energy q, required to heat a substance of mass m by a temperature ΔT is given by the equation: q = c m ΔT where c is the specific heat capacity a property of the

### 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

### 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

### 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.

### 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

### 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

### 2. A process that releases heat into the surroundings is called. A process that can be reversed by an infinitesimal change in a parameter

Sample quiz and test questions Chapter 2. I. Terms and short answers 1. A system that can exchange neither matter nor energy with its surroundings is called isolated 2. A process that releases heat into

### 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

### CHEMICAL EQUILIBRIUM (ICE METHOD)

CHEMICAL EQUILIBRIUM (ICE METHOD) Introduction Chemical equilibrium occurs when opposing reactions are proceeding at equal rates. The rate at which the products are formed from the reactants equals the

### Chapter 7 Energy and Chemical Change: Breaking and Making Bonds

Multiple Choice Chapter 7 Energy and Chemical Change: Breaking and Making Bonds Section 7.1 1. Which one of the following is a unit of energy, but not an SI unit of energy? a. joule b. newton c. pascal

### 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

### 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

### 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

### 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

### Chem. 1A Final Exam Review Problems From ch. 11, 12 & 13

Chem. A Final Exam Review Problems From ch., 2 & 3 f Multiple Choice Identify the choice that best completes the statement or answers the question.. Place the following cations in order from lowest to

### 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

### Chem 201 Exam Study Questions page 1 Thermodynamics

Chem 201 Exam Study Questions page 1 You will need to use a Table of thermodynamic values to answer some of these questions. A Table of these like that given with the exams is included at the end of this

### Introductory Chemistry, 3 rd Edition Nivaldo Tro. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l

Introductory Chemistry, 3 rd Edition Nivaldo Tro Quantities in Car an octane and oxygen molecules and carbon dioxide and water Chemical Reactions Roy Kennedy Massachusetts Bay Community College Wellesley

### 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

### 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

### A k 1. At equilibrium there is no net change in [A] or [B], namely d[a] dt

Chapter 15: Chemical Equilibrium Key topics: Equilibrium Constant Calculating Equilibrium Concentrations The Concept of Equilibrium Consider the reaction A k 1 k 1 B At equilibrium there is no net change

### 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

### CHEMICAL EQUILIBRIUM

Chemistry 10 Chapter 14 CHEMICAL EQUILIBRIUM Reactions that can go in both directions are called reversible reactions. These reactions seem to stop before they go to completion. When the rate of the forward

### 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.

### 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

### CHM111 Lab Enthalpy of Hydration of Sodium Acetate Grading Rubric

Name Team Name CHM111 Lab Enthalpy of Hydration of Sodium Acetate Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Safety and proper

### Chemistry 12 Unit 2- Equilibrium Notes

Chemistry 12 Unit 2- Equilibrium Notes It's important to know that many chemical reactions are reversible. That is: Reactants Products or Reactants Products Reactants form Products Products form Reactants

### Problems - Chapter 14 (with solutions)

Problems - Chapter 14 (with solutions) 1) Define the following terms: a) catalyst - A substance that speeds up the rate of a reaction without itself being consumed or produced. b) half-life - The time

### MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Given: 4 NO2(g) + O2(g) 2 N2O5(g) ΔH = -110.2 kj find ΔH for N2O5(g) 2 NO2(g) + 1/2 O2(g).

### 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

### 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

### DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3

DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 Standard Enthalpy Change Standard Enthalpy Change for a reaction, symbolized as H 0 298, is defined as The enthalpy change when the molar quantities of reactants

### Chapter 13. Chemical Equilibrium

Chapter 13 Chemical Equilibrium Chapter 13 Preview Chemical Equilibrium The Equilibrium condition and constant Chemical equilibrium, reactions, constant expression Equilibrium involving Pressure Chemical

### Chemistry 212 EXAM 1 January 27, 2004

1 Chemistry 212 EXAM 1 January 27, 2004 _100 (of 100) KEY Name Part 1: Multiple Choice. (1 point each, circle only one answer, 1. Consider the following rate law: Rate = k[a] n [B] m How are the exponents

### Example: orange juice from frozen concentrate.

Dilution: a process in which the concentration (molarity) of a solution is lowered. The amount of solute (atoms, moles, grams, etc.) remains the same, but the volume is increased by adding more solvent.

### 1. How many of the following compounds will exhibit hydrogen bonding?

Spring 2002 Test 1 1. ow many of the following compounds will exhibit hydrogen bonding? N A. 1 B. 2 C. 3 D. 4 E. 5 N C 3 Cl N N C O OC 2 C 2 O 2. Which of the following is indicative of the existence of

### 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

### Gas Phase Equilibrium

Gas Phase Equilibrium Chemical Equilibrium Equilibrium Constant K eq Equilibrium constant expression Relationship between K p and K c Heterogeneous Equilibria Meaning of K eq Calculations of K c Solving

### 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

### Thermodynamics explores the connection between energy and the EXTENT of a reaction but does not give information about reaction rates (Kinetics).

Thermodynamics explores the connection between energy and the EXTENT of a reaction but does not give information about reaction rates (Kinetics). Rates of chemical reactions are controlled by activation

### CHEM 36 General Chemistry EXAM #1 February 13, 2002

CHEM 36 General Chemistry EXAM #1 February 13, 2002 Name: Serkey, Anne INSTRUCTIONS: Read through the entire exam before you begin. Answer all of the questions. For questions involving calculations, show

### 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

### 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

### 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) =

### ENERGY AND CHEMICAL CHANGE 26 AUGUST 2014

ENERGY ND CHEMICL CHNGE 26 UGUST 2014 In this lesson we: Lesson Description Explain energy change in chemical reactions Define exothermic and endothermic reactions Define bond energy Discuss change in

### 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

### 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.

### 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

### 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

### Chemical Equilibrium

Chapter 13 Chemical Equilibrium Equilibrium Physical Equilibrium refers to the equilibrium between two or more states of matter (solid, liquid and gas) A great example of physical equilibrium is shown

### Chapter 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make?

Chapter 15: Chemical Equilibrium: How Much Product Does a Reaction Really Make? End-of-Chapter Problems: 15.1-15.10, 15.13-15.14, 15.17-15.99, 15.102-15.104 Example: Ice melting is a dynamic process: H

### CHEM J-9 June 2014

CHEM1101 2014-J-9 June 2014 The Second Law states that all observable processes must involve a net increase in entropy. When liquid water freezes into ice at 0 C, the entropy of the water decreases. Since

### 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

### 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

### 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

### 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

### 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

### 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.