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

Save this PDF as:

Size: px
Start display at page:

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

## Transcription

1 CHAPTER 17: THERMOCHEMISTRY Page Heat vs. Temperature ATOM Heat energy= Kinetic energy SUBSTANCE Heat energy = TOTAL Kinetic energy of all atoms in a substance Temperature = AVERAGE Kinetic energy of the atoms in a substance Each atom contains Kinetic energy Like each test has a score All the energy can be added together = amount of heat energy Total points The energy can be averaged= temperature Average of all scores Test Total Average Points Heat vs. Temperature Heat Units: Joule (J) 1KJ = 1000J Units: calories 1Kcal = 1000cal 4.18J = 1cal Temperature Units: Celsius ( C)( or Kelvin (K) Kelvin = C C Heat Capacity vs. Specific Heat q = mc T Heat Capacity (C) J/ C Specific Heat (c) J/g C Table page 508 Water= 4.18J/g C Water= 1.00cal/g C q = heat (J) m = mass (g) c = specific heat (J/g C) T T = change in temperature ( C)( 1

2 Example The temperature of a 95.4g piece of copper increases from 25.0 C C to 48.0 C when the copper absorbs 849J of heat. What is the specific heat of copper. q= m= c= T= 849J/95.4g x 23.0 C C = 0.387J/g C Solving for q Find the amount of heat needed to raise the temperature of 15.0g of water from 25.0 to 35.0 C q = m= c= T= 15.0g x 4.18J/g C C x 10.0 C q= 627J Solving for T How much temperature change would occur if 627J of heat were added to 15.0g of aluminum? Q = m= c= T= 627J/15.0g x 0.90J/g C 46.4 C Thermochemical Equations Include the heat change Include the phase of substances Amount of heat given is for the number of moles of each substance indicated by the coefficients in the equation Why Phase of Substance Must Be Included Decomposition of 1 mole of Water H 2 O (l) H 2(g) + ½O 2(g) H 2 O (g) H 2(g) + ½O 2(g) H=285.8KJ H=241.8KJ difference= 44.0KJ Difference in H H is due to the difference in physical state H 2 O (l) H 2 O (g) H=44.0KJ Exothermic vs. Endothermic Exo = out Endo = within Thermic = pertaining to heat C (s) + O 2(g) CO 2(g) KJ Exothermic or Endothermic 2CuO (s) KJ 2Cu (s) + O 2(g) Exothermic or Endothermic 2

3 Another Way to Write C (s) + O 2(g) CO 2(g) H= KJ Negative (-)( H H = heat is given off by the reaction 2CuO (s) 2Cu (s) + O 2(g) H H = KJ Positive (+) H H = heat is put into the reaction Standard enthalpy of formation ( Hf 0 ) is the heat change that results when one mole of a compound is formed from its elements at a pressure of 1 atm. The standard enthalpy of formation of any element in its most stable form is zero. H 0 (O 2 ) = 0 f H 0 (O 3 ) = 142 kj/mol f H 0 (C, graphite) = 0 f H 0 (C, diamond) = 1.90 kj/mol f 6.6 Enthalpy Change ( H)( Find the heat change for the burning of 25.0g of carbon 1-balanced chemical equation C (s) + O 2(g) CO 2(g) KJ 2-given over g C/1 3-check to see if given is in moles if not convert to moles 25.0g 4-Use mole to energy ratio 6.6 The standard enthalpy of reaction ( Hrxn 0 ) is the enthalpy of a reaction carried out at 1 atm. aa + bb cc + dd H 0 rxn = [ c H 0 f (C) + d H 0 f (D)] - [ a H 0 f (A) + b H 0 f (B)] H 0 rxn = Σ H 0 (products) f - Σ H 0 f (reactants) Hess s Law: When reactants are converted to products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps. (Enthalpy is a state function. It doesn t matter how you get there, only where you start and end.) 6.6 Benzene (C 6 H 6 ) burns in air to produce carbon dioxide and liquid water. How much heat is released per mole of benzene combusted? The standard enthalpy of formation of benzene is kj/mol. 2C 6 H 6 (l) + 15O 2 (g) 12CO 2 (g) + 6H 2 O (l) H 0 rxn = Σ H 0 f(products) - Σ H 0 f(reactants) H 0 rxn = [ 12 H 0 f (CO 6 H 0 2 ) + f (H 2 O) ] - [ 2 H 0 f (C 6 H 6 )] H 0 rxn = [ ] [ ] = kj kj 2 mol = kj/mol C 6 H

4 Chemistry in Action: Fuel Values of Foods and Other Substances C 6 H 12 O 6 (s) + 6O 2 (g) 6CO 2 (g) + 6H 2 O (l) H = kj/mol 1 cal = J 1 Cal = 1000 cal = 4184 J CALORIMETRY Technique to measure amount of heat absorbed or released Calorimeter instrument used for calorimetry Heat & Phase Changes Heat of Fusion & Solidification H fus = - H solid H 2 O (s) H 2 O (l) H 2 O (l) H 2 O (s) H = H H = 6.01KJ/mol H = -6.01KJ/mol Heat of Fusion Problem How many grams of ice at 0 C 0 C will melt if 2.25KJ of heat are added? 1-given over 1 2-use heat of fusion to convert Heat of Vaporization & Condensation H Vap = - H cond H 2 O (l) H 2 O (g) H H = 40.7KJ/mol H 2 O (g) H 2 O (l) H H = -40.7KJ/mol Heat of Vaporization Problem How much heat (in KJ) is absorbed when 24.8g H 2 O (l) at 100 C C and 101.3kPa is converted to steam at 100 C 4

5 What You Need To Know About Water Molar Mass = 18.02g Boiling Point = C Freezing Point= 0.0 C Specific Heat= Heat of fusion= Heat of vaporization 4.18J/g C C or 1cal/g C 6.01 KJ/mol 40.7KJ/mol The enthalpy of solution ( H soln ) is the heat generated or absorbed when a certain amount of solute dissolves in a certain amount of solvent. H soln = H soln - H components Which substance(s) could be used for melting ice? Which substance(s) could be used for a cold pack? Calculating the Enthalpy Change in Solution Formation How much heat (in KJ) is released when 2.500mol NaOH (s) is dissolved in water? List the knowns and the unknown Knowns H soln = KJ/mol (off table) Amount of NaOH (s) dissolved = 2.500mol 6.7 First Law of Thermodynamics Energy can be converted from one form to another but energy cannot be created or destroyed. Second Law of Thermodynamics The entropy of the universe increases in a spontaneous process and remains unchanged in an equilibrium process. Spontaneous process: S univ = S sys + S surr > 0 of Reaction The heat given off by the corrosion reaction of an iron- magnesium alloy with salt water can produce a hot meal. The rate of reaction is increased by adding salt water, so heat is produced rapidly. You will learn some ways in which the rate of a reaction can be increased. Equilibrium process: S univ = S sys + S surr =

6 In chemistry, the rate of chemical change, or the reaction rate, is usually expressed as the amount of reactant changing per unit time. A rate is a measure of the speed of any change that occurs within an interval of time. of chemical reactions are often measured as a change in the number of moles during an interval of time. According to collision theory,, atoms, ions, and molecules can react to form products when they collide with one another, provided that the colliding particles have enough kinetic energy. Effective Collision Ineffective Collision 6

7 The minimum energy that colliding particles must have in order to react is called the activation energy. Energy Diagrams Exothermic Endothermic (a) Activation energy (Ea) for the forward reaction (b) Activation energy (Ea) for the reverse reaction (c) Delta H 50 kj/mol 150 kj/mol -100 kj/mol 300 kj/mol 100 kj/mol +200 kj/mol An activated complex is an unstable arrangement of atoms that forms momentarily at the peak of the activation-energy barrier. The activated complex is sometimes called the transition state. The rate of a chemical reaction depends upon temperature, concentration, particle size, and the use of a catalyst. Animation 22 Explore several factors that control the speed of a reaction. Temperature Storing foods in a refrigerator keeps them fresh longer. Low temperatures slow microbial action. 7

8 Concentration a. In air, a lighted splint glows and soon goes out. b. When placed in pure oxygen (higher oxygen concentration), the splint bursts into flame. Particle Size The minute size of the reactant particles (grain dust), and the mixture of the grain dust with oxygen in the air caused the reaction to be explosive, destroying the grain elevator. Catalysts Simulation 23 Explore the effects of concentration, temperature, and a catalyst on reaction rate. An inhibitor is a substance that interferes with the action of a catalyst. Antioxidants and antimicrobials used in drying fruits and preserving fruit juices slow the action of microbes and limit contact with air. Section Quiz. 8

9 Section Quiz. 1. The units below that would be appropriate to measure the rate of a chemical reaction is mmol/s. mol/l. kj/mol. h/mol. Section Quiz. 2. In a chemical reaction, the energy of reactants is always greater than the energy of the products. more than the activation energy. less than the activation energy. less than the energy of the products. Section Quiz. 3. An increase in which one of the following will NOT increase the reaction rate? temperature concentration of reactants total mass of reactants surface area of reactants Section Quiz. 4. A catalyst works because it lowers the activation energy. increases the temperature. is permanently changed in a reaction. supplies energy to a reaction Reversible Reactions 18.2 Reversible Reactions At chemical equilibrium, no net change occurs in the actual amounts of the components of the system. A reversible reaction is one in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. 9

10 18.2 Reversible Reactions 18.2 Reversible Reactions SO 2 and O 2 react to give SO 3 SO 3 decomposes to SO 2 and O 2 When the rates of the forward and reverse reactions are equal, the reaction has reached a state of balance called chemical equilibrium. The relative concentrations of the reactants and products at equilibrium constitute the equilibrium position of a reaction. At equilibrium, all three types of molecules are present Reversible Reactions Factors Affecting Equilibrium: Le Châtelier âtelier s Principle Stresses that upset the equilibrium of a chemical system include changes in the concentration of reactants or products, changes in temperature,, and changes in pressure. Le Châtelier s principle: : If a stress is applied to a system in dynamic equilibrium, the system changes in a way that relieves the stress. Factors Affecting Equilibrium: Le Châtelier âtelier s Principle Concentration Rapid breathing during and after vigorous exercise helps reestablish the body s s correct CO 2 :H 2 CO 3 equilibrium, keeping the acid concentration in the blood within a safe range. Factors Affecting Equilibrium: Le Châtelier âtelier s Principle 18.2 Temperature Dinitrogen tetroxide is a colorless gas; nitrogen dioxide is a brown gas. The flask on the left is in a dish of hot water; the flask on the right is in ice. 10

11 Factors Affecting Equilibrium: Le Châtelier âtelier s Principle Pressure Pressure affects a mixture of nitrogen, hydrogen, and ammonia at equilibrium Conceptual Problem Conceptual Problem Conceptual Problem 18.2 Section Quiz Section Quiz. 1. In a reaction at equilibrium, reactants and products decrease in concentration. form at equal rates. have equal concentrations. have stopped reacting. 11

12 18.2 Section Quiz. 2. In the reaction 2NO 2 (g) 2NO(g) ) + O 2 (g), increasing the pressure on the reaction would cause the amount of NO to increase. the amount of NO 2 to increase. nothing to happen. the amount of O 2 to increase Section Quiz. 3. Changing which of the following would NOT affect the equilibrium position of a chemical reaction? concentration of a reactant only concentration of a product only temperature only volume only 18.4 Entropy and Free Energy Inside a pile of oily rags or a stack of hay that has not been thoroughly dried, decomposition causes heat to build up. When heat cannot escape, the temperature can become high enough to cause a fire. You will learn about the conditions that will produce a spontaneous chemical reaction. Free Energy and Spontaneous Reactions A spontaneous reaction occurs naturally and favors the formation of products at the specified conditions. Free Energy and Spontaneous Reactions A nonspontaneous reaction is a reaction that does not favor the formation of products at the specified conditions. Photosynthesis is a nonspontaneous reaction that requires an input of energy Free Energy and Spontaneous Free Energy and Spontaneous Reactions Spontaneous reactions produce substantial amounts of products at equilibrium and release free energy. Free energy is energy that is available to do work. 12

13 18.4 Entropy Entropy is a measure of the disorder of a system. Physical and chemical systems attain the lowest possible energy. The law of disorder states that the natural tendency is for systems to move in the direction of maximum disorder or randomness Entropy An increase in entropy favors the spontaneous chemical reaction; a decrease favors the nonspontaneous reaction Entropy For a given substance, the entropy of the gas is greater than the entropy of the liquid or the solid. Similarly, the entropy of the liquid is greater than that of the solid. Entropy Entropy increases when a substance is divided into parts Entropy Entropy tends to increase in chemical reactions in which the total number of product molecules is greater than the total number of reactant molecules Entropy Entropy tends to increase when temperature increases. As the temperature increases, the molecules move faster and faster, which increases the disorder. 13

14 Enthalpy, Entropy, and Free Energy The size and direction of enthalpy changes and entropy changes together determine whether a reaction is spontaneous; that is, whether it favors products and releases free energy. Enthalpy, Entropy, and Free Energy Gibbs Free-Energy Gibbs Free-Energy Gibbs Free-Energy Is the Gibbs free-energy energy change positive or negative in a spontaneous process? The Gibbs free-energy energy change is the maximum amount of energy that can be coupled to another process to do useful work. The numerical value of G is negative in spontaneous processes because the system loses free energy Section Quiz Section Quiz. 1. Free energy from a reaction is the amount of energy that is absorbed by an entropy decrease. equal to the enthalpy change. wasted as heat. available to do work. 14

15 18.4 Section Quiz. 2. Free energy is always available from reactions that are endothermic. nonspontaneous. at equilibrium. spontaneous Section Quiz. 3. Choose the correct words for the spaces: Spontaneous reactions produce and substantial amounts of at equilibrium. free energy, products no free energy, reactants free energy, reactants no free energy, products 18.4 Section Quiz. 4. Which of the following involves a decrease in entropy? Natural gas burns. A liquid freezes. Dry ice sublimes. Water evaporates Section Quiz. 5. A reaction is spontaneous if enthalpy decreases and entropy increases. enthalpy increases and entropy increases. enthalpy decreases and entropy decreases. enthalpy increases and entropy decreases Section Quiz. 6. Choose the correct words for the spaces: Gibbs free-energy energy change is the amount of energy that can be another process to do useful work. maximum, coupled to maximum, duplicated by spontaneous, coupled to minimum, duplicated by END OF SHOW 15

### 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.

### 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

### 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

### 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

### 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

### 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

### 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,

### 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

### 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

### 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

### 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

### 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

### 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.

### 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

### 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

### 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

### 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).

### Name Class Date. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.

Assessment Chapter Test A Chapter: States of Matter In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. The kinetic-molecular

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?

### 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

### Chemistry 110 Lecture Unit 5 Chapter 11-GASES

Chemistry 110 Lecture Unit 5 Chapter 11-GASES I. PROPERITIES OF GASES A. Gases have an indefinite shape. B. Gases have a low density C. Gases are very compressible D. Gases exert pressure equally in all

### Temperature Scales. temperature scales Celsius Fahrenheit Kelvin

Ch. 10-11 Concept Ch. 10 #1, 3, 7, 8, 9, 11 Ch11, # 3, 6, 11 Problems Ch10 # 3, 5, 11, 17, 21, 24, 25, 29, 33, 37, 39, 43, 47, 59 Problems: CH 11 # 1, 2, 3a, 4, 5, 6, 9, 13, 15, 22, 25, 27, 28, 35 Temperature

### 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 14 (MOORE) CHEMICAL EQUILIBRIUM

CHAPTER 14 (MOORE) CHEMICAL EQUILIBRIUM This chapter deals with chemical equilibrium, or how far chemical reactions proceed. Some reactions convert reactants to products with near 100% efficiency but others

### 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

### 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

### 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

### 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

### Chapter 4 Practice Quiz

Chapter 4 Practice Quiz 1. Label each box with the appropriate state of matter. A) I: Gas II: Liquid III: Solid B) I: Liquid II: Solid III: Gas C) I: Solid II: Liquid III: Gas D) I: Gas II: Solid III:

### 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

### AP* Chemistry CHEMICAL EQUILIBRIA: GENERAL CONCEPTS

AP* Chemistry CHEMICAL EQUILIBRIA: GENERAL CONCEPTS THE NATURE OF THE EQUILIBRIUM STATE: Equilibrium is the state where the rate of the forward reaction is equal to the rate of the reverse reaction. At

### 7. 2. KOH (you need an acid or a base, this is a base) 8. 1. 76. All gold atoms have 79 protons and electrons, this is a +3 cation.

IB/SL Chemistry Name ANSWERS Test; Past Chemistry Regents Exams Most Frequently Missed Questions 1. 1. A HIGH PROBABLITY OF FINDING AN ELECTRON 2. 3. +8 (every atom of oxygen in the universe) 3. 2. LOW

### 1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics

Chem 105 Fri 10-23-09 1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics 10/23/2009 1 Please PICK UP your graded EXAM in front.

### 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

### SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS

SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS Rearranging atoms. In a chemical reaction, bonds between atoms in one or more molecules (reactants) break and new bonds are formed with other atoms to

### 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

### Chemical Thermodynamics

Chemical Thermodynamics David A. Katz Department of Chemistry Pima Community College Tucson, AZ 85709, USA First Law of Thermodynamics The First Law of Thermodynamics was expressed in the study of thermochemistry.

### 5. Which temperature is equal to +20 K? 1) 253ºC 2) 293ºC 3) 253 C 4) 293 C

1. The average kinetic energy of water molecules increases when 1) H 2 O(s) changes to H 2 O( ) at 0ºC 3) H 2 O( ) at 10ºC changes to H 2 O( ) at 20ºC 2) H 2 O( ) changes to H 2 O(s) at 0ºC 4) H 2 O( )

### 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

### Answers: Given: No. [COCl 2 ] = K c [CO][Cl 2 ], but there are many possible values for [CO]=[Cl 2 ]

Chemical Equilibrium What are the concentrations of reactants and products at equilibrium? How do changes in pressure, volume, temperature, concentration and the use of catalysts affect the equilibrium

### 5 Answers and Solutions to Text Problems

Energy and States of Matter 5 Answers and Solutions to Text Problems 5.1 At the top of the hill, all of the energy of the car is in the form of potential energy. As it descends down the hill, potential

### 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

### 1. The Kinetic Theory of Matter states that all matter is composed of atoms and molecules that are in a constant state of constant random motion

Physical Science Period: Name: ANSWER KEY Date: Practice Test for Unit 3: Ch. 3, and some of 15 and 16: Kinetic Theory of Matter, States of matter, and and thermodynamics, and gas laws. 1. The Kinetic

### States of Matter CHAPTER 10 REVIEW SECTION 1. Name Date Class. Answer the following questions in the space provided.

CHAPTER 10 REVIEW States of Matter SECTION 1 SHORT ANSWER Answer the following questions in the space provided. 1. Identify whether the descriptions below describe an ideal gas or a real gas. ideal gas

### Chapter 2 Matter and Energy

1 Chapter 2 Matter and Energy Matter Matter is the material that makes up all things is anything that has mass and occupies space is classified as either pure substances or mixtures Pure Substances A pure

### Chemical Reactions - Chapter 2 - Review p #1-23; p. 81 #1-4 Science 8

Name KEY Date Hour Chemical Reactions - Chapter 2 - Review p. 79-80 #1-23; p. 81 #1-4 Science 8 Reviewing Key Terms Choose the letter of the best answer. 1. Which of the following is not a physical property?

### Test 5 Review questions. 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will

Name: Thursday, December 13, 2007 Test 5 Review questions 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will 1. decrease 2. increase 3. remain the same 2. The graph below

### Thermochemistry is study of changes in energy (heat) associated with physical or chemical changes.

Thermochem 1 Thermochemistry Thermochemistry and Energy and Temperature Thermochemistry is study of changes in energy (heat) associated with physical or chemical changes. Force = push F= m a (mass x acceleration)

### Energy Flow in Marine Ecosystem

Energy Flow in Marine Ecosystem Introduction Marin ecosystem is a functional system and consists of living groups and the surrounding environment It is composed of some groups and subgroups 1. The physical

### Kinetic Molecular Theory (con t) Kinetic Molecular Theory Gas Liquid Solid 1. Slightly 2. High 3. Does not expand to

Kinetic Energy and (Kelvin) Temperature Temperature is a Kinetic Energy and (Kelvin) Temperature(2) The Kelvin temperature scale is called the Absolute Zero - Zero degrees on the 1. Highly 2. Low 3. Fills

### 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

### 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) =

### 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)

### Name: Regents Chemistry Review Packet A

Name: Regents Chemistry Review Packet A 1. According to the modern model of the atom, the nucleus of an atom is surrounded by one or more A) electrons B) neutrons A) an alpha particle B) a beta particle

### Equilibrium. Equilibrium 1. Examples of Different Equilibria. K p H 2 + N 2 NH 3 K a HC 2 H 3 O 2 H C 2 H 3 O 2 K sp SrCrO 4 Sr CrO 4

Equilibrium 1 Equilibrium Examples of Different Equilibria K p H 2 + N 2 NH 3 K a HC 2 H 3 O 2 H + - + C 2 H 3 O 2 K sp SrCrO 4 Sr 2+ 2- + CrO 4 Equilibrium deals with: What is the balance between products

### Reading: Moore chapter 18, sections 18.6-18.11 Questions for Review and Thought: 62, 69, 71, 73, 78, 83, 99, 102.

Thermodynamics 2: Gibbs Free Energy and Equilibrium Reading: Moore chapter 18, sections 18.6-18.11 Questions for Review and Thought: 62, 69, 71, 73, 78, 83, 99, 102. Key Concepts and skills: definitions

### 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

### CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING

CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING Essential Standard: STUDENTS WILL UNDERSTAND THAT THE PROPERTIES OF MATTER AND THEIR INTERACTIONS ARE A CONSEQUENCE OF THE STRUCTURE OF MATTER,

### CHEM 105 HOUR EXAM III 28-OCT-99. = -163 kj/mole determine H f 0 for Ni(CO) 4 (g) = -260 kj/mole determine H f 0 for Cr(CO) 6 (g)

CHEM 15 HOUR EXAM III 28-OCT-99 NAME (please print) 1. a. given: Ni (s) + 4 CO (g) = Ni(CO) 4 (g) H Rxn = -163 k/mole determine H f for Ni(CO) 4 (g) b. given: Cr (s) + 6 CO (g) = Cr(CO) 6 (g) H Rxn = -26

### 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?

### 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

### 1. solid, vapor, critical point correct. 2. solid, liquid, critical point. 3. liquid, vapor, critical point. 4. solid, liquid, triple point

mcdonald (pam78654) HW 7B: Equilibria laude (89560) 1 This print-out should have 18 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0

### Energy. Work. Potential Energy. Kinetic Energy. Learning Check 2.1. Energy. Energy. makes objects move. makes things stop. is needed to do work.

Chapter 2 Energy and Matter Energy 2.1 Energy Energy makes objects move. makes things stop. is needed to do work. 1 2 Work Potential Energy Work is done when you climb. you lift a bag of groceries. you

### Chemical Reactions Practice Test

Chemical Reactions Practice Test Chapter 2 Name Date Hour _ Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The only sure evidence for a chemical reaction

### 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

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

### 3.3 Phase Changes Charactaristics of Phase Changes phase change

When at least two states of the same substance are present, scientists describe each different state as a phase. A phase change is the reversible physical change that occurs when a substance changes from

### 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

### 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

### 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

### Q1. A student studied the reaction between dilute hydrochloric acid and an excess of calcium carbonate.

Q. A student studied the reaction between dilute hydrochloric acid and an excess of calcium carbonate. calcium carbonate + hydrochloric acid calcium chloride + water + carbon dioxide The student measured

### Chemistry 13: States of Matter

Chemistry 13: States of Matter Name: Period: Date: Chemistry Content Standard: Gases and Their Properties The kinetic molecular theory describes the motion of atoms and molecules and explains the properties

### R = J/mol K R = L atm/mol K

version: master Exam 1 - VDB/LaB/Spk This MC portion of the exam should have 19 questions. The point values are given with each question. Bubble in your answer choices on the bubblehseet provided. Your

### 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

### 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 3: MATTER & ENERGY

CHAPTER 3: MATTER & ENERGY Problems: 1-50, 57-58, 61-74, 107, 109-115 3.2 What is Matter? Matter: Anything that has mass and occupies volume We study matter at different levels: macroscopic: the level

### q = (mass) x (specific heat) x T = m c T (1)

Experiment: Heat Effects and Calorimetry Heat is a form of energy, sometimes called thermal energy, which can pass spontaneously from an object at a high temperature to an object at a lower temperature.

### Topic 1 National Chemistry Summary Notes. Rates of Reaction

Chemical Reactions Topic 1 National Chemistry Summary Notes Rates of Reaction LI 1, 2 and 3 We know a chemical reaction has taken place when we notice one or more of the following things happening: Colour

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

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

### 1. The graph below represents the potential energy changes that occur in a chemical reaction. Which letter represents the activated complex?

1. The graph below represents the potential energy changes that occur in a chemical reaction. Which letter represents the activated complex? 4. According to the potential energy diagram shown above, the

### Calorimetry: Determining the Heat of Fusion of Ice and the Heat of Vaporization of Liquid Nitrogen - Chemistry I Acc

Calorimetry: Determining the Heat of Fusion of Ice and the Heat of Vaporization of Liquid Nitrogen - Chemistry I Acc O B J E C T I V E 1. Using a simple calorimeter, Determine the heat of fusion of ice

### Problem # 2 Determine the kinds of intermolecular forces present in each element or compound:

Chapter 11 Homework solutions Problem # 2 Determine the kinds of intermolecular forces present in each element or compound: A. Kr B. NCl 3 C. SiH 4 D. HF SOLUTION: Kr is a single atom, hence it can have

### Entropy & Enthalpy Changes A Lab Investigation

Entropy & Enthalpy Changes A Lab Investigation Summary In this investigation, students will explore basic thermodynamic concepts, including spontaneity, entropy, and enthalpy through a series of guided

### Chemical system. Chemical reaction A rearrangement of bonds one or more molecules becomes one or more different molecules A + B C.

Chemical system a group of molecules that can react with one another. Chemical reaction A rearrangement of bonds one or more molecules becomes one or more different molecules A + B C Reactant(s) Product(s)

### Read the sections on Allotropy and Allotropes in your text (pages 464, 475, 871-2, 882-3) and answer the following:

Descriptive Chemistry Assignment 5 Thermodynamics and Allotropes Read the sections on Allotropy and Allotropes in your text (pages 464, 475, 871-2, 882-3) and answer the following: 1. Define the word allotrope

### 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

### 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

### The value of a state function is independent of the history of the system.

1 THERMODYNAMICS - The study of energy in matter - Thermodynamics allows us to predict whether a chemical reaction occurs or not. - Thermodynamics tells us nothing about how fast a reaction occurs. - i.

### 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

### AP Chem Lab 2 Quiz #1 Calorimetry. Conceptual Understanding. Write complete sentences to show your understanding.

AP Chem Lab 2 Quiz #1 Calorimetry Name Conceptual Understanding. Write complete sentences to show your understanding. Differentiate between kinetic energy and potential energy. Energy may be transferred

### 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

### EXPERIMENT 12: Empirical Formula of a Compound

EXPERIMENT 12: Empirical Formula of a Compound INTRODUCTION Chemical formulas indicate the composition of compounds. A formula that gives only the simplest ratio of the relative number of atoms in a compound

### 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

### Chapter 13 The Chemistry of Solids

Chapter 13 The Chemistry of Solids Jeffrey Mack California State University, Sacramento Metallic & Ionic Solids Crystal Lattices Regular 3-D arrangements of equivalent LATTICE POINTS in space. Lattice

### 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

### Review - After School Matter Name: Review - After School Matter Tuesday, April 29, 2008

Name: Review - After School Matter Tuesday, April 29, 2008 1. Figure 1 The graph represents the relationship between temperature and time as heat was added uniformly to a substance starting at a solid

### IB Chemistry. DP Chemistry Review

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