Chapter 7: Thermochemistry. Contents
|
|
|
- Austin Cain
- 7 years ago
- Views:
Transcription
1 General Chemistry Principles and Modern Applications Petrucci Harwood Herring 9 th Edition Chapter 7: Thermochemistry Dr. Chris Kozak Memorial University of Newfoundland, Canada General Chemistry: Chapter 7 Slide 1 Contents 7-1 Getting Started: Some Terminology 7-2 Heat 7-3 Heats of Reaction and Calorimetry 7-4 Work 7-5 The First Law of Thermodynamics 7-6 Heats of Reaction: U and H 7-7 The Indirect Determination of H: Hess s Law General Chemistry: Chapter 7 Slide 2
2 Contents 7-7 The Indirect Determination of H, Hess s Law 7-8 Standard Enthalpies of Formation 7-9 Fuels as Sources of Energy General Chemistry: Chapter 7 Slide Getting Started: Some Terminology System Surroundings General Chemistry: Chapter 7 Slide 4
3 Terminology Energy, U The capacity to do work. Work Force acting through a distance. Kinetic Energy The energy of motion. General Chemistry: Chapter 7 Slide 5 Energy Kinetic Energy e k = 1 2 mv2 Units: kg m 2 s 2 = J Work w = Fd Units: kg m s 2 m = J General Chemistry: Chapter 7 Slide 6
4 Potential Energy Energy Energy due to condition, position, or composition. Associated with forces of attraction or repulsion between objects. Energy can change from potential to kinetic. General Chemistry: Chapter 7 Slide 7 Energy and Temperature Thermal Energy Kinetic energy associated with random molecular motion. In general proportional to temperature. An intensive property. Heat and Work q and w. Energy changes. General Chemistry: Chapter 7 Slide 8
5 Heat Energy transferred between a system and its surroundings as a result of a temperature difference. Heat flows from hotter to colder. Temperature may change. Phase may change (an isothermal process). General Chemistry: Chapter 7 Slide 9 The Zeroth Law The Law of Thermal Equilibrium If two systems are in thermal equilibrium with a third system, then they must be in thermal equilibrium with each other. This law allows us to define temperature scales and thermometers. Two objects in thermal equilibrium with each other are taken to be the same temperature. General Chemistry: Chapter 7 Slide 10
6 Units of Heat Calorie (cal) The quantity of heat required to change the temperature of one gram of water by one degree Celsius. Joule (J) (Named after James Joule, a brewer) SI unit for heat 1 cal = J General Chemistry: Chapter 7 Slide 11 Heat Capacity The quantity of heat required to change the temperature of a system by one degree. Molar heat capacity (units J mol -1 o C -1 ) System is one mole of substance. Specific heat, c (J g -1 o C -1 ) System is one gram of substance Heat capacity (J o C -1 ) Mass H specific heat. q = mc T q = C T General Chemistry: Chapter 7 Slide 12
7 Conservation of Energy In interactions between a system and its surroundings the total energy remains constant energy is neither created nor destroyed. q system + q surroundings = 0 q system = -q surroundings General Chemistry: Chapter 7 Slide 13 Determination of Specific Heat General Chemistry: Chapter 7 Slide 14
8 Example 7-2 Determining Specific Heat from Experimental Data. Use the data presented on the last slide to calculate the specific heat of lead. q lead = -q water q water = mc T = (50.0 g)(4.184 J/g C)( ) C q water = 1.4x10 3 J q lead = -1.4x10 3 J =mc T = (150.0 g)(c)( ) C c lead = 0.13 Jg -1 C -1 General Chemistry: Chapter 7 Slide 15 Specific Heat Capacities of Some Elements, Compounds, and Materials Substance Specific Heat Capacity (J/g*K) Substance Specific Heat Capacity (J/g*K) Elements Materials aluminum, Al wood 1.76 graphite,c cement 0.88 iron, Fe glass 0.84 copper, Cu granite 0.79 gold, Au steel 0.45 Compounds water, H 2 O(l) ethyl alcohol, C 2 H 5 OH(l) 2.46 ethylene glycol, (CH 2 OH) 2 (l) 2.42 carbon tetrachloride, CCl 4 (l) General Chemistry: Chapter 7 Slide 16
9 7-3 Heats of Reaction and Calorimetry Chemical energy. Contributes to the internal energy of a system. Heat of reaction, q rxn. The quantity of heat exchanged between a system and its surroundings when a chemical reaction occurs within the system, at constant temperature. General Chemistry: Chapter 7 Slide 17 Heats of Reaction Exothermic reactions. Produces heat, q rxn < 0. Endothermic reactions. Consumes heat, q rxn > 0. Calorimeter A device for measuring quantities of heat. General Chemistry: Chapter 7 Slide 18
10 A system transferring energy as heat only. General Chemistry: Chapter 7 Slide 19 Bomb Calorimeter q rxn = -q cal q cal = q bomb + q water + q wires + Define the heat capacity of the calorimeter: q cal = 3m i c i T = C T all i heat General Chemistry: Chapter 7 Slide 20
11 Example 7-3 Using Bomb Calorimetry Data to Determine a Heat of Reaction. The combustion of g sucrose, in a bomb calorimeter, causes the temperature to rise from to C. The heat capacity of the calorimeter assembly is 4.90 kj/ C. (a) What is the heat of combustion of sucrose, expressed in kj/mol C 12 H 22 O 11 (b) Verify the claim of sugar producers that one teaspoon of sugar (about 4.8 g) contains only 19 Calories. Note that 1 food Calorie is actually 1 kcal, so 19 Calories is 19 kcal. General Chemistry: Chapter 7 Slide 21 Example 7-3 Calculate q calorimeter : q cal = C T = (4.90 kj/ C)( ) C = (4.90)(3.41) kj = 16.7 kj Calculate q rxn : q rxn = -q cal = kj per g General Chemistry: Chapter 7 Slide 22
12 Example 7-3 Calculate q rxn in the required units: kj q rxn = -q cal = = kj/g g q rxn g = kj/g 1.00 mol = H 10 3 kj/mol (a) Calculate q rxn for one teaspoon: = (-16.5 kj/g)( q rxn 4.8 g 1 tsp 1.00 kcal )( ) = -19 kcal/tsp kj (b) General Chemistry: Chapter 7 Slide 23 Coffee-cup calorimeter. General Chemistry: Chapter 7 Slide 24
13 Sample Problem: Determining the Heat of a Reaction PROBLEM: You place 50.0 ml of M NaOH in a coffee-cup calorimeter at C and carefully add 25.0 ml of M HCl, also at C. After stirring, the final temperature is C. Calculate q soln (in J). (Assume the total volume is the sum of the individual volumes and that the final solution has the same density and specfic heat capacity as water: d = 1.00 g/ml and c = 4.18 J/g*K) PLAN: Need to determine the limiting reactant from the net ionic equation. Moles of NaOH and HCl as well as the total volume can be calculated. From the volume we use density to find the mass of the water formed. At this point q soln can be calculated using the mass, c, and T. The heat divided by the M of water will give us the heat per mole of water formed. General Chemistry: Chapter 7 Slide 25 Sample Problem Determining the Heat of a Reaction continued SOLUTION: HCl(aq) + NaOH(aq) H + (aq) + OH - (aq) H 2 O(l) NaCl(aq) + H 2 O(l) For NaOH M x L = mol OH - For HCl M x L = mol H + HCl is the limiting reactant mol of H 2 O will form during the rxn. total volume after mixing = L L x10 3 ml/l x 1.00 g/ml = 75.0 g of water q = mass x specific heat x T = 75.0 g x 4.18 J/g* 0 C x ( ) 0 C = 693 J (693 J/ mol H 2 O)(kJ/10 3 J) = 55.4 kj/ mol H 2 O formed General Chemistry: Chapter 7 Slide 26
14 7-4 Work In addition to heat effects chemical reactions may also do work. Gas formed pushes against the atmosphere. Volume changes. Pressure-volume work. General Chemistry: Chapter 7 Slide 27 A system losing energy as work only. Zn(s) + 2H + (aq) + 2Cl - (aq) Energy, E E<0 work done on surroundings H 2 (g) + Zn 2+ (aq) + 2Cl - (aq) General Chemistry: Chapter 7 Slide 28
15 Pressure Volume Work w = F H d = (P H A) H h = P V w = -P ext V General Chemistry: Chapter 7 Slide 29 Example Calculating Pressure-Volume Work. Suppose the gas in the previous figure is mol He at 298 K. How much work, in Joules, is associated with its expansion at constant pressure. Assume an ideal gas and calculate the volume change: V i = nrt/p = (0.100 mol)( L atm mol -1 K -1 )(298K)/(2.40 atm) = 1.02 L V f = 1.88 L V = L = 0.86 L General Chemistry: Chapter 7 Slide 30
16 Example Calculate the work done by the system: w= -P V 101 J = -(1.30 atm)(0.86 L)( ) 1 L atm = -1.1 H 10 2 J Hint: If you use pressure in kpa you get Joules directly. Where did the conversion factor come from? Compare two versions of the gas constant and calculate J mol -1 K L atm mol -1 K J L -1 atm -1 General Chemistry: Chapter 7 Slide The First Law of Thermodynamics Internal Energy, U (some books use E). Total energy (potential and kinetic) in a system (at constant Volume!). Translational kinetic energy. Molecular rotation. Bond vibration. Intermolecular attractions. Chemical bonds. Electrons. General Chemistry: Chapter 7 Slide 32
17 First Law of Thermodynamics A system contains only internal energy. A system does not contain heat or work. These only occur during a change in the system. U = q + w (or E = q + w) Law of Conservation of Energy The energy of an isolated system is constant General Chemistry: Chapter 7 Slide 33 First Law of Thermodynamics Energy entering a system is positive If heat is absorbed by a system, q > 0 If work is done on a system, w > 0 Energy leaving a system is negative If heat is lost by a system, q < 0 If work is done by a system, w < 0 If more energy enters the system, U > 0 If more energy leaves the system, U < 0 General Chemistry: Chapter 7 Slide 34
18 State Functions Any property that has a unique value for a specified state of a system is said to be a State Function. Water at K and 1.00 atm is in a specified state. d = g/ml This density is a unique function of the state. It does not matter how the state was established. General Chemistry: Chapter 7 Slide 35 Functions of State U is a function of state. Not easily measured. U has a unique value between two states. Is easily measured. General Chemistry: Chapter 7 Slide 36
19 Path Dependent Functions Changes in heat and work are not functions of state. Remember example 7-5, w = -1.1 H 10 2 J in a one step expansion of gas: Consider 2.40 atm to 1.80 atm and finally to 1.30 atm. w = (-1.80 atm)( )l (1.30 atm)( )l = L atm 0.68 L atm = -1.3 L atm = (-1.3 L atm)(101 J / 1 L atm) = H 10 2 J General Chemistry: Chapter 7 Slide Heats of Reaction: U and H Reactants Products U i U f U = U f -U i U = q rxn + w In a system at constant volume: U = q rxn + 0 = q rxn = q v But we live in a constant pressure world! How does q p relate to q v? General Chemistry: Chapter 7 Slide 38
20 Heats of Reaction General Chemistry: Chapter 7 Slide 39 Heats of Reaction q V = q P + w We know that w = - P V and U = q V, therefore: U = q P -P V q P = U + P V These are all state functions, so define a new function, Enthalpy. Let H = U + PV Then H = H f H i = U + PV If we work at constant pressure and temperature: H = U + P V = q P General Chemistry: Chapter 7 Slide 40
21 Comparing Heats of Reaction q P = -566 kj/mol = H P V = P(V f V i ) = RT(n f n i ) = -2.5 kj U = H - P V = kj/mol = q V General Chemistry: Chapter 7 Slide 41 Comparing Heats of Reaction U H General Chemistry: Chapter 7 Slide 42
22 Comparing U and H Most chemical reactions involve little or no PV work. In these cases, most or all of the energy change occurs as a transfer of heat. 3 General cases: 1. Reactions that do not involve gases. 2KOH(aq) + H 2 SO 4 (aq) K 2 SO 4 (aq) + 2H 2 O(l) because liquids and solids undergo very small volume changes, V = 0 and P V = 0. Therefore, H U. 2. Reactions in which the amount (or moles) of gases do not change. N 2 (g) + O 2 (g) 2NO(g) when the total amount of gaseous products equals the total amount of gaseous reactants, V = 0 and P V = 0. Therefore, H = U General Chemistry: Chapter 7 Slide 43 Comparing U and H 3. Reactions in which the amount (moles) of gas does change. 2H 2 (g) + O 2 (g) 2H 2 O(g) in this case V is not zero since there are three moles of gas to start and only two at the end. At 25 o C, when two moles of hydrogen and one mole of oxygen produce 2 mol of water vapour, H = kj and P V = nrt = -1 mol x J K -1 mol -1 x 298 K = J = -2.5 kj U = H - P V = kj - (-2.5 kj) = kj P V is small, so U and H are still very close General Chemistry: Chapter 7 Slide 44
23 Changes of State of Matter Consider two endothermic processes: evaporation and melting Molar enthalpy of vaporization: H 2 O (l) H 2 O(g) H vap = 44.0 kj at 298 K Molar enthalpy of fusion: H 2 O (s) H 2 O(l) H fus = 6.01 kj at K If it is for one mole of a substance, then it is called Molar Enthalpy and units are kj mol -1 (needed in discussions of the 2 nd and 3 rd law of thermodynamics) General Chemistry: Chapter 7 Slide 45 Example Enthalpy Changes Accompanying Changes in States of Matter. Calculate H for the process in which 50.0 g of water is converted from liquid at 10.0 C to vapor at 25.0 C. Break the problem into two steps: Raise the temperature of the liquid first then completely vaporize it. The total enthalpy change is the sum of the changes in each step. Set up the equation and calculate: q P = mc H 2O T + n H vap = (50.0 g)(4.184 J/g C)( ) C + = 3.14 kj kj = 125 kj 50.0 g 18.0 g/mol 44.0 kj/mol General Chemistry: Chapter 7 Slide 46
24 Standard States and Standard Enthalpy Changes Define a particular state as a standard state. Standard enthalpy of reaction, H The enthalpy change of a reaction in which all reactants and products are in their standard states. Standard State The pure element or compound at a pressure of 1 bar and at the temperature of interest. General Chemistry: Chapter 7 Slide 47 Enthalpy Diagrams General Chemistry: Chapter 7 Slide 48
25 7-7 Indirect Determination of H: Hess s Law H is an extensive property. Enthalpy change is directly proportional to the amount of substance in a system. N 2 (g) + O 2 (g) 2 NO(g) H = kj ½N 2 (g) + ½O 2 (g) NO(g) H = kj H changes sign when a process is reversed NO(g) ½N 2 (g) + ½O 2 (g) H = kj General Chemistry: Chapter 7 Slide 49 Hess s Law Hess s law of constant heat summation If a process occurs in stages or steps (even hypothetically), the enthalpy change for the overall process is the sum of the enthalpy changes for the individual steps. ½N 2 (g) + ½O 2 (g) NO(g) NO(g) + ½O 2 (g) NO 2 (g) H = kj H = kj ½N 2 (g) + O 2 (g) NO 2 (g) H = kj General Chemistry: Chapter 7 Slide 50
26 Hess s Law Schematically General Chemistry: Chapter 7 Slide 51 Using Hess s Law Two gaseous pollutants that are formed in auto exhaust are CO and NO. An environmental chemist is studying ways to convert them to less harmful gases through the following equation: CO(g) + NO(g) CO 2 (g) + ½N 2 (g) H rxn =? Given the following information, calculate H. CO(g) + 1/2O 2 (g) CO 2 (g) N 2 (g) + O 2 (g) 2NO(g) H = kj H = kj General Chemistry: Chapter 7 Slide 52
27 7-8 Standard Enthalpies of Formation H f The enthalpy change that occurs in the formation of one mole of a substance in the standard state from the reference forms of the elements in their standard states. The standard enthalpy of formation of a pure element in its reference state is 0. General Chemistry: Chapter 7 Slide 53 Standard Enthalpies of Formation General Chemistry: Chapter 7 Slide 54
28 Standard Enthalpies of Formation General Chemistry: Chapter 7 Slide 55 Standard Enthalpies of Reaction H overall = -2 H f NaHCO 3 + H f Na2CO3 + H f CO 2 + H f H2O General Chemistry: Chapter 7 Slide 56
29 Enthalpy of Reaction H rxn = 3 H f products - 3 H f reactants General Chemistry: Chapter 7 Slide 57 Table 7.3 Enthalpies of Formation of Ions in Aqueous Solutions General Chemistry: Chapter 7 Slide 58
30 Determining H o rxn from H o f Nitric Acid, whose worldwide production is nearly 10 billion kg, is used to make many products, including fertilizers, dyes, and explosives. The first step in the process is the oxidation of ammonia: 4NH 3 (g) + 5O 2 (g) 4NO(g) + 6H 2 O(g) Calculate H o rxn from Ho f (from Enthalpy Tables) H o f [NO] = 90.3 kj/mol H o f [H 2O(g)] = kj/mol H o f [NH 3 ] = kj/mol H o f [O 2 ] = 0 kj/mol General Chemistry: Chapter 7 Slide Fuels as Sources of Energy Fossil fuels. Combustion is exothermic. Non-renewable resource. Environmental impact. General Chemistry: Chapter 7 Slide 60
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
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
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
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
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
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
Module 5: Combustion Technology. Lecture 34: Calculation of calorific value of fuels
1 P age Module 5: Combustion Technology Lecture 34: Calculation of calorific value of fuels 2 P age Keywords : Gross calorific value, Net calorific value, enthalpy change, bomb calorimeter 5.3 Calculation
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.
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
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
Thermochemistry I: Endothermic & Exothermic Reactions
THERMOCHEMISTRY I 77 Thermochemistry I: Endothermic & Exothermic Reactions OBJECTIVES: Learn elementary concepts of calorimetry and thermochemistry Practice techniques of careful temperature, mass, and
Chapter 6 Thermodynamics: The First Law
Key Concepts 6.1 Systems Chapter 6 Thermodynamics: The First Law Systems, States, and Energy (Sections 6.1 6.8) thermodynamics, statistical thermodynamics, system, surroundings, open system, closed system,
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
Problem Solving. Stoichiometry of Gases
Skills Worksheet Problem Solving Stoichiometry of Gases Now that you have worked with relationships among moles, mass, and volumes of gases, you can easily put these to work in stoichiometry calculations.
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
Chapter 6 Chemical Calculations
Chapter 6 Chemical Calculations 1 Submicroscopic Macroscopic 2 Chapter Outline 1. Formula Masses (Ch 6.1) 2. Percent Composition (supplemental material) 3. The Mole & Avogadro s Number (Ch 6.2) 4. Molar
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
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
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
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
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
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
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
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 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
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
Experiment 6 Coffee-cup Calorimetry
6-1 Experiment 6 Coffee-cup Calorimetry Introduction: Chemical reactions involve the release or consumption of energy, usually in the form of heat. Heat is measured in the energy units, Joules (J), defined
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
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
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?
HEAT OF FORMATION OF AMMONIUM NITRATE
303 HEAT OF FORMATION OF AMMONIUM NITRATE OBJECTIVES FOR THE EXPERIMENT The student will be able to do the following: 1. Calculate the change in enthalpy (heat of reaction) using the Law of Hess. 2. Find
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 Equations & Stoichiometry
Chemical Equations & Stoichiometry Chapter Goals Balance equations for simple chemical reactions. Perform stoichiometry calculations using balanced chemical equations. Understand the meaning of the term
1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams?
Name: Tuesday, May 20, 2008 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance
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
Chapter 3 Mass Relationships in Chemical Reactions
Chapter 3 Mass Relationships in Chemical Reactions Student: 1. An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative
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
thermometer as simple as a styrofoam cup and a thermometer. In a calorimeter the reactants are placed into the
Thermochemistry Readin assinment: Chan, Chemistry 10 th edition, pp. 249-258. Goals We will become familiar with the principles of calorimetry in order to determine the heats of reaction for endothermic
Chapter 18 Temperature, Heat, and the First Law of Thermodynamics. Problems: 8, 11, 13, 17, 21, 27, 29, 37, 39, 41, 47, 51, 57
Chapter 18 Temperature, Heat, and the First Law of Thermodynamics Problems: 8, 11, 13, 17, 21, 27, 29, 37, 39, 41, 47, 51, 57 Thermodynamics study and application of thermal energy temperature quantity
Chemistry: Chemical Equations
Chemistry: Chemical Equations Write a balanced chemical equation for each word equation. Include the phase of each substance in the equation. Classify the reaction as synthesis, decomposition, single replacement,
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.
The Gas Laws. Our Atmosphere. Pressure = Units of Pressure. Barometer. Chapter 10
Our Atmosphere The Gas Laws 99% N 2 and O 2 78% N 2 80 70 Nitrogen Chapter 10 21% O 2 1% CO 2 and the Noble Gases 60 50 40 Oxygen 30 20 10 0 Gas Carbon dioxide and Noble Gases Pressure Pressure = Force
INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e
CHM111(M)/Page 1 of 5 INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION SECTION A Answer ALL EIGHT questions. (52 marks) 1. The following is the mass spectrum
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
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
PREPARATION FOR CHEMISTRY LAB: COMBUSTION
1 Name: Lab Instructor: PREPARATION FOR CHEMISTRY LAB: COMBUSTION 1. What is a hydrocarbon? 2. What products form in the complete combustion of a hydrocarbon? 3. Combustion is an exothermic reaction. What
Appendix D. Reaction Stoichiometry D.1 INTRODUCTION
Appendix D Reaction Stoichiometry D.1 INTRODUCTION In Appendix A, the stoichiometry of elements and compounds was presented. There, the relationships among grams, moles and number of atoms and molecules
stoichiometry = the numerical relationships between chemical amounts in a reaction.
1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse
Thermochemistry: Calorimetry and Hess s Law
Thermochemistry: Calorimetry and Hess s Law Some chemical reactions are endothermic and proceed with absorption of heat while others are exothermic and proceed with an evolution of heat. The magnitude
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
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).
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
Chapter Three: STOICHIOMETRY
p70 Chapter Three: STOICHIOMETRY Contents p76 Stoichiometry - The study of quantities of materials consumed and produced in chemical reactions. p70 3-1 Counting by Weighing 3-2 Atomic Masses p78 Mass Mass
Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test
Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test NAME Section 7.1 The Mole: A Measurement of Matter A. What is a mole? 1. Chemistry is a quantitative science. What does this term mean?
Heat of Solution. Purpose To calculate the heat of solution for sodium hydroxide (NaOH) and ammonium nitrate (NH 4 NO 3 )
Heat of Solution Purpose To calculate the heat of solution for sodium hydroxide (NaOH) and ammonium nitrate (NH 4 NO 3 ) Background For a given solute, the heat of solution is the change in enerrgy that
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,
Sample Exercise 3.1 Interpreting and Balancing Chemical Equations
Sample Exercise 3.1 Interpreting and Balancing Chemical Equations The following diagram represents a chemical reaction in which the red spheres are oxygen atoms and the blue spheres are nitrogen atoms.
CHEMISTRY. Matter and Change. Section 13.1 Section 13.2 Section 13.3. The Gas Laws The Ideal Gas Law Gas Stoichiometry
CHEMISTRY Matter and Change 13 Table Of Contents Chapter 13: Gases Section 13.1 Section 13.2 Section 13.3 The Gas Laws The Ideal Gas Law Gas Stoichiometry State the relationships among pressure, temperature,
11 Thermodynamics and Thermochemistry
Copyright ç 1996 Richard Hochstim. All rights reserved. Terms of use.» 37 11 Thermodynamics and Thermochemistry Thermodynamics is the study of heat, and how heat can be interconverted into other energy
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) =
Chapter 5, Calculations and the Chemical Equation
1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles
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
Chemistry 151 Final Exam
Chemistry 151 Final Exam Name: SSN: Exam Rules & Guidelines Show your work. No credit will be given for an answer unless your work is shown. Indicate your answer with a box or a circle. All paperwork must
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
Chapter 13. Properties of Solutions
Sample Exercise 13.1 (p. 534) By the process illustrated below, water vapor reacts with excess solid sodium sulfate to form the hydrated form of the salt. The chemical reaction is Na 2 SO 4(s) + 10 H 2
Problem Solving. Percentage Yield
Skills Worksheet Problem Solving Percentage Yield Although we can write perfectly balanced equations to represent perfect reactions, the reactions themselves are often not perfect. A reaction does not
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
AP CHEMISTRY 2009 SCORING GUIDELINES (Form B)
AP CHEMISTRY 2009 SCORING GUIDELINES (Form B) Question 3 (10 points) 2 H 2 O 2 (aq) 2 H 2 O(l) + O 2 (g) The mass of an aqueous solution of H 2 O 2 is 6.951 g. The H 2 O 2 in the solution decomposes completely
Determination of the enthalpy of combustion using a bomb calorimeter TEC
Determination of the enthalpy of TEC Related concepts First law of thermodynamics, Hess s law of constant heat summation, enthalpy of combustion, enthalpy of formation, heat capacity. Principle The bomb
Chapter 8 - Chemical Equations and Reactions
Chapter 8 - Chemical Equations and Reactions 8-1 Describing Chemical Reactions I. Introduction A. Reactants 1. Original substances entering into a chemical rxn B. Products 1. The resulting substances from
Chapter 14 Solutions
Chapter 14 Solutions 1 14.1 General properties of solutions solution a system in which one or more substances are homogeneously mixed or dissolved in another substance two components in a solution: solute
Intermolecular Forces
Intermolecular Forces: Introduction Intermolecular Forces Forces between separate molecules and dissolved ions (not bonds) Van der Waals Forces 15% as strong as covalent or ionic bonds Chapter 11 Intermolecular
Chapter 3: Stoichiometry
Chapter 3: Stoichiometry Key Skills: Balance chemical equations Predict the products of simple combination, decomposition, and combustion reactions. Calculate formula weights Convert grams to moles and
Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.
Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven
THE MOLE / COUNTING IN CHEMISTRY
1 THE MOLE / COUNTING IN CHEMISTRY ***A mole is 6.0 x 10 items.*** 1 mole = 6.0 x 10 items 1 mole = 60, 00, 000, 000, 000, 000, 000, 000 items Analogy #1 1 dozen = 1 items 18 eggs = 1.5 dz. - to convert
Freezing Point Depression: Why Don t Oceans Freeze? Teacher Advanced Version
Freezing Point Depression: Why Don t Oceans Freeze? Teacher Advanced Version Freezing point depression describes the process where the temperature at which a liquid freezes is lowered by adding another
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
Chapter 5 Chemical Quantities and Reactions. Collection Terms. 5.1 The Mole. A Mole of a Compound. A Mole of Atoms.
Chapter 5 Chemical Quantities and Reactions 5.1 The Mole Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500 sheets 1 case = 24 cans 1
Name Class Date. Section: Calculating Quantities in Reactions. Complete each statement below by writing the correct term or phrase.
Skills Worksheet Concept Review Section: Calculating Quantities in Reactions Complete each statement below by writing the correct term or phrase. 1. All stoichiometric calculations involving equations
Bomb Calorimetry. Electrical leads. Stirrer
Bomb Calorimetry Stirrer Electrical leads Oxygen inlet valve Bomb Fuse Calorimeter Outer jacket Not shown: heating and cooling system for outer jacket, and controls that keep the outer jacket at the same
7. 1.00 atm = 760 torr = 760 mm Hg = 101.325 kpa = 14.70 psi. = 0.446 atm. = 0.993 atm. = 107 kpa 760 torr 1 atm 760 mm Hg = 790.
CHATER 3. The atmosphere is a homogeneous mixture (a solution) of gases.. Solids and liquids have essentially fixed volumes and are not able to be compressed easily. have volumes that depend on their conditions,
AS1 MOLES. oxygen molecules have the formula O 2 the relative mass will be 2 x 16 = 32 so the molar mass will be 32g mol -1
Moles 1 MOLES The mole the standard unit of amount of a substance the number of particles in a mole is known as Avogadro s constant (L) Avogadro s constant has a value of 6.023 x 10 23 mol -1. Example
Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.
Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven
Lecture Topics Atomic weight, Mole, Molecular Mass, Derivation of Formulas, Percent Composition
Mole Calculations Chemical Equations and Stoichiometry Lecture Topics Atomic weight, Mole, Molecular Mass, Derivation of Formulas, Percent Composition Chemical Equations and Problems Based on Miscellaneous
Chapter 4. Chemical Composition. Chapter 4 Topics H 2 S. 4.1 Mole Quantities. The Mole Scale. Molar Mass The Mass of 1 Mole
Chapter 4 Chemical Composition Chapter 4 Topics 1. Mole Quantities 2. Moles, Masses, and Particles 3. Determining Empirical Formulas 4. Chemical Composition of Solutions Copyright The McGraw-Hill Companies,
Chapter 13 Chemical Kinetics
Chapter 13 Chemical Kinetics Student: 1. The units of "reaction rate" are A. L mol -1 s -1. B. L 2 mol -2 s -1. C. s -1. D. s -2. E. mol L -1 s -1. 2. For the reaction BrO 3 - + 5Br - + 6H + 3Br 2 + 3H
Mole Notes.notebook. October 29, 2014
1 2 How do chemists count atoms/formula units/molecules? How do we go from the atomic scale to the scale of everyday measurements (macroscopic scale)? The gateway is the mole! But before we get to the
Exam 4 Practice Problems false false
Exam 4 Practice Problems 1 1. Which of the following statements is false? a. Condensed states have much higher densities than gases. b. Molecules are very far apart in gases and closer together in liquids
Chapter 5. Chemical Reactions and Equations. Introduction. Chapter 5 Topics. 5.1 What is a Chemical Reaction
Introduction Chapter 5 Chemical Reactions and Equations Chemical reactions occur all around us. How do we make sense of these changes? What patterns can we find? 1 2 Copyright The McGraw-Hill Companies,
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).
Exp 13 Volumetric Analysis: Acid-Base titration
Exp 13 Volumetric Analysis: Acid-Base titration Exp. 13 video (time: 47:17 minutes) Titration - is the measurement of the volume of a standard solution required to completely react with a measured volume
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry
2. The percent yield is the maximum amount of product that can be produced from the given amount of limiting reactant.
UNIT 6 stoichiometry practice test True/False Indicate whether the statement is true or false. moles F 1. The mole ratio is a comparison of how many grams of one substance are required to participate in
Chapter 10 Temperature and Heat
Chapter 10 Temperature and Heat What are temperature and heat? Are they the same? What causes heat? What Is Temperature? How do we measure temperature? What are we actually measuring? Temperature and Its
IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.
The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole
How To Calculate Mass In Chemical Reactions
We have used the mole concept to calculate mass relationships in chemical formulas Molar mass of ethanol (C 2 H 5 OH)? Molar mass = 2 x 12.011 + 6 x 1.008 + 1 x15.999 = 46.069 g/mol Mass percentage of
Chapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT
Lecture Presentation Chapter 3 Chemical Reactions and Reaction James F. Kirby Quinnipiac University Hamden, CT The study of the mass relationships in chemistry Based on the Law of Conservation of Mass
Worksheet #17. 2. How much heat is released when 143 g of ice is cooled from 14 C to 75 C, if the specific heat capacity of ice is 2.087 J/(g C).
Worksheet #17 Calculating Heat 1. How much heat is needed to bring 12.0 g of water from 28.3 C to 43.87 C, if the specific heat capacity of water is 4.184 /(g? 2. How much heat is released when 143 g of
Gas Laws. The kinetic theory of matter states that particles which make up all types of matter are in constant motion.
Name Period Gas Laws Kinetic energy is the energy of motion of molecules. Gas state of matter made up of tiny particles (atoms or molecules). Each atom or molecule is very far from other atoms or molecules.
AP Chemistry 2005 Scoring Guidelines Form B
AP Chemistry 2005 Scoring Guidelines Form B The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to