# Thermodynamics Heat & Work The First Law of Thermodynamics

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Thermodynamics Heat & Work The First Law of Thermodynamics Lana Sheridan De Anza College April 20, 2016

2 Last time applying the ideal gas equation thermal energy heat capacity phase changes

3 Overview latent heat more about phase changes work, heat, and the first law of thermodynamics P-V diagrams applying the first law in various cases

4 Phase Changes

5 Latent Heat latent heat of fusion, L f The amount of energy (heat) per unit mass required to change a solid to a liquid. Q = ml f where m is the mass of solid that is transformed into a liquid. latent heat of vaporization, L v The amount of energy (heat) per unit mass required to change a liquid to a gas. Q = ml v where m is the mass of liquid that is transformed into a gas.

6 Latent Heat 20 The First Law of Thermodynamics Table 20.2 Latent Heats of Fusion and Vaporization Latent Heat Melting of Fusion Boiling Latent Heat Substance Point ( C) (J/kg) Point ( C) of Vaporization ( J/kg) Helium a Oxygen Nitrogen Ethyl alcohol Water Sulfur Lead Aluminum Silver Gold Copper a Helium does not solidify at atmospheric pressure. The melting point given here corresponds to a pressure of 2.5 MPa. plate melts completely, the change in mass of the water is m f m, which is the mass of new water and is also equal to the initial mass of the ice cube. From the definition of latent heat, and again choosing heat as our energy transfer 1 mechanism, the energy required to change the phase of a pure substance is Table from Serway & Jewett, page 598.

7 Practice The specific heat capacity of ice is about 0.5 cal/g C. Supposing that it remains at that value all the way to absolute zero, calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. How does this number of calories required to change the same gram of 100 C boiling water to 100 C steam? Reminder: 1 cal is the heat required to raise the temperature of 1 g of water by 1 C. 1 Hewitt, Problem 2, page 314.

8 Practice The specific heat capacity of ice is about 0.5 cal/g C. Calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. 1 Hewitt, Problem 2, page 314.

9 Practice The specific heat capacity of ice is about 0.5 cal/g C. Calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. warming ice: melting: Q 1 = mc ice T = (1 g)(0.5 cal/g C)(273 C) = cal Q 2 = ml f = (1 g) warming water: ( ) ( ) J/kg 1 kg = cal J/cal 1000 g Q 3 = mc water T = (1 g)(1.0 cal/g C)(100 C) = 100 cal 1 Hewitt, Problem 2, page 314.

10 Practice The specific heat capacity of ice is about 0.5 cal/g C. Calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. warming ice: melting: Q 1 = mc ice T = (1 g)(0.5 cal/g C)(273 C) = cal Q 2 = ml f = (1 g) warming water: ( ) ( ) J/kg 1 kg = cal J/cal 1000 g Q 3 = mc water T = (1 g)(1.0 cal/g C)(100 C) = 100 cal Total Q 1 + Q 2 + Q 3 = 320 cal. 1 Hewitt, Problem 2, page 314.

11 Practice The specific heat capacity of ice is about 0.5 cal/g C. Supposing that it remains at that value all the way to absolute zero, calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. How does this number of calories required to change the same gram of 100 C boiling water to 100 C steam? 1 Hewitt, Problem 2, page 314.

12 Practice The specific heat capacity of ice is about 0.5 cal/g C. Supposing that it remains at that value all the way to absolute zero, calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. How does this number of calories required to change the same gram of 100 C boiling water to 100 C steam? boiling: Q 4 = ml v = (1 g) ( ) ( ) J/kg 1 kg = 540 cal J/cal 1000 g 1 Hewitt, Problem 2, page 314.

13 Practice The specific heat capacity of ice is about 0.5 cal/g C. Supposing that it remains at that value all the way to absolute zero, calculate the number of calories it would take to change a 1 g ice cube at absolute zero ( 273 C) to 1 g of boiling water. How does this number of calories required to change the same gram of 100 C boiling water to 100 C steam? boiling: Q 4 = ml v = (1 g) ( ) ( ) J/kg 1 kg = 540 cal J/cal 1000 g The energy required to transform the water to steam is much bigger than the energy required to heat the ice, convert it to water, and continue heating up to 100 C. 1 Hewitt, Problem 2, page 314.

14 Question Suppose the same process of adding energy to the ice cube is performed as discussed in the last question, but instead we graph the internal energy of the system as a function of energy input. What would this graph look like? 1 Based on Quick Quiz 20.2, Serway & Jewett, page 600.

15 Practice The heat of vaporizations of ethyl alcohol is about 200 cal/g. If 2 kg of this fluid were allowed to vaporize in a refrigerator, show that 5 kg of ice (at 0 C) would be formed from 0 C water. 1 Hewitt, Problem 8, page 314.

16 Practice The heat of vaporizations of ethyl alcohol is about 200 cal/g. If 2 kg of this fluid were allowed to vaporize in a refrigerator, show that 5 kg of ice (at 0 C) would be formed from 0 C water. Hint: in the last problem we melted 1 g of ice and found it required 80 cal. 1 Hewitt, Problem 8, page 314.

17 Practice The heat of vaporizations of ethyl alcohol is about 200 cal/g. If 2 kg of this fluid were allowed to vaporize in a refrigerator, show that 5 kg of ice (at 0 C) would be formed from 0 C water. Hint: in the last problem we melted 1 g of ice and found it required 80 cal. energy needed for vaporization: Q = ml v,ea = (2 kg)(200 cal/g) = cal assuming this same amount of energy was taken from the water: m = Q L f = cal 80 cal/g = 5000 g = 5 kg 1 Hewitt, Problem 8, page 314.

18 Phase Change paths

19 Evaporation evaporation the process by which a liquid changes to a gas at the liquid surface Since changing from a liquid to a gas requires heat, when a liquid evaporates it takes heat from its surroundings. This is why humans sweat in hot weather, pigs wallow puddles, and dogs pant. All are trying to use evaporation of water to reduce body temperature.

20 Evaporation Ben Franklin noticed that a wet shirt kept him feeling cool on a hot day. He decided to experiment to see if the temperature of objects could be lowered by this process. In 1758 he and John Hadley took a mercury thermometer and repeatedly wet the bulb with ether while using bellows to keep air moving over it. Despite it being a warm day, they recorded temperatures as low as 7 F ( 14 C) at the bulb of the thermometer. This is the basic idea behind refrigeration!

21 Phase Diagrams 1 A typical phase diagram. The dashed green line shows the unusual behavior of water. Diagram by Matthieumarechal, Wikipedia.

22 Liquids below their melting point & above their boiling point Phase changes require the bond structure of the substance to change.

23 Liquids below their melting point & above their boiling point Phase changes require the bond structure of the substance to change. As a liquid is cooled, it will generally start to freeze at one point before another. (Symmetry breaking.) For example, ice cubes in a freezer freeze from the top down. As water freezes solid crystals form and spread throughout. If the water is very pure and cooled without shaking, it can be cooled below 0 C without freezing. This is called supercooling and can happen in some other liquids also under the right conditions.

24 Liquids below their melting point & above their boiling point The same thing can happen when water (or other liquids) are heated just above their boiling points. As the liquid starts to boil, bubbles of vapor form inside it. This happens most easily at defects in the edges of the container. If the container is very smooth and not shaken, the only way the liquid can vaporize is from the middle. Surface tension opposes this. The liquid can be heated a bit above its boiling point. This is called superheating. It is used in bubble chambers to observe charged particles.

25 Heat and Work We now take a closer look at the first law of thermodynamics. We will study thermodynamic systems. These systems are in thermodynamic equilibrium internally. This means that every part of the system will be at the same temperature, and if the system is a gas, it will all be at the same pressure.

26 Heat and Work We now take a closer look at the first law of thermodynamics. We will study thermodynamic systems. These systems are in thermodynamic equilibrium internally. This means that every part of the system will be at the same temperature, and if the system is a gas, it will all be at the same pressure. In particular, for our present discussion we will be considering an ideal gas. (Can use PV = nrt.)

27 Heat and Work Ideal gas clarification. We make the following assumptions in the ideal gas model: the volume of the gas particles is negligible compared to the total gas volume molecules are identical hard spheres (will relax this later) collisions between molecules are elastic there are no intermolecular forces (aside from hard-sphere collisions) there are no long-range forces from the environment (can be relaxed) A real gas is behaves as an idea gas when it is at high temperature and low density (far from condensation).

28 Variables The variables we will use can be broken into types: state variables describe system s state / properties T, P, V, and E int. transfer variables describing energy transferred into our out of the system Q, W

29 Variables The variables we will use can be broken into types: state variables describe system s state / properties T, P, V, and E int. transfer variables describing energy transferred into our out of the system Q, W intensive variables variables that don t change value when the system is doubled in size P, T, ρ, c extensive variables variables that double their value when the system is doubled in size V, E int, m, C

30 ergy is entering or leaving ndary Work represents done a change on a gas given state of the system, Imagine compressing a gas in a piston quasi-statically (meaning er variable. slowly In enough this section, so the gas remains in thermal equilibrium). namic systems, work. Work r 7, and here we investigate gas contained in a cylinder e gas occupies a volume V d on the piston. If the pise exerted by the gas on the he force exerted by the pisiston inward and compress e system to remain essenoint of application of the A iston is pushed downward dy d S r 5 dy j^ (Fig. 20.4b), the rk in Chapter 7, 2PA dy is discussion. Because A dy a b work done on the gas as How much work is done Figure on20.4 the gas? Work is done on 1 (20.8) a gas contained in a cylinder at a Figure form Serway & pressure Jewett. P as the piston is P V

31 rvation process ransfer leaving change system, Work done on a gas ection,. Work stigate ylinder lume V the pison the the pismpress essenof the nward b), the P A V dy Definition of work: W = F dr For this system: W = ( F j) dy j = F dy = P A dy = P dv se A dy gas as (20.8) ositive.. If the a Figure 20.4 Work is done on a gas contained in a cylinder at a pressure P as the piston is pushed downward so that the gas is compressed. b Vf W = P dv V i

32 e gas be Work done on a gas fer variservation a process transfer r leaving Here, the volume decreases, so the work done on the gas is positive. a change e system, s section, rk. Work vestigate cylinder volume V f the pisas on the y the piscompress in essenn of the ownward 0.4b), the ause A dy e gas as (20.8) P A a V dy Figure 20.4 Work is done on a gas contained in a cylinder at a pressure P as the piston is b Work done on a gas Vf W = P dv The work done Von a gas i equals the negative of the area under the PV curve. The area The work is negative donehere is the because area under the the P-V curve volume (with is decreasing, the appropriate resulting sign). in positive work. P f P i P V f f V i i V To e ing I dep at e imp of d cur N PV d T i d F par illu

33 same initial volume, temperature, and pressure, and is assumed to be ideal. In Figure 20.7a, the gas is thermally insulated from its surroundings except at the bottom of Work done depends on the process the gas-filled region, where it is in thermal contact with an energy reservoir. An energy reservoir Different is a source paths of energy or processes that is considered to go from to (V be i, so P great i ) to (V that f, P a finite f ) require transfer of energy to or from the reservoir does not change its temperature. The piston is held different amounts of work. A constant-pressure compression followed by a constant-volume process A constant-volume process followed by a constantpressure compression An arbitrary compression P P P P f f P f f P f f P i V f V i i V P i a b c V f In all of the processes shown above, there are temperature changes during the process. 1 Figure form Serway & Jewett. V i i V P i V f V i i V

34 Heat transfer also depends on the process This process happens at constant temperature: 20.5 The First Law of The gas is initially at temperature T i. The hand reduces its downward force, allowing the piston to move up slowly. The energy reservoir keeps the gas at temperature T i. The g initial tempe T i an conta by a th memb with v above Energy reservoir at T i Energy reservoir at T i a b c Heat Q is transferred to the gas, and the gas does positive work on its surroundings. (Equivalently, negative work is done on the gas.) Figure 20.7 Gas in a cylinder. (a) The gas is in contact with an energy reservoir. The walls of the cylin base in contact with the reservoir is conducting. (b) The gas expands slowly to a larger volume. (c) The half of a volume, with vacuum in the other half. The entire cylinder is perfectly insulating. (d) The gas

35 Heat transfer also depends on the process This process also happens at constant temperature, and has the same start and end points, (V i, P i ) to (V f, P f ): 20.5 The First Law of Thermodynamics 603 The hand reduces its downward force, allowing the piston to move up slowly. The energy reservoir keeps the gas at temperature T i. The gas is initially at temperature T i and contained by a thin membrane, with vacuum above. The membrane is broken, and the gas expands freely into the evacuated region. ir at T i No heat is transferred to the gas, and the gas does no work. c d

36 First Law of Thermodynamics Reminder: Internal energy, E int or U The energy that a system has as a result of its temperature and all other molecular motions, effects, and configurations, when viewed from a reference frame at rest with respect to the center of mass of the system. 1st Law The change in the internal energy of a system is equal to the sum of the heat added to the system and the work done on the system. E int = W + Q This is just the conservation of energy assuming only the internal energy changes.

37 Applying the 1st Law Some special cases of interest: for an isolated system, W = Q = 0 E int = 0 for a process (V i, P i ) to (V i, P i ), a cycle, E int = 0 Q = W

38 Applying the 1st Law: new Vocabulary There are infinitely many paths (V i, P i ) to (V f, P f ) that we might consider. Ones that are of particular interest for modeling systems in engines, etc. are processes that keep a variable constant. There is a technical name for each kind of process that keeps a variable constant.

39 Applying the 1st Law: new Vocabulary Adiabatic process is a process where no heat is transferred into or out of the system. Q = 0 This type of transformation occurs when the gas is in a thermally insulated container, or the process is very rapid, so there is no time for heat transfer. Since Q = 0: E int = W

40 Applying the 1st Law: new Vocabulary Isobaric process is a process that occurs at constant pressure. P i = P = P f This type of transformation occurs when the gas is free to expand or contract by coming into force equilibrium with a constant external environmental pressure. In this case, the expression for work simplifies: W = Vf V i P dv = P(V f V i )

41 Applying the 1st Law: new Vocabulary Isovolumetric process is a process that occurs at constant volume. V i = V = V f In an isovolumetric process the work done is zero, since the volume never changes. W = 0 E int = Q

42 Applying the 1st Law: new Vocabulary Isothermal process is a process that occurs at constant temperature. T i = T = T f This kind of transformation is achieved by putting the system in thermal contact with a large constant-temperature reservoir. In an isothermal process, assuming no change of phase (staying an ideal gas!): E int = 0

43 Isothermal Expansion of an Ideal Gas Since T = 0, PV = nrt reduces to: PV = a where a is a constant. We could also write this as: 606 P = a VChapter 20 The First Law of Thermody Plotting this function: P i P f P i Isotherm PV = constant The curve is a hyperbola. f Isothermal Exp Suppose an ideal g This process is des hyperbola (see App stant indicates that Let s calculate th The work done on t process is quasi-stat V i V f V

44 Isothermal Expansion of an Ideal Gas Since nrt is constant, the work done on the gas in an isothermal expansion is: Vf W = V i Vf P dv nrt = V i V dv ( ) Vf = nrt ln V i ( ) Vi W = nrt ln V f

45 Questions Which path is isobaric? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

46 Questions Which path is isobaric? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D Path D. A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

47 Questions Which path is isothermal? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

48 Questions Which path is isothermal? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D Path C. A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

49 Questions Which path is isovolumetric? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

50 Questions Which path is isovolumetric? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D Path A. A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

51 Questions Which path is adiabatic? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

52 Questions Which path is adiabatic? final state. Figure 20.9 The PV diagram for an isothermal expansion of an ideal gas from an initial state to a P Because T is c n and R: To evaluate th result at the in D Path B. A B C T 1 T 2 T 3 T 4 Figure (Quick Quiz 20.4) Identify the nature of paths A, B, 1 Based on Quick C, Quiz and 20.4, D. Serway & Jewett, page 606. V Numerically, t shown in Figu done on the g the work done Q uick Quiz 2 ric, isotherm

53 Example 20.6: Boiling water This example illustrates how we can apply these ideas to liquids and solids also, and even around phase changes, as long as we are careful. Suppose 1.00 g of water vaporizes isobarically at atmospheric pressure ( Pa). Its volume in the liquid state is V i = V liq = 1.00 cm 3, and its volume in the vapor state is V f = V vap = 1671 cm 3. Find the work done in the expansion and the change in internal energy of the system. Ignore any mixing of the steam and the surrounding air; imagine that the steam simply pushes the surrounding air out of the way.

54 Example 20.6: Boiling water V i = V liq = 1.00 cm 3 V f = V vap = 1671 cm 3 L v = J/kg Work done,

55 Example 20.6: Boiling water V i = V liq = 1.00 cm 3 V f = V vap = 1671 cm 3 L v = J/kg Work done, W = P(V f V i ) = ( Pa)( ) 10 6 m 3 = 169 J Internal energy, E int?

56 Example 20.6: Boiling water V i = V liq = 1.00 cm 3 V f = V vap = 1671 cm 3 L v = J/kg Work done, W = P(V f V i ) = ( Pa)( ) 10 6 m 3 = 169 J Internal energy, E int? Know W, must find Q: Q = L v m = ( J/kg)(1 3 kg) = 2260 J So, E int = W + Q = 2.09 kj

57 Summary latent heat more about phase changes work, heat, and the first law of thermodynamics applying the first law in various cases Homework Serway & Jewett: Read chapter 20 an look at the examples. prev: Ch 20, onward from page 615. OQs: 3, 5, 7; CQs: 3, 11; Probs: 1, 3, 9, 13, 19 new: Ch 20, OQs: 1, 13; Probs: 25, 27, 29, 31, 35, 39, 41, 59, 71, 77

### Answer, Key Homework 6 David McIntyre 1

Answer, Key Homework 6 David McIntyre 1 This print-out should have 0 questions, check that it is complete. Multiple-choice questions may continue on the next column or page: find all choices before making

### 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

### 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

### Thermodynamics AP Physics B. Multiple Choice Questions

Thermodynamics AP Physics B Name Multiple Choice Questions 1. What is the name of the following statement: When two systems are in thermal equilibrium with a third system, then they are in thermal equilibrium

### Phys222 W11 Quiz 1: Chapters 19-21 Keys. Name:

Name:. In order for two objects to have the same temperature, they must a. be in thermal equilibrium.

### THE KINETIC THEORY OF GASES

Chapter 19: THE KINETIC THEORY OF GASES 1. Evidence that a gas consists mostly of empty space is the fact that: A. the density of a gas becomes much greater when it is liquefied B. gases exert pressure

### 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.

### Unit 3: States of Matter Practice Exam

Page 1 Unit 3: States of Matter Practice Exam Multiple Choice. Identify the choice that best completes the statement or answers the question. 1. Two gases with unequal masses are injected into opposite

### 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

### The First Law of Thermodynamics

The First aw of Thermodynamics Q and W are process (path)-dependent. (Q W) = E int is independent of the process. E int = E int,f E int,i = Q W (first law) Q: + heat into the system; heat lost from the

### FUNDAMENTALS OF ENGINEERING THERMODYNAMICS

FUNDAMENTALS OF ENGINEERING THERMODYNAMICS System: Quantity of matter (constant mass) or region in space (constant volume) chosen for study. Closed system: Can exchange energy but not mass; mass is constant

### 13.1 The Nature of Gases. What is Kinetic Theory? Kinetic Theory and a Model for Gases. Chapter 13: States of Matter. Principles of Kinetic Theory

Chapter 13: States of Matter The Nature of Gases The Nature of Gases kinetic molecular theory (KMT), gas pressure (pascal, atmosphere, mm Hg), kinetic energy The Nature of Liquids vaporization, evaporation,

### HEAT UNIT 1.1 KINETIC THEORY OF GASES. 1.1.1 Introduction. 1.1.2 Postulates of Kinetic Theory of Gases

UNIT HEAT. KINETIC THEORY OF GASES.. Introduction Molecules have a diameter of the order of Å and the distance between them in a gas is 0 Å while the interaction distance in solids is very small. R. Clausius

### Type: Single Date: Homework: READ 12.8, Do CONCEPT Q. # (14) Do PROBLEMS (40, 52, 81) Ch. 12

Type: Single Date: Objective: Latent Heat Homework: READ 12.8, Do CONCEPT Q. # (14) Do PROBLEMS (40, 52, 81) Ch. 12 AP Physics B Date: Mr. Mirro Heat and Phase Change When bodies are heated or cooled their

### Introduction to the Ideal Gas Law

Course PHYSICS260 Assignment 5 Consider ten grams of nitrogen gas at an initial pressure of 6.0 atm and at room temperature. It undergoes an isobaric expansion resulting in a quadrupling of its volume.

### 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:

### Study the following diagrams of the States of Matter. Label the names of the Changes of State between the different states.

Describe the strength of attractive forces between particles. Describe the amount of space between particles. Can the particles in this state be compressed? Do the particles in this state have a definite

### The First Law of Thermodynamics

Thermodynamics The First Law of Thermodynamics Thermodynamic Processes (isobaric, isochoric, isothermal, adiabatic) Reversible and Irreversible Processes Heat Engines Refrigerators and Heat Pumps The Carnot

### Name: Class: Date: 10. Some substances, when exposed to visible light, absorb more energy as heat than other substances absorb.

Name: Class: Date: ID: A PS Chapter 13 Review Modified True/False Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true. 1. In all cooling

### KINETIC MOLECULAR THEORY OF MATTER

KINETIC MOLECULAR THEORY OF MATTER The kinetic-molecular theory is based on the idea that particles of matter are always in motion. The theory can be used to explain the properties of solids, liquids,

### Problem Set 1 3.20 MIT Professor Gerbrand Ceder Fall 2003

LEVEL 1 PROBLEMS Problem Set 1 3.0 MIT Professor Gerbrand Ceder Fall 003 Problem 1.1 The internal energy per kg for a certain gas is given by U = 0. 17 T + C where U is in kj/kg, T is in Kelvin, and C

### Energy Matters Heat. Changes of State

Energy Matters Heat Changes of State Fusion If we supply heat to a lid, such as a piece of copper, the energy supplied is given to the molecules. These start to vibrate more rapidly and with larger vibrations

### CHAPTER 14 THE CLAUSIUS-CLAPEYRON EQUATION

CHAPTER 4 THE CAUIU-CAPEYRON EQUATION Before starting this chapter, it would probably be a good idea to re-read ections 9. and 9.3 of Chapter 9. The Clausius-Clapeyron equation relates the latent heat

### a) Use the following equation from the lecture notes: = ( 8.314 J K 1 mol 1) ( ) 10 L

hermodynamics: Examples for chapter 4. 1. One mole of nitrogen gas is allowed to expand from 0.5 to 10 L reversible and isothermal process at 300 K. Calculate the change in molar entropy using a the ideal

### 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

### We will study the temperature-pressure diagram of nitrogen, in particular the triple point.

K4. Triple Point of Nitrogen I. OBJECTIVE OF THE EXPERIMENT We will study the temperature-pressure diagram of nitrogen, in particular the triple point. II. BAKGROUND THOERY States of matter Matter is made

### REASONING AND SOLUTION

39. REASONING AND SOLUTION The heat released by the blood is given by Q cm T, in which the specific heat capacity c of the blood (water) is given in Table 12.2. Then Therefore, T Q cm 2000 J 0.8 C [4186

### FXA 2008. Candidates should be able to : Define and apply the concept of specific heat capacity. Select and apply the equation : E = mcδθ

UNIT G484 Module 3 4.3.3 Thermal Properties of Materials 1 Candidates should be able to : Define and apply the concept of specific heat capacity. Select and apply the equation : E = mcδθ The MASS (m) of

### 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

### 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

### Statistical Mechanics, Kinetic Theory Ideal Gas. 8.01t Nov 22, 2004

Statistical Mechanics, Kinetic Theory Ideal Gas 8.01t Nov 22, 2004 Statistical Mechanics and Thermodynamics Thermodynamics Old & Fundamental Understanding of Heat (I.e. Steam) Engines Part of Physics Einstein

### 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

### 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( )

### 10.7 Kinetic Molecular Theory. 10.7 Kinetic Molecular Theory. Kinetic Molecular Theory. Kinetic Molecular Theory. Kinetic Molecular Theory

The first scheduled quiz will be given next Tuesday during Lecture. It will last 5 minutes. Bring pencil, calculator, and your book. The coverage will be pp 364-44, i.e. Sections 0.0 through.4. 0.7 Theory

### Define the notations you are using properly. Present your arguments in details. Good luck!

Umeå Universitet, Fysik Vitaly Bychkov Prov i fysik, Thermodynamics, 0-0-4, kl 9.00-5.00 jälpmedel: Students may use any book(s) including the textbook Thermal physics. Minor notes in the books are also

### 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

### Kinetic Theory of Gases

Kinetic Theory of Gases Physics 1425 Lecture 31 Michael Fowler, UVa Bernoulli s Picture Daniel Bernoulli, in 1738, was the first to understand air pressure in terms of molecules he visualized them shooting

### Experiment 12E LIQUID-VAPOR EQUILIBRIUM OF WATER 1

Experiment 12E LIQUID-VAPOR EQUILIBRIUM OF WATER 1 FV 6/26/13 MATERIALS: PURPOSE: 1000 ml tall-form beaker, 10 ml graduated cylinder, -10 to 110 o C thermometer, thermometer clamp, plastic pipet, long

### 1.4.6-1.4.8 Gas Laws. Heat and Temperature

1.4.6-1.4.8 Gas Laws Heat and Temperature Often the concepts of heat and temperature are thought to be the same, but they are not. Perhaps the reason the two are incorrectly thought to be the same is because

### ES 106 Laboratory # 2 HEAT AND TEMPERATURE

ES 106 Laboratory # 2 HEAT AND TEMPERATURE Introduction Heat transfer is the movement of heat energy from one place to another. Heat energy can be transferred by three different mechanisms: convection,

### UNIT 6a TEST REVIEW. 1. A weather instrument is shown below.

UNIT 6a TEST REVIEW 1. A weather instrument is shown below. Which weather variable is measured by this instrument? 1) wind speed 3) cloud cover 2) precipitation 4) air pressure 2. Which weather station

### We will try to get familiar with a heat pump, and try to determine its performance coefficient under different circumstances.

C4. Heat Pump I. OBJECTIVE OF THE EXPERIMENT We will try to get familiar with a heat pump, and try to determine its performance coefficient under different circumstances. II. INTRODUCTION II.1. Thermodynamic

### Chem 338 Homework Set #5 solutions October 10, 2001 From Atkins: 5.2, 5.9, 5.12, 5.13, 5.15, 5.17, 5.21

Chem 8 Homework Set #5 solutions October 10, 2001 From Atkins: 5.2, 5.9, 5.12, 5.1, 5.15, 5.17, 5.21 5.2) The density of rhombic sulfur is 2.070 g cm - and that of monoclinic sulfur is 1.957 g cm -. Can

### 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

### So T decreases. 1.- Does the temperature increase or decrease? For 1 mole of the vdw N2 gas:

1.- One mole of Nitrogen (N2) has been compressed at T0=273 K to the volume V0=1liter. The gas goes through the free expansion process (Q = 0, W = 0), in which the pressure drops down to the atmospheric

### EXPERIMENT 15: Ideal Gas Law: Molecular Weight of a Vapor

EXPERIMENT 15: Ideal Gas Law: Molecular Weight of a Vapor Purpose: In this experiment you will use the ideal gas law to calculate the molecular weight of a volatile liquid compound by measuring the mass,

### Rusty Walker, Corporate Trainer Hill PHOENIX

Refrigeration 101 Rusty Walker, Corporate Trainer Hill PHOENIX Compressor Basic Refrigeration Cycle Evaporator Condenser / Receiver Expansion Device Vapor Compression Cycle Cooling by the removal of heat

### = 1.038 atm. 760 mm Hg. = 0.989 atm. d. 767 torr = 767 mm Hg. = 1.01 atm

Chapter 13 Gases 1. Solids and liquids have essentially fixed volumes and are not able to be compressed easily. Gases have volumes that depend on their conditions, and can be compressed or expanded by

### Practice Test. 4) The planet Earth loses heat mainly by A) conduction. B) convection. C) radiation. D) all of these Answer: C

Practice Test 1) Increase the pressure in a container of oxygen gas while keeping the temperature constant and you increase the A) molecular speed. B) molecular kinetic energy. C) Choice A and choice B

### Vaporization of Liquid Nitrogen

Vaporization of Liquid Nitrogen Goals and Introduction As a system exchanges thermal energy with its surroundings, the temperature of the system will usually increase or decrease, depending on the direction

### Materials 10-mL graduated cylinder l or 2-L beaker, preferably tall-form Thermometer

VAPOR PRESSURE OF WATER Introduction At very low temperatures (temperatures near the freezing point), the rate of evaporation of water (or any liquid) is negligible. But as its temperature increases, more

### The final numerical answer given is correct but the math shown does not give that answer.

Note added to Homework set 7: The solution to Problem 16 has an error in it. The specific heat of water is listed as c 1 J/g K but should be c 4.186 J/g K The final numerical answer given is correct but

### Module P7.3 Internal energy, heat and energy transfer

F L E X I B L E L E A R N I N G A P P R O A C H T O P H Y S I C S Module P7.3 Internal energy, heat and energy transfer 1 Opening items 1.1 Module introduction 1.2 Fast track questions 1.3 Ready to study?

### Partner: Jack 17 November 2011. Determination of the Molar Mass of Volatile Liquids

Partner: Jack 17 November 2011 Determination of the Molar Mass of Volatile Liquids Purpose: The purpose of this experiment is to determine the molar mass of three volatile liquids. The liquid is vaporized

### Name Date Class STATES OF MATTER. SECTION 13.1 THE NATURE OF GASES (pages 385 389)

13 STATES OF MATTER SECTION 13.1 THE NATURE OF GASES (pages 385 389) This section introduces the kinetic theory and describes how it applies to gases. It defines gas pressure and explains how temperature

### Chapter 10: Temperature and Heat

Chapter 10: Temperature and Heat 1. The temperature of a substance is A. proportional to the average kinetic energy of the molecules in a substance. B. equal to the kinetic energy of the fastest moving

### 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

### The Second Law of Thermodynamics

The Second aw of Thermodynamics The second law of thermodynamics asserts that processes occur in a certain direction and that the energy has quality as well as quantity. The first law places no restriction

### Chapter 12 - Liquids and Solids

Chapter 12 - Liquids and Solids 12-1 Liquids I. Properties of Liquids and the Kinetic Molecular Theory A. Fluids 1. Substances that can flow and therefore take the shape of their container B. Relative

### A drop forms when liquid is forced out of a small tube. The shape of the drop is determined by a balance of pressure, gravity, and surface tension

A drop forms when liquid is forced out of a small tube. The shape of the drop is determined by a balance of pressure, gravity, and surface tension forces. 2 Objectives Have a working knowledge of the basic

### Chapter 10 Temperature and Heat

Chapter 10 Temperature and Heat GOALS When you have mastered the contents of this chapter, you will be able to achieve the following goals: Definitions Define each of the following terms, and use it an

### TEACHER BACKGROUND INFORMATION THERMAL ENERGY

TEACHER BACKGROUND INFORMATION THERMAL ENERGY In general, when an object performs work on another object, it does not transfer all of its energy to that object. Some of the energy is lost as heat due to

### Specific Heat Capacity and Latent Heat Questions A2 Physics

1. An electrical heater is used to heat a 1.0 kg block of metal, which is well lagged. The table shows how the temperature of the block increased with time. temp/ C 20.1 23.0 26.9 30.0 33.1 36.9 time/s

### 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

### SAM Teachers Guide Heat and Temperature

SAM Teachers Guide Heat and Temperature Overview Students learn that temperature measures average kinetic energy, and heat is the transfer of energy from hot systems to cold systems. They consider what

### Physical Properties of a Pure Substance, Water

Physical Properties of a Pure Substance, Water The chemical and physical properties of a substance characterize it as a unique substance, and the determination of these properties can often allow one to

### 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

### MOLECULAR WEIGHT BY BOILING POINT ELEVATION

MOLECULAR WEIGHT BY BOILING POINT ELEVATION BACKGROUND This experiment demonstrates the use of colligative properties. The goal is to measure the molecular weight of a non-volatile solute by determining

### Kinetic Theory & Ideal Gas

1 of 6 Thermodynamics Summer 2006 Kinetic Theory & Ideal Gas The study of thermodynamics usually starts with the concepts of temperature and heat, and most people feel that the temperature of an object

### LAB 15: HEAT ENGINES AND

251 Name Date Partners LAB 15: HEAT ENGINES AND THE FIRST LAW OF THERMODYNAMICS... the quantity of heat produced by the friction of bodies, whether solid or liquid, is always proportional to the quantity

### Why? Intermolecular Forces. Intermolecular Forces. Chapter 12 IM Forces and Liquids. Covalent Bonding Forces for Comparison of Magnitude

1 Why? Chapter 1 Intermolecular Forces and Liquids Why is water usually a liquid and not a gas? Why does liquid water boil at such a high temperature for such a small molecule? Why does ice float on water?

### States of Matter and the Kinetic Molecular Theory - Gr10 [CAPS]

OpenStax-CNX module: m38210 1 States of Matter and the Kinetic Molecular Theory - Gr10 [CAPS] Free High School Science Texts Project This work is produced by OpenStax-CNX and licensed under the Creative

Chapter 1 Student Reading Chemistry is the study of matter You could say that chemistry is the science that studies all the stuff in the entire world. A more scientific term for stuff is matter. So chemistry

### 7. Gases, Liquids, and Solids 7.1 Kinetic Molecular Theory of Matter

7. Gases, Liquids, and Solids 7.1 Kinetic Molecular Theory of Matter Kinetic Molecular Theory of Matter The Kinetic Molecular Theory of Matter is a concept that basically states that matter is composed

### Online Changing States of Matter Lab Solids What is a Solid? 1. How are solids different then a gas or a liquid?

Name: Period: Online Changing States of Matter Lab Solids What is a Solid? 1. How are solids different then a gas or a liquid? 2. What are the atoms doing in a solid? 3. What are the characteristics of

### 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

### 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

### Experiment 1: Colligative Properties

Experiment 1: Colligative Properties Determination of the Molar Mass of a Compound by Freezing Point Depression. Objective: The objective of this experiment is to determine the molar mass of an unknown

### UNIT (1) MEASUREMENTS IN CHEMISTRY

UNIT (1) MEASUREMENTS IN CHEMISTRY Measurements are part of our daily lives. We measure our weights, driving distances, and gallons of gasoline. As a health professional you might measure blood pressure,

### Chapter 1 Classical Thermodynamics: The First Law. 1.2 The first law of thermodynamics. 1.3 Real and ideal gases: a review

Chapter 1 Classical Thermodynamics: The First Law 1.1 Introduction 1.2 The first law of thermodynamics 1.3 Real and ideal gases: a review 1.4 First law for cycles 1.5 Reversible processes 1.6 Work 1.7

### Phase Diagram of tert-butyl Alcohol

Phase Diagram of tert-butyl Alcohol Bill Ponder Department of Chemistry Collin College Phase diagrams are plots illustrating the relationship of temperature and pressure relative to the phase (or state

### ESSAY. Write your answer in the space provided or on a separate sheet of paper.

Test 1 General Chemistry CH116 Summer, 2012 University of Massachusetts, Boston Name ESSAY. Write your answer in the space provided or on a separate sheet of paper. 1) Sodium hydride reacts with excess

### ES-7A Thermodynamics HW 1: 2-30, 32, 52, 75, 121, 125; 3-18, 24, 29, 88 Spring 2003 Page 1 of 6

Spring 2003 Page 1 of 6 2-30 Steam Tables Given: Property table for H 2 O Find: Complete the table. T ( C) P (kpa) h (kj/kg) x phase description a) 120.23 200 2046.03 0.7 saturated mixture b) 140 361.3

### KINETIC THEORY OF MATTER - molecules in matter are always in motion - speed of molecules is proportional to the temperature

1 KINETIC TERY F MATTER - molecules in matter are always in motion - speed of molecules is proportional to the temperature TE STATES F MATTER 1. Gas a) ideal gas - molecules move freely - molecules have

### Chapter 6 The first law and reversibility

Chapter 6 The first law and reversibility 6.1 The first law for processes in closed systems We have discussed the properties of equilibrium states and the relationship between the thermodynamic parameters

### (1) The size of a gas particle is negligible as compared to the volume of the container in which the gas is placed.

Gas Laws and Kinetic Molecular Theory The Gas Laws are based on experiments, and they describe how a gas behaves under certain conditions. However, Gas Laws do not attempt to explain the behavior of gases.

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

General Chemistry PHS 1015 Practice Exam 4 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements about pressure

### 2. Room temperature: C. Kelvin. 2. Room temperature:

Temperature I. Temperature is the quantity that tells how hot or cold something is compared with a standard A. Temperature is directly proportional to the average kinetic energy of molecular translational

### Chapter 17: Change of Phase

Chapter 17: Change of Phase Conceptual Physics, 10e (Hewitt) 3) Evaporation is a cooling process and condensation is A) a warming process. B) a cooling process also. C) neither a warming nor cooling process.

### Lecture 30 - Chapter 6 Thermal & Energy Systems (Examples) 1

Potential Energy ME 101: Thermal and Energy Systems Chapter 7 - Examples Gravitational Potential Energy U = mgδh Relative to a reference height Increase in elevation increases U Decrease in elevation decreases

### There is no such thing as heat energy

There is no such thing as heat energy We have used heat only for the energy transferred between the objects at different temperatures, and thermal energy to describe the energy content of the objects.

### IDEAL AND NON-IDEAL GASES

2/2016 ideal gas 1/8 IDEAL AND NON-IDEAL GASES PURPOSE: To measure how the pressure of a low-density gas varies with temperature, to determine the absolute zero of temperature by making a linear fit to

### KINETIC THEORY AND THERMODYNAMICS

KINETIC THEORY AND THERMODYNAMICS 1. Basic ideas Kinetic theory based on experiments, which proved that a) matter contains particles and quite a lot of space between them b) these particles always move

### 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 7 Energy and Energy Balances

CBE14, Levicky Chapter 7 Energy and Energy Balances The concept of energy conservation as expressed by an energy balance equation is central to chemical engineering calculations. Similar to mass balances

### 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,

### 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,