Chapter 1 Introduction

Question 1

Thermodynamics can be defined as?

Energy can be viewed as ?

Answer 1

the science of energy

the ability to cause changes

Question 2

in engineering, we use thermodynamics to

Answer 2

understand how energy is transferred from one form to another in order to accomplish a given purpose

Question 3

Some applications where thermodynamics is important

Answer 3

Question 4

Any physical quantity can be characterized

Answer 4

Dimentions

Question 5

The magnitude assigned to dimensions are called

Answer 5

Units

Question 6

Basic dimensions

Answer 6

mass

length

time

temperature

Question 7

secondary dimensions (derived from dimensions ) can be expressed as products of primary dimensions

Answer 7

force

velocity

energy

time

Question 8

SI prefixed

Answer 8

Question 9

Some SI and English Units

Answer 9

Question 10

Work, which is a form of energy transfer, is defined as

Answer 10

force x distance

Question 11

In SI, work has units of

Answer 11

N*m which is also called a joule

1J=1Nm

Question 12

in EE, the force unit is the _______, which imparts an acceleration of 1ft/s² on a mass of 32.174 lbm

Answer 12

in EE, the force unit is the pound-force, which imparts an acceleration of 1ft/s² on a mass of 32.174 lb

1lbf = 32.174 lbm ft/s²

Question 13

in the English system, the energy work unit is ______

the ___ is defined as the energy required to raise the temperature of 1 lbm of water at 68 f by 1 f

the unit of time rate of energy, or power is ______

this unit is given the name ______

Answer 13

Question 14

one foolproof way of converting units is to form_______________ and use them to multiply quantities as necessary

Answer 14

Question 15

Newtons second law

Answer 15

The second law states that the acceleration of an object is dependent upon two variables - the net force acting upon the object and the mass of the object.

F=ma

Question 16

Newton’s second law example

Answer 16

Question 17

There are three types of systems; the types of systems are differentiated by whether or not mass and/or energy can cross the system boundary:

Isolated System:

Closed System:

Open System:

Answer 17

Isolated System: Neither mass nor energy can cross the system boundary.

Closed System: Energy can cross the system boundary, but mass cannot.

Open System: Both mass and energy can cross the system boundary

Question 18

When the system undergoes a change in state, it is undergoing a thermodynamic process. Examples of processes include

Answer 18

When the system undergoes a change in state, it is undergoing a thermodynamic process. Examples of processes include

Heating or cooling.

Compressing or expanding.

Changes as electricity flows across the system boundary

Question 19

A special series of processes is one where, afterward, the system is left at the state where it started.

The series of processes then makes up a thermodynamic cycle.

Devices operating in a cycle can operate indefinitely.

An important example is the cycle utilized in steam power plants, which is called the ___________

Answer 19

Rankine cycle

Question 20

Rankine cycle

Answer 20

Question 21

Define equilibrium

Answer 21

Equilibrium is defined as a state of balance due to the canceling of the action of opposing forces.

Question 22

Mechanical equilibrium

Answer 22

Mechanical equilibrium – there is no change in pressure at any point in the system with time, so there is no fluid motion.

Question 23

Thermal equilibrium

Answer 23

Thermal equilibrium – the temperature is the same throughout the system, so there is no driver for internal heat transfer.

Question 24

Phase equilibrium

Answer 24

Phase equilibrium – the mass of each phase present has reached an equilibrium level and stays there.

Question 25

Chemical equilibrium

Answer 25

Chemical equilibrium – the chemical composition of the system does not change with time. not as important

Question 26

A thermodynamic property is a quantity whose? Examples include

Answer 26

A thermodynamic property is a quantity whose numerical value is independent of how the state of the system was achieved and only depends on the system’s local thermodynamic equilibrium state. pressure P temperature T volume –V mass m

Question 27

Properties can be\_\_\_\_\_ or \_\_\_\_\_\_\_

Answer 27

Properties can be intensive or extensive

Question 28

Intensive properties are those that are

Answer 28

Intensive properties are those that are independent of the mass of the system, like pressure, temperature, and density

Question 29

Extensive properties are those whose value depends on

Answer 29

Extensive properties are those whose value depends on the size – or extent – of the system, like volume and mass.

Question 30

If a uniform system is divided into two equal parts, each part will have the same intensive properties as the original, but its extensive properties will be halved. Intensive properties obtained by taking extensive properties per unit mass are called \_\_\_\_\_\_\_\_\_\_

Answer 30

Question 31

The properties of a substances are related to each other through equations of state. Some equations of state are very simple (any often of limited validity), while others are very complicated so that they can represent known property data. A simple example is **the ideal gas law**

Answer 31

Question 32

Isothermal process – a process during which the Isobaric process – a process during which the Isochoric process or Isometric process – a process during which the

Answer 32

Isothermal process – a process during which the temperature T remains constant. Isobaric process – a process during which the pressure P remains constant. Isochoric process or Isometric process – a process during which the volume –V remains constant.

Question 33

The Zeroth Law of Thermodynamics

Answer 33

The zeroth law of thermodynamics states that if two bodies are each in thermal equilibrium with some third body, then they are also in equilibrium with each other

Question 34

A **pure substance** is a substance that is

Answer 34

A **pure substance** is a substance that is chemically homogeneous – a substance that has uniform chemical composition throughout.

Question 35

A **phase of matter** is a portion of the matter

Answer 35

A **phase of matter** is a portion of the matter of a pure substance that is physically homogeneous

Question 36

When multiple phases are present, they are separated by easily \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Answer 36

When multiple phases are present, they are separated by easily identifiable boundary surfaces.

Question 37

3 primarily phases

Answer 37

primarily the phases solid liquid gas

Question 38

Solids phases (there may be multiple solid phases for one substance) have atoms or molecules\_\_\_\_\_\_ spaced in a fixed lattice structure. These atoms or molecules are held in place by\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_forces. A solid maintains its shape without the aid of a container. As a solid is heated, the molecules will oscillate more and more inside the lattice until they have enough energy to break free. If these molecules form a liquid, we have \_\_\_\_\_\_\_ If they become vapor, we have \_\_\_\_\_\_\_\_\_.

Answer 38

Solids phases (there may be multiple solid phases for one substance) have atoms or molecules closely spaced in a fixed lattice structure. These atoms or molecules are held in place by intermolecular attractive forces . A solid maintains its shape without the aid of a container. As a solid is heated, the molecules will oscillate more and more inside the lattice until they have enough energy to break free. If these molecules form a liquid, we have melting. If they become vapor, we have sublimation.

Question 39

Liquid phases (again, there may be multiple liquid phases, liquid helium has two) also have \_\_\_\_\_\_\_\_\_\_\_\_\_, but they do not maintain a lattice structure. The molecules can translate and rotate. Intermolecular forces are \_\_\_\_\_\_\_\_than in solids, but stronger than in gases. For many liquids, the intermolecular distances increase slightly over the corresponding solid, but in water they \_\_\_\_\_\_. Adding more energy allows the molecules to overcome the intermolecular forces to join the gas phase, and \_\_\_\_\_\_occurs.

Answer 39

Liquid phases (again, there may be multiple liquid phases, liquid helium has two) also have closely spaced molecules, but they do not maintain a lattice structure. The molecules can translate and rotate. Intermolecular forces are weaker than in solids, but stronger than in gases. For many liquids, the intermolecular distances increase slightly over the corresponding solid, but in water they decrease. Adding more energy allows the molecules to overcome the intermolecular forces to join the gas phase, and boiling occurs.

Question 40

Gas molecules move at random, continually colliding with other molecules and with container walls. Particularly at low densities, intermolecular forces are very \_\_\_\_\_\_\_\_\_\_\_\_ are the only mode of interaction between molecules. Molecules in the gas phase are at considerably higher energy than those in a \_\_\_\_\_\_\_, so the gas must release a large amount of its energy before it can condense or \_\_\_\_\_\_. The terms “gas phase” and “vapor phase” both refer to the same phase, but we typically call gases vapor when the substance may also be present as liquid or solid (as with water).

Answer 40

Gas molecules move at random, continually colliding with other molecules and with container walls. Particularly at low densities, intermolecular forces are very small and collisions are the only mode of interaction between molecules. Molecules in the gas phase are at considerably higher energy than those in a liquid or solid, so the gas must release a large amount of its energy before it can condense or freeze. The terms “gas phase” and “vapor phase” both refer to the same phase, but we typically call gases vapor when the substance may also be present as liquid or solid (as with water).

Question 41

phase transitions are the physical processes of transition between ?

Answer 41

phase transitions are the physical processes of transition between a state of a medium, identified by some parameters, and another one, with different values of the parameters.