Week 2

Question 1

Define state

Answer 1

If a system is not undergoing any change, then all properties can be measured or calculated throughout the entire system, meaning that the system’s condition can be perfectly described. This means that we know the state of the system

Question 2

True or False: At any given state, it is guaranteed that all properties of a system have fixed values

Answer 2

True. If one property changes, the state also changes

Question 3

In ________ state, there are no unbalanced potentials within the system (experiences no changes when it is isolated from its surroundings)

Answer 3

Equilibrium

Question 4

Define thermal equilibrium

Answer 4

Temperature is the same throughout the entire system

Question 5

Define mechanical equilibrium

Answer 5

No change in pressure at any point of the system with respect to time (pressure may change due to height, but usually small and disregarded)

Question 6

Define phase equilibrium

Answer 6

If a system involves two phases, it is in phase equilibrium when the mass of each phase reaches an equilibrium level and stays there

Question 7

Define chemical equilibrium

Answer 7

When its chemical composition does not change with time

Question 8

Define state postulate (guaranteed question on the midterm)

Answer 8

The state postulate can be defined as the specific number of properties sufficient to fix a state, not all properties of a state must be specified. The number of properties required to fix the state of a system is given by the state postulate

Question 9

What is the state postulate of a simple compressible system

Answer 9

Two independent, intensive properties: Temperature and pressure (always the case for a simple compressible system)

Question 10

Define process

Answer 10

Any change that a system undergoes from one equilibrium state to another

Question 11

Define path

Answer 11

The series of states through which a system passes during a process

Question 12

True or False: To completely describe a process, all that is needed is to specify the initial and final states of the process, the path it follows, and the interactions with the surroundings

Answer 12

True

Question 13

When a process proceeds in a way that the system remains infinitesimally close to an equilibrium state at all times, it is called a ___________ or ____________ process

Answer 13

Quasi-static, quasi-equilibrium

Question 14

Define quasi-static or quasi-equilibrium processes

Answer 14

A sufficiently slow process that allows the system to adjust itself internally so that the properties in one part of the system do not change any faster than those at other parts

Question 15

True or False: An example of a quasi-equilibrium process would be a compression cylinder moving its piston extremely quickly

Answer 15

False, there would be pressure differences at different areas of the system if the cylinder compressed itself very quickly

Question 16

What are the three “Iso-“ processes

Answer 16

Isothermal, Isobaric, and Isochoric/Isometric processes

Question 17

Define an isothermal process

Answer 17

A process where temperature remains constant

Question 18

Define an isobaric process

Answer 18

A process where pressure remains constant

Question 19

Define an isochoric/isometric process

Answer 19

A process where volume remains constant

Question 20

A system is said to have undergone a _____ if it returns to its initial state at the end of the process

Answer 20

Cycle

Question 21

Define a steady-flow process

Answer 21

A process during which a fluid flows through a control volume steadily. Fluid properties can change from point to point within the control volume, but at any fixed point they remain the same during the entire process. The mass, volume, and total energy of the control volume remain constant during a steady-flow process

Question 22

True or False: If the energy crossing the boundary of a closed system is not heat, it must be work

Answer 22

True, energy can cross the boundary of a closed system only in the form of heat or work

Question 23

The work done per unit time is called _____ and is denoted as _______

Answer 23

Power, Watt (J/s)

Question 24

Define an adiabatic system

Answer 24

A process in which no heat transfer takes place

Question 25

True or False: A quantity that is transferred to or from a system during an interaction is a property

Answer 25

False, the amount of such a quantity depends on more than just the state of the system

Question 26

True or False: Heat and work are energy transfer mechanisms between the system and surroundings

Answer 26

True

Question 27

What are the four similarities between heat and work

Answer 27

1. Both are recognized at the boundaries of a system as they cross the boundaries (i.e., both heat and work are boundary phenomena) 2. Systems possess energy, but not heat or work 3. Both are associated with a process, not a state. Unlike properties, heat or work has no meaning at a state 4. Both are path functions (i.e., their magnitudes depend on the path followed during a process as well as the end states)

Question 28

True or False: Path functions have exact differentials denoted by the symbol 'd'

Answer 28

False, they have inexact differentials denoted by the symbol δ

Question 29

Properties are ______ functions and have exact differentials denoted by the symbol ___

Answer 29

Point, 'd'

Question 30

Define intensive property

Answer 30

A property independent of the mass of a system (T, P)

Question 31

Define extensive property

Answer 31

A property whose values depend on the size or extent of the system (m, V)

Question 32

Define specific property

Answer 32

An extensive property per unit mass (specific volume, specific total energy)

Question 33

Define continuum

Answer 33

The assumption of a continuous, homogeneous matter with no holes. A valid assumption if the size of the system we deal with is large relative to the space between the molecules