Definitions

Question 1

Open System

Answer 1

A system which can exchange both energy and matter with its surrounding.

Question 2

Closed System

Answer 2

A system which can exchange energy but not matter across its boundary.

Question 3

Isolated System

Answer 3

A system which can exchange neither energy nor mass with its surrounding.

Question 4

Surrounding

Answer 4

The part of the Universe that isn’t the system, which can interact with the system.

Question 5

Boundary

Answer 5

Anything which separates the system from the surrounding.

Question 6

Intensive properties

Answer 6

Properties of the system that do not depend on the mass of the system. (T, P, C)

Question 7

Extensive properties

Answer 7

Properties of the system that depend on the mass of the system. (V, E, H, S)

Question 8

State variables

Answer 8

The variables which are required to be defined in order to define the state of any system. (P, V, T, U, H, S)

Question 9

State functions

Answer 9

Properties of a system which depend only on the state of the system and not on the path. (U, S, H, A)

Question 10

Process

Answer 10

The path along which a state of a function changes.

Question 11

Isothermal process

Answer 11

A process which takes place at constant T.

Question 12

Isobaric process

Answer 12

A process which takes place at constant P.

Question 13

Isochoric process

Answer 13

A process which takes place at constant V.

Question 14

Adiabetic process

Answer 14

A process during which transfer of heat cannot take place between the system and surrounding.

Question 15

Cyclic process

Answer 15

A process in which the system comes back to its initial state after undergoing a series of changes.

Question 16

Reversible process

Answer 16

A process during which the system always departs infinitesimally from the state of equilibrium.
(It’s direction can be reversed at any moment)

Question 17

Irreversible process

Answer 17

A process during which the system and the surroundings do not return to their original condition once the process is initiated.

Question 18

Zeroth law of thermodynamics

Answer 18

If two thermodynamic systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other.

Question 19

First law of thermodynamics

Answer 19

🔼U = Q + W
🔼U = change in internal E of the system
Q = heat absorbed by the system
W = work done on the system

Question 20

Second law of thermodynamics

Answer 20

The state of entropy of the entire universe, as an isolated system, will always increase over time.

Question 21

Enthalpy

Answer 21

H = U + PV
H = enthalpy
U = internal energy
P = pressure
V = volume

Question 22

Gibbs free energy

Answer 22

🔼G = 🔼H - T🔼S
🔼G = change in Gibbs free energy
🔼H = change in enthalpy
🔼T = temperature in K
🔼S = change in entropy
(the maximum reversible work that is obtained from a particular system)
Constants --> T, P

Question 23

Helmholtz energy

Answer 23

A = U - TS
A = Helmholtz free energy
U = internal energy
T = temperature in K
S = entropy
(the useful work that is obtained from a particular system)
Constants --> T, V

Question 24

Path functions

Answer 24

Properties of a system whose values depend on the transition of the system from the initial state to the final state. (Q, W)

Question 25

Cp

Answer 25

(specific heat at constant pressure)

The amount of energy needed to raise the temperature by 1K at constant P.

Question 26

Cv

Answer 26

(specific heat at constant volume)

The amount of energy needed to raise the temperature by 1K at constant V.