Thermodynamic Cycle

Question 1

What is the first law of thermodynamics?

Answer 1

Energy cannot be created or destroyed, only transformed.

Question 2

True or False: The second law of thermodynamics states that entropy in a closed system can decrease over time.

Answer 2

False

Question 3

Fill in the blank: The measure of the disorder or randomness in a system is known as ____.

Answer 3

entropy

Question 4

What is the equation for the first law of thermodynamics?

Answer 4

ΔU = Q - W

Question 5

In the context of thermodynamics, what does ‘Q’ represent?

Answer 5

Heat added to the system

Question 6

What does ‘W’ represent in the first law of thermodynamics?

Answer 6

Work done by the system

Question 7

True or False: An isothermal process occurs at constant temperature.

Answer 7

True

Question 8

What is an adiabatic process?

Answer 8

A process in which no heat is exchanged with the surroundings.

Question 9

What is the significance of absolute zero in thermodynamics?

Answer 9

It is the point where molecular motion stops, and entropy reaches its minimum value.

Question 10

What is a Carnot cycle?

Answer 10

A theoretical cycle that provides the maximum possible efficiency for a heat engine.

Question 11

Fill in the blank: The efficiency of a Carnot engine depends only on the temperatures of the ____ and ____ reservoirs.

Answer 11

hot, cold

Question 12

What is the formula for the efficiency of a Carnot engine?

Answer 12

η = 1 - (T_c / T_h)

Question 13

Define ‘enthalpy’.

Answer 13

The total heat content of a system, often represented as H = U + PV.

Question 14

What is Gibbs free energy?

Answer 14

A thermodynamic potential that measures the maximum reversible work obtainable from a closed system at constant temperature and pressure.

Question 15

True or False: A process is spontaneous if it decreases the Gibbs free energy.

Answer 15

True

Question 16

What does the symbol ΔH represent?

Answer 16

Change in enthalpy

Question 17

What is a state function?

Answer 17

A property of a system that depends only on its current state, not on how it reached that state.

Question 18

Fill in the blank: The three laws of thermodynamics are the first law, the second law, and the ____ law.

Answer 18

zeroth

Question 19

What does the zeroth law of thermodynamics state?

Answer 19

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

Question 20

What is the difference between an open and closed system?

Answer 20

An open system can exchange both energy and matter with its surroundings, while a closed system can exchange only energy.

Question 21

What is the unit of heat in the SI system?

Answer 21

Joule (J)

Question 22

Define ‘specific heat capacity’.

Answer 22

The amount of heat required to change the temperature of one unit mass of a substance by one degree Celsius.

Question 23

What is the formula for calculating heat transfer?

Answer 23

Q = mcΔT

Question 24

True or False: The heat capacity of a substance is dependent on the amount of substance present.

Answer 24

True

Question 25

What is thermal conductivity?

Answer 25

The ability of a material to conduct heat.

Question 26

Fill in the blank: In a phase transition, the temperature remains constant while the ____ is added or removed.

Answer 26

heat

Question 27

What is the latent heat of fusion?

Answer 27

The amount of heat required to convert a unit mass of a solid into a liquid at constant temperature.

Question 28

What does the term 'heat engine' refer to?

Answer 28

A device that converts thermal energy into mechanical work.

Question 29

What is the purpose of a heat pump?

Answer 29

To transfer heat from a colder area to a warmer area.

Question 30

Define 'reversible process' in thermodynamics.

Answer 30

A process that can be reversed without leaving any change in the system or surroundings.

Question 31

What is the significance of the Clausius statement of the second law of thermodynamics?

Answer 31

It states that heat cannot spontaneously flow from a colder body to a hotter body.

Question 32

Fill in the blank: The Carnot efficiency is a theoretical limit and cannot be achieved in ____ engines.

Answer 32

real

Question 33

What is the role of a thermodynamic cycle?

Answer 33

To convert energy from one form to another in a systematic way.

Question 34

What is the relationship between pressure, volume, and temperature in an ideal gas?

Answer 34

PV = nRT, where n is the number of moles and R is the ideal gas constant.

Question 35

True or False: An ideal gas is one that perfectly follows the ideal gas law under all conditions.

Answer 35

False

Question 36

What is Boyle's Law?

Answer 36

At constant temperature, the pressure of a gas is inversely proportional to its volume.

Question 37

What is Charles's Law?

Answer 37

At constant pressure, the volume of a gas is directly proportional to its absolute temperature.

Question 38

What is the significance of the Helmholtz free energy?

Answer 38

It measures the useful work obtainable from a system at constant volume and temperature.

Question 39

Fill in the blank: The thermal efficiency of a heat engine is defined as the ratio of ____ to the heat input.

Answer 39

work output

Question 40

What is the relationship between entropy and the direction of spontaneous processes?

Answer 40

Spontaneous processes increase the total entropy of a system and its surroundings.