CH6: Second Law of Thermodynamics

Question 1

Lists the function/uses of the second law of thermodynamics

Answer 1

• Identifies the direction of a process
• Asserts the quality/quantity of energy
• Used to determine theoretical limits of a system’s performance
• Predicts degree of completion of chemical reactions
• Illustrates the perfect process

Question 2

List the characteristics of thermal energy reservoirs

Answer 2

• Able to release or absorb amounts of heat without undergoing any change in temperature
• Size of reservoir does not matter, as long as it can pass heat without changing the temperature
• The reservoir thermal capacity&raquo_space; amount of energy supplies/absorbed

Question 3

Name forms of energy

Answer 3

• Mechanical
• Nuclear
• Chemical
• Thermal
• Electromagnetic
• Electrical

Question 4

What is the general rule of performance

Answer 4

Performance = Desire/Require

Question 5

State the Kelvin-Planck Statement

Answer 5

It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work.

Question 6

State the Clausius Statement

Answer 6

It is impossible to construct a device that operates in a cycle and produces no effect other than the transfer of heat from a lower temperature body to a higher temperature body

Question 7

Explain the meaning of reversible process

Answer 7

A process that can be reversed without leaving any trace on the surroundings

Question 8

The meaning of irreversible process

Answer 8

Leaves a net change to the surroundings

Question 9

Which one of the two processes are for idealization?

Answer 9

Reversible process

• easy to analyze
• sets the theoretical limit

Question 10

Which one of the two processes are the reality?

Answer 10

Irreversible process

Question 11

List 3 natural; factors that cause the irreversible process to occur

Answer 11

• Friction
• Mixing of two fluids
• Electric resistance
• Chemical reactions
• Inelastic deformation

Question 12

State the 2 statements known as the Carnot principles

Answer 12

• The efficiency of an irreversible heat engine is always less than the efficiency of a reversible one operating between the same two thermal reservoirs.
• The efficiencies of all reversible heat engines operating between the same two thermal reservoirs are the same.

Question 13

Thermal efficiency of even ideal, reversible engines must be

Answer 13

less than 100%

Question 14

Definition of the thermodynamic temperature scale

Answer 14

A temperature scale that is independent of the properties of the substances

Question 15

The higher the temperature of the thermal energy,

Answer 15

the higher its quality

Question 16

Carnot heat engine is basically which process

Answer 16

Reversible