Section 1 - Introduction to Thermo

Question 1

Stat the first law of thermodynamics

Answer 1

An expression of the conservation of energy principle.

Energy is a thermodynamic property (characteristic of a system … changed units (mass per -> moles per) there would be no change in property.

Question 2

State the second law of thermodynamics.

Answer 2

Energy has quality as well as quantity.

Processes occurs in the direction of decreasing quality of energy.

Question 3

Can you prove the laws of thermodynamics through maths?

Answer 3

Mo, only through experimental observations.

Question 4

State the difference between intensive and extensive properties

Answer 4

Intensive properties are independent of the size of the system (temp, pressure, density)

Extensive properties are dependent of the size of the system (mass, volume, energy)

Question 5

State what it means for a system in:

1. ) Mechanical Equilibrium
2. ) Thermal Equilibrium

Answer 5

1. ) There is no change in pressure at any point of the system with time … no movement.
2. ) The temperature is uniform throughout the entire system … no heat transfer.

Question 6

State what it means for a system in:

1. ) Chemical Equilibrium
2. ) Phase Equilibrium

Answer 6

1. ) Chemical composition of the system does not change with time … no chemical reactions.
2. ) There is no net change in the mass of each phase with time … no net evaporation or condensation or solidification.

Question 7

What’s a:

State

State Postulate

Answer 7

The thermodynamic state is the set of thermodynamic properties that describes an equilibrium.

Any two independent intensive thermodynamic properties are sufficient to describe the state of a system containing a single pure substance.

Question 8

Thermodynamic Cycle

Answer 8

A sequence of processes that begins and ends at the same state (no net change of state).

Question 9

What is the zeroth law of thermodynamics?

Answer 9

If two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium.