3 Thermodynamics

Question 1

Define the following:

Isolated systems
closed systems
open systems

Answer 1

isolated systems: no matter or energy exchanged with surroundings

Closed systems: exchange energy but no matter

open systems: both energy and matter exchanged

Question 2

Define and contrast state and path functions

Answer 2

A state function is a property whose value does not depend on the path taken to reach that specific value. In contrast, functions that depend on the path from two values are call path functions. Both path and state functions are often encountered in thermodynamics.

Work and heat are path functions

Question 3

What is the heat of transformation?

Answer 3

heat absorbed or radiated during a change of phase at a constant temperature and pressure

There is NO change in temperature

Question 4

Define the following

Isothermal processes
Adiabatic processes
Isobaric processes
Isovolumetric processes

Answer 4

Isothermal processes: temperature is constant and change of internal energy is therefore zero

Adiabatic processes: no heat exchanged

Isobaric processes: pressure held constant

Isovolumetric processes: volume held constant and the work done by or on the system is zero