Lecture 1

Question 1

What is a spontaneous change?

Answer 1

changes which occur without an external source of energy
e.g. diamond to graphite, water to ice at 0 degrees, diffusion of gas

Question 2

Describe how entropy changes in spontaneous processes

Answer 2

In spontaneous processes, matter (atoms and molecules) and energy (quanta) become
more disordered
(S is positive)

Question 3

Give the equation for entropy which relates to statistical behaviour of atoms, molecules and quanta

Answer 3

S = k x lnW

S= entropy
k= Boltzmann constant
W= number of microstates

Question 4

What is the 2nd law of thermodynamics?

Answer 4

The entropy of the universe tends to increase.

Question 5

Why is the 2nd law not accurate?

Answer 5

universe is an open system so some entropy decreases

Question 6

Give the definition/equation for entropy change

Answer 6

ΔS= q/T
dS= dq/T

T in kelvin

Question 7

Give the equation to calculate S if T is changing

Answer 7

We have to use an integral;
ΔS= ∫ dS = ∫ dq/T