Thermodynamics - Life and Energy (Lectures 1 and 2)

Question 1

Classical Thermodynamics

Answer 1

deals solely with macroscopic properties and has developed completely independently of molecular and atomic models.

Question 2

Statistical Thermodynamics

Answer 2

Looks into behaviour of matter through the unification of a microscopic and macroscopic approach.

Question 3

3 systems

Answer 3

Open system: can exchange both matter and energy with its surroundings.

Closed system: can exchange energy but not matter with its surroundings.

Isolated system: cannot exchange energy or matter with its surroundings.

Question 4

Energy forms

Answer 4

Heat (g): energy dispersed as random motion.

Work (w): energy dispersed as non random motion.

Question 5

The -1 Law of Thermodynamics

Answer 5

Heat travels from hot to cold.

Question 6

The zero law of Thermodynamics

Answer 6

If ‘A’ and ‘B’ are in thermal equilibrium, and ‘B’ and ‘C’ are in thermal equilibrium then ‘A’ and ‘C’ must also be in thermal equilibrium.

Question 7

Internal energy is shown as

Answer 7

U

measured in Joules.

Question 8

Delta U < 0

Answer 8

energy is lost from the system

Question 9

Delta U > 0

Answer 9

energy is gained from the system

Question 10

CHANGES:
Delta U
dU
aU

Answer 10

Delta U = big change
dU = tiny change
aU = also a tiny change but some variables are kept constant.

Question 11

First law of Thermodynamics

Answer 11

The internal energy of an isolated system is constant.

Question 12

Changes in the internal energy is represented as

Answer 12

Delta U = w + q

always plus, if energy is lost then the overall number is made negative

Question 13

P + V

Answer 13

Pressure and Volume -
Volume expansion against a constant pressure
w = P delta V

Question 14

Enthalpy

Answer 14

Making and breaking bonds

Represented by ‘H’ and is measured in Joules.

Question 15

Delta H = q

Answer 15

Change in enthalpy = energy dispersed in a random motion.

Question 16

Delta H < 0

Answer 16

exothermic process

Question 17

Delta H > 0

Answer 17

endothermic process

Question 18

Spontaneous reactions

Answer 18

Occur naturally - does not require the input of work (energy dispersed in a non-random motion) for it to come about. (Doesn’t mean the process is rapid)

Question 19

Non-spontaneous reactions

Answer 19

Requires work (energy dispersed in a non-random motion) for it to be brought about.

Question 20

Entropy (S)

Answer 20

a measure of disorder representing the unavailable thermal energy in a system.

Question 21

State function

Answer 21

State and the beginning and state at the end matter (in between does not matter)

Question 22

non-state function

Answer 22

the in between state pathway matters (the beginning state and end state do not)

Question 23

The 2nd law of Thermodynamics

Answer 23

The entropy, S, of an isolated system increases for any spontaneous change.
Delta S total > 0.

Question 24

Gibbs Free Energy (G)

Answer 24

Delta G = Delta H - T delta S

expresses the balance between enthalpy and entropy

Question 25

The 3rd Law of Thermodynamics

Answer 25

The entropy of a perfect crystal at the absolute zero of the temperature scale is zero.

Question 26

Standard entropy change

Answer 26

Delta S = Total S product - total S reactants

Question 27

Equilibrium constant

Answer 27

represented by K (the value of Q at equilibrium)

Question 28

reactant/product concentration ratio

Answer 28

represented by Q

Question 29

The universal gal constant

Answer 29

6.314 J K-1

Question 30

To convert to Kelvins

Answer 30

+273 onto the current number