A2- Entropy Flashcards

1
Q

What is entropy?

A

measure of disorder of a system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the units for entropy?

A

J K^-1 Mol^-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does feasible mean?

A

a reaction can occur without interference (other conditions may change this, e.g temperature)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the equation for entropy change?

A

(change in)S = Sproducts - Sreactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the equation for free energy?

A

(change in)G = (change in)H - T(change in)S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why do substances tend more towards disorder?

A

as they are require less energy do are more energetically stable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the feasibility where enthalpy change and entropy change are both -ve

A

always feasible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the feasibility where enthalpy change and entropy change are both +ve

A

feasible at higher temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the feasibility where enthalpy change is +ve and entropy change is -ve

A

never possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the feasibility where enthalpy change is -ve and entropy change is +ve

A

feasible at lower temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What must the value of G be for a reaction to be feasible/spontaneous?

A

0 or below

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the formula to determine the temperature where a reaction becomes feasible/spontaneous?

A

T = (change in)H / (change in)S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can affect entropy change?

A
  • number of moles
  • state
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why can some enthalpically unstable reactions still be spontaneous/feasible?

A

as they are entropically favourable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why might some feasible reactions not occur?

A

activation energy is too high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do you calculate enthalpy change?

A

(sum H products) - (sum H reactants)