(BLUE) Entropy

Question 1

What is entropy

Answer 1

Is a property of matter that is associated with the degree of disorder , or degree of randomness of the partials

We can measure the amount of entropy as the amount of disorder in a system , more disorder more entropy

Question 2

What is the third law of thermodynamics dynamics

Answer 2

The entropy of a perfect crystalline substance at 0 K is zero (impossible to achieve)

Question 3

What are the units and definition of the standard molar entropy :

Answer 3

Is the entropy per mole of a substance under standard conditions unusually 298k at 100kpa

Question 4

What are sudden spikes in an entropy graph called

Answer 4

Phase transition

Question 5

What are the three factors that effect disorder in a system :

Answer 5

Moles

The physical state

Complexity

Question 6

What is the equation for delta system

Answer 6

∑system = ∑S products - ∑reactants

Question 7

How does temperature effect entropy

Answer 7

At a higher temperature the particles have a much greater range of energy’s . Therefore there are more possible energy levels that the molecules could possess , hence they have a higher entropy.

Question 8

Give the equation for delta surroundings

Answer 8

Delta surr = - (delta H/ T(kelvin))

Question 9

What is the 2nd law of thermodynamics

Answer 9

Every natural thermodynamics process proceeds in the direction in which the total entropy is increased

Question 10

What does it mean if delta S total is greater then 0

Answer 10

The reaction is spontaneous

Question 11

Give the equation for delta S total

Answer 11

Delta S total = delta Ssys + delta Ssurr

Question 12

At eqm there is no overall change this mean that delta S total equals

Answer 12

0

This is because there is no change in entropy in the system

Question 13

Info card :

Answer 13

If entropy does not change : therefore delta S total = 0

0 = delta S surr + delta Ssys

0= delta S surr + - (delta H/T)

Delta S surr = - ( delta +/- H / T )

Question 14

If a reaction cannot occurs however has a positive delta S total
What is it and what is its definition

Answer 14

Activation energy - the minimal energy for the reaction to occurs

Question 15

Endothermic reactions can be spontaneous and exothermic reactions are often not spontaneous, there are three main reasons for this

Answer 15

1) delta H tells us nothing about the kinetic inertness of the reactants
—> this is when energy must be put in in order to over come the activation energy

2) delta H quoted for standard conditions but are rarely performed under standard conditions

3) entropy changes and weather delta S total is negative or positive

Question 16

What is the equation for delta G

Answer 16

Delta G = delta H - T x delta S

Delta s being entropy change

Question 17

What does it mean if delta G is below zero

Answer 17

The reaction is readable