stuff

Question 1

convert from an extensive (V) to an intensive (v)

Answer 1

v = V/m

Question 2

what is the difference between adiabatic and diathermic? How does this apply to the first law?

Answer 2

adiabatic = no heat transfer (delta U = W)
Diathermic = heat transfer

Question 3

Derive expression work done? what can you say if the reaction is reversible?

Answer 3

consider small change (w = Force x distance)
integrate
sub in force = pressure x area
therefore W = -integral (pext dv)
if reversible p ext = p

Question 4

What is the first law

Answer 4

delta U = q + w (work = - if work done by system)

Question 5

Learn triple/critical point diagram and saturation dome diagram

Answer 5

LEARN

Question 6

Expression for enthalpy

Answer 6

H = U + PV

Question 7

What can you say at constant volume?

Answer 7

delta U = q

Question 8

What can you say at constant pressure?

Answer 8

delta H = q
delta H = U + PV)
             = (q - W) + PV
             = q - PV + PV
             = q

Question 9

Relation between constant volume/pressure heat capacity?

Answer 9

Liquid/solid –> cp = cv

Ideal Gas –> cp = cv + R

Question 10

Isothermal reversible expansion of an ideal gas?

Answer 10

sub in pv = nRt into work expression

Question 11

How do you derive an expression for entropy change?

Answer 11

delta S = nRln(V2/V1) and q rev = nRtln(v2/V1)

divide by T –> therefore, delta S = qrev/T

Question 12

When does a reaction become spontaneous and irreversible?

Answer 12

delta S > 0

Question 13

Explain the Carnot cycle and draw diagram?

Answer 13

fun

Question 14

constant pressure phase transition?

Answer 14

q = delta H, therefore delta S = delta H/T

Question 15

Entropy change of an ideal gas?

Answer 15

delta U = q + w, delta S = qrev/T, constant volume heat capacity

Question 16

Clausius statement for the 2nd law?

Answer 16

All spontaneous processes are irreversible (eg heat flow from hot to cold spontaneously and irreversibly)

Question 17

What is the critical point?

Answer 17

the point at which phase boundaries disappear and a liquid and vapour cannot coexist in equilibrium

Question 18

What is the triple point?

Answer 18

The temperature and pressure where a liquid, solid and vapour can coexist in equilibrium

Question 19

What is Henrys Law?

Answer 19

amount of dissolved gas is proportional to its partial pressure in the gas phase

Question 20

What do you have to assume for Raoults Law?

Answer 20

ideal solution (structurally similar)

Question 21

Ideal gas law question

Answer 21

low pressure. might be better to use equation of state taking into account the fact that it isnt an ideal gas. This is because the intermolecular forces at high pressure would be significant

Question 22

What is the first law in words?

Answer 22

Energy cannot be created or destroyed

Question 23

how are work and energy equivalent?

Answer 23

weight falling over a pulley turning a propeller in water

Question 24

what is enthalpy?

Answer 24

the energy associated with a fluid entering or leaving a sysem