13A.5

Question 1

is S system effect by T

Answer 1

no, the effect is very little

Question 2

is S surroundings effected by T

Answer 2

yes it is

Question 3

if the S total is positive the reaction is

Answer 3

spontaneous

Question 4

what is the colour of N2O4

Answer 4

colourless

Question 5

what is the colour of 2 NO2

Answer 5

brown

Question 6

at hot temperature the volume of a mixture would

Answer 6

increase because the mixture expand

Question 7

at cold temperature the volume of a mixture would

Answer 7

decrease as the mixture would become smaller

Question 8

the entropy change for a mixture of any two gases in any proportion moving to the equilibrium constant is

Answer 8

is always positive so it will be always spontaneous both forward and backward

Question 9

what is graph that can show a reversible reaction that is spontaneous both ways

Answer 9

page 72

Question 10

can a spontaneous eq go to completion

Answer 10

no it cant go to completion as we can see on the graph that show a reversible reaction that is spontaneous both ways (PAGE 72) that from the eq mixture to either reactant or product the entropy is negative so it cant go to completion unless we interfere

Question 11

at eq the total entropy is

Answer 11

zero as S total (forward) = S total (backward)

Question 12

total entropy and Kc or Kp is linked by

Answer 12

S total = R In K ( R is the gas constant)

Question 13

does Kc/Kp increase with entorpy

Answer 13

yes and the proof S total = R ln K

Question 14

what happens when you put the mixture of N2O4 and 2NO2 (in eq) in hot water

Answer 14

the eq will shift to the right making the mixture darker brown (since its endo forward) and the volume with expand

Question 14

what happens when you put the mixture of N2O4 and 2NO2 (in eq) in cold water

Answer 14

the eq will shift to the right making the mixture light brown ( since its Exo backwards) and the volume to decrease

Question 15

if a reaction in eq has a positive eq forward and backward

Answer 15

that means that both reactions are spontaneous

Question 16

what is the expression for K using S total = R ln K

Answer 16

K = e^ S total / R (div on page 72)

Question 17

the thermodynamic value of Kc/Kp has

Answer 17

no units so when we calculate Kc/Kp using S total = R ln K K has no units

Question 17

how can we change the experimental value of Kc/Kp to the thermodynamic value

Answer 17

for Kc you need to dividing each concentration by 1 mol dm^-3

for Kp you need to divided each partial pressure by 1 atm

Question 18

large value of K the eq position is

Answer 18

more to the right

Question 19

smaller value of K the eq position is

Answer 19

more to the left