2nd law of Thermodynamics and entropy

Question 1

2nd law of Thermodynamics

Answer 1

in isolated system, entropy can only increase

Question 2

change of entropy

Answer 2

proportional to heat transferred from system to surroundings

Question 3

change of entropy equation

Answer 3

DS>= Dq/T

Question 4

Dq

Answer 4

change of heat (s)

Question 5

T

Answer 5

temperature

Question 6

change in entropy at equilibrium

Answer 6

DS=Dq/T

Question 7

entropy equation depends inversely on temp

Answer 7

-DS=Dq/T

Question 8

equation of entropy change of surroundings

Answer 8

DS(surr) = Dq(surr)/T

or -DS=DH(surr)/T (DH=Dq at constant pressure)

Question 9

changes in exothermic reaction

Answer 9

entropy of system decreases

entropy of surroundings increases as energy is transferred out

Question 10

changes in endothermic reaction

Answer 10

entropy of system increases

entropy of surroundings decreases as energy if transferred in

Question 11

how to make a spontaneous reaction

Answer 11

total of entropy of system + surrounding must be >0

Question 12

equation for a spontaneous reaction

Answer 12

DS(total) = DS(system) + DS(surr) >0

Question 13

why does water freeze at -10 and not 10 degrees celsius

Answer 13

finding DS(surr) for each
temperature used in kelvin
DS(system) is -22Jk-1mol-1
find DS(total) and find which reaction occurs

Question 14

Gibbs free Energy (DG)

Answer 14

energy from reaction that is available to generate work

Question 15

equation for DG

Answer 15

DG = DH - TDS

Question 16

quantities of systems

Answer 16

macrostate and microstate

Question 17

macrostate system

Answer 17

temperature, pressure, volume

AKA collection of microstate

Question 18

microstate system

Answer 18

kinetic energy, force, velocity

Question 19

macrostate at equilibrium

Answer 19

does not change over time

microstates can be specified at anytime

Question 20

entropy in the concept of system

Answer 20

(S) no. microstates of system

Question 21

nr of microstates at given total energy

Answer 21

W(E)

Question 22

W entropy

Answer 22

omega

Question 23

Boltzmann contrast

Answer 23

Kb = 1.38064852*10 to power -23 m2kgS-2k-1

Question 24

entropy equation

Answer 24

S = Kb*In(W)

Question 25

consequences of increasing no. particles(N)

Answer 25

using binomial distribution

Question 26

equation of particles binomial distribution - P(N,NL)

Answer 26

N!/ (N-NL)!NL! *1/2N

Question 27

nature of equilibrium width in graph

Answer 27

width of distribution =total no. macrostates

gets narrower with around 1/sq root(N)

Question 28

increase in size of system

Answer 28

better defined equilibrium value

Question 29

example of 2 boxes and 4 particles on one side and when open how many will go to the other side
(labelling)

Answer 29

system - 2 boxes
macrostate - NL no.particles on left
microstate - W(4,NL) particular configuration of 4 particles in system

Question 30

example of 2 boxes and 4 particles on one side and when open how many will go to the other side (method)

Answer 30

• no. particles in NL (0,1,2,3,4)
• W(4,NL) - binomial distribution
• divide W(4,NL) by W(total)

Question 31

example of 2 boxes and 4 particles on one side and when open how many will go to the other side (total)

Answer 31

total microstate 16 - W(total)

able to be plotted on a graph( bar chart)