Chapter 7

Question 1

what is the first law of thermodynamics?

Answer 1

the total energy of the universe is constant. Energy cannot be created or destroyed. Or the conservation of energy.

Question 2

non-spontaneous vs spontaneous?

Answer 2

non spontaneous processes require input to go. Spontaneous is on that occurs without on going outside intervention.

Question 3

thermodynamics?

Answer 3

study of spontaneity of a reaction

Question 4

a non spontaenous reaction is not ————-

Answer 4

impossible

Question 5

the 2 thermodynamic functions that determine the chemical potential of a system are …..

Answer 5

enthalpy and entropy

Question 6

enthalpy:

Answer 6

is a comparison of the bond energies of reactants to products in a chemical reaction

Question 7

so although most spontaneous reactions are exothermic, some spontaenous reactions are endothermic, what are some examples?

Answer 7

1. melting of ice above 0
2. vaporation of liquid water to haseous water
3. the dissolution of NaCl in water

Question 8

what is noticeable about the spontaenous reactions discussed in the previous cue cards….

1. melting of ice above 0
2. vaporation of liquid water to haseous water
3. the dissolution of NaCl in water

Answer 8

disorder or randomness increases

Question 9

if W increases in thr equation S= k ln W what increases?

Answer 9

entropy

Question 10

a system has greater entropy when….

Answer 10

1. ) it has more energetically equivalent ways to arrange the components of the system
2. ) the state with the highest entropy also has the greatest dispersal of energy
3. ) a state in which a given amount of energy is more highly dispersed has more entropy than a state in which the same energy is more highly concentrated

Question 11

second law of thermodynamics:

Answer 11

for any spontaneous process, the entropy of the universe increases.

Question 12

processes that decrease the entropy of the universe do not occur ————

Answer 12

spontaneously

Question 13

are enthalpy and entropy state functions?

Answer 13

yes

Question 14

S final:

Answer 14

entropy of state in which atoms are distributed between both flasks

Question 15

S initial:

Answer 15

entropy of state in which atoms are all in one flask

Question 16

the entropy of a sample of matter ——- as it changes state from a solid to a liquid or from a liquid to a gas.

Answer 16

increases

Question 17

if triangle Ssystem is negative then what is triangle Ssurroundings?

Answer 17

positive

Question 18

the freezing of water become nonspontaneous above 0 because….

Answer 18

the magnitude of the increase in the entropy of the surroundings due to the dispersal of energy into the surroundings is temperature dependent

Question 19

a process that emits heat into the surroundings (qsys negative) increases the entropy of the surroundings and results in what sign for triangle Ssurr?

Answer 19

poistive.

Question 20

a process that absorbs heat from the surroundings (qsys positive) decreases the entropy of the surroundings therefore resulting in what sign for triangle Ssurr

Answer 20

negative

Question 21

standard state for a gas:

Answer 21

pure gas at a pressure of exactly 1atm

Question 22

standard state for a liquid or solid?

Answer 22

at a pressure of 1 atm and at the temp of interest often 25 degrees C

Question 23

standard state for a substance in a solution?

Answer 23

concentration of exactly 1 M

Question 24

the absolute zero of entriopy is given by the third law of thermodynamics which states:

Answer 24

the entropy of a perfect crystal at absolute zero (0K) is zero. Therefore the absolute entropy of substances is always +

Question 25

the larger the molar masses the -------- the entropy

Answer 25

larger

Question 26

Factors that affect standard molar entropy:

Answer 26

1. the particular state of the substance g>l>s 2, a particular allotrope of the substance 3. molar mass of the substance 4. molecular complexity of the substance 5. extent or degree of dissolution

Question 27

when K<1

Answer 27

reaction is spontaneous in the revser direction

Question 28

whn K>1

Answer 28

reaction is spontaneous in forward dirction

Question 29

when K=1,

Answer 29

the reaction happens to be at equilibrium under standard conditions