Exam 2

Question 1

what is the driving force behind a spontaneous reaction?

Answer 1

motional freedom of particles increasing

Question 2

during a spontaneous chemical reaction, it is found that the change in Ssys is less than 0. what does this mean?

Answer 2

the change in Ssurr is greater than 0 and its magnitude is greater than the change in Ssys

Question 3

when is a process always spontaneous?

Answer 3

change in H<0 and change in S>0

Question 4

second law of thermodynamics

Answer 4

the entropy of a universe increases in any spontaneous reaction

Question 5

third law of thermodynamics

Answer 5

entropy of a perfect crystal at absolute zero is 0 while W=1
provides a baseline/refrence for entropy

Question 6

microstates

Answer 6

unique distribution of particles among energy levels

Question 7

how does entropy affect spontaneity?

Answer 7

S<0 less spontaneous

more spread out means its more spontaneous

Question 8

what factors affect reaction rates?

Answer 8

• physical state of reactant
• concentration of reactants
• temperature
• presence of a catalyst

Question 9

enthalpy

Answer 9

change in heat

Question 10

three types of motion

Answer 10

translational, vibrational, rotational

Question 11

how does temperature influence spontaneity?

Answer 11

higher temperature means increase in collisions, therefore higher spontaneity

Question 12

integrated rate law

Answer 12

change in concentration of a reactant with time

Question 13

units for 0th order

Answer 13

M/s

Question 14

units for 1st order

Answer 14

1/s

Question 15

units 2nd order

Answer 15

1/Ms

Question 16

activation energy

Answer 16

minimum energy needed to break bonds in reactants and form bonds in the products

Question 17

transition state/activation complex

Answer 17

high energy transition state

peak

Question 18

reaction mechanisms

Answer 18

set of steps that describe how a reaction occurs at the molecular level

Question 19

rate-determining step

Answer 19

slowest step in the reaction

Question 20

homogeneous catalyst

Answer 20

catalyst in the same phase as the reactants

Question 21

heterogeneous catalyst

Answer 21

catalyst in a different phase from the reactants

Question 22

catalysts

Answer 22

not consumed, speeds up reaction, lowers activation energy

Question 23

what must happen for a reaction to occur?

Answer 23

1. molecules must collide
2. must exceed the threshold energy
3. must collide with proper orientation

Question 24

how does a lower energy affect a spontaneous reaction?

Answer 24

makes it more stable

Question 25

what is energy distribution affected by?

Answer 25

molecular motion and volume

Question 26

energy state/level

Answer 26

allowed value of energy

Question 27

w

Answer 27

number of microstates

Question 28

is motion a type of kinetic energy?

Answer 28

yea

Question 29

what increases with temperature?

Answer 29

motion

Question 30

how do exothermic reactions affect their surroundings?

Answer 30

have the possibility to increase the entropy of their surroundings

Question 31

what is the energy change of a reversible process?

Answer 31

no net flow of energy between the system and the surroundings

Question 32

what does the entropy change experienced by the surroundings of a chemical thermodynamic system depend on?

Answer 32

whether the process is exothermic or endothermic

Question 33

what remains constant with Gibbs free energy?

Answer 33

temp and pressure

Question 34

if something is spontaneous what is the change in G of the system equal to?

Answer 34

less than 0

Question 35

what does a reaction rate depend on?

Answer 35

concentration

Question 36

what happens to the reaction rate as the concentration decreases?

Answer 36

the reaction rate decreases

Question 37

how are exponents in a rate law determined?

Answer 37

experimentation only

Question 38

does the rate constant depend on the concentration of the reactants?

Answer 38

nah

Question 39

what controls the reaction rate in a pseudo-first-order reaction?

Answer 39

concentration of the limiting reactant

Question 40

pseudo-first-order

Answer 40

all reactants but one are present at such high concentrations that they don't decrease significantly during the reaction

Question 41

zero order

Answer 41

rate of reaction is independent of concentration

Question 42

3rd order units

Answer 42

1/M2s

Question 43

rate law for 0 order

Answer 43

rate=k

Question 44

which order has 1/something

Answer 44

second order

Question 45

how does a larger value of W affect entropy?

Answer 45

more entropy!!