midterm

Question 1

factors affecting rxn rates (4)

Answer 1

1. physical state (homo/hetero)
2. []
3. temp
4. catalysis

Question 2

rate law

Answer 2

the relationship btwn the rate of the rxn and the [react]

Question 3

zero-order

Answer 3

one stays the same and the other doubles independently

Question 4

first order

Answer 4

rate directly proportional to [react]

Question 5

2nd order

Answer 5

proportional to the square

Question 6

overall rxn order

Answer 6

sum of all the orders of each reactant

Question 7

1st order slope

Answer 7

-k

Question 8

2nd order slope

Answer 8

k

Question 9

zero order slope

Answer 9

-k

Question 10

half life (t 1/2)

Answer 10

the time taken for 1/2 of a reactant to be consumed

Question 11

lifetime (2)

Answer 11

• the time taken for the rxn to decrease to 1/e

- a measure of the avg life expectancy of a chem identity

Question 12

Eact

Answer 12

the E barrier that needs to be overcome to make reactants into prods (J/mol)

Question 13

exponential factor

Answer 13

fraction of R that become P’s; those with enough E

Question 14

frequency factor

Answer 14

of molecs R that approach the barrier per unit of time (given)

Question 15

what happens to k as temp incs?

Answer 15

inc

Question 16

if k and rate dec, what happens to the Eact?

Answer 16

inc

Question 17

when does temp have a greater effect on rxns?

Answer 17

with ones w/ high Eact

Question 18

rxn mechanisms

Answer 18

a series of individual chem steps by which an overall chem rxn occurs

Question 19

what do intermediated and catalysts have in common in respect to a rxn mechanism

Answer 19

not found in the overall rxn

Question 20

Rate Determining Step

Answer 20

limits the overall rate of the rxn; the slowest one

Question 21

overall rxn

Answer 21

sum of the elementary steps

Question 22

steady state consumption

Answer 22

rate of formation of intermediate = rate of consumption of intermediate

Question 23

how can the rate of a step be determined

Answer 23

by using the balanced eqtn of that specific step

Question 24

intermediates

Answer 24

species that play a role in the rxn but do not appear in the overall balanced eqtn

Question 25

catalyst

Answer 25

substance that increases the rate of a chem rxn but that is not consumed by the rxn

Question 26

homogenous catalyst

Answer 26

catalyst in same phase as reacts

Question 27

heterogenous catalyst

Answer 27

catalyst in diff phase than reacts

Question 28

thermodynamics

Answer 28

the general study of E and its interconversions

Question 29

thermochemistry

Answer 29

the study of the relationship btwn chemistry and E

Question 30

work (w)

Answer 30

a force acting through a distance (J)

Question 31

heat (q)

Answer 31

the flow of E caused by a temp diff (J)

Question 32

kinetic E

Answer 32

E associated w/ motion (J)

Question 33

thermal E

Answer 33

E associated w/ temp (J)

Question 34

potential E

Answer 34

E associated w/ position or composition

Question 35

chemical E

Answer 35

a form of potential E associated w/ positions of electrons and nuclei in a system

Question 36

heat

Answer 36

the transfer of kinetic E from a hotter body to a cooler one (NEVER in reverse)

Question 37

heat in

Answer 37

endo

Question 38

heat out

Answer 38

exo

Question 39

temp (3)

Answer 39

- a measure of heat - describes how hot something is relative to a standard - a type of KE

Question 40

1st law of thermodynamics

Answer 40

E can neither be created nor destroyed, only transferred

Question 41

system

Answer 41

a specific area of interest

Question 42

surroundings

Answer 42

everything else

Question 43

internal E (U)

Answer 43

the sum of al the kinetic and potential energies of all the particles that make up the system

Question 44

the total E of the universe is constant, meaning that

Answer 44

the internal E lost by the sys is = to the internal E gained by the surroundings

Question 45

q is +

Answer 45

when heat is absorbed by the sys

Question 46

q is -

Answer 46

when heat is lost by the syst

Question 47

w is -

Answer 47

done by syst

Question 48

w is +

Answer 48

done on sys

Question 49

enthalpy (H)

Answer 49

the sum of its internal E and the products of its pressure and volume

Question 50

endo rxn feels

Answer 50

cold to the touch

Question 51

exo rxn feels

Answer 51

warm to the touch

Question 52

chem/potential E

Answer 52

the source of E given off in an exo rxn

Question 53

Hess's law

Answer 53

the change in enthalpy for a stepwise process is the sum of H changes of the steps