Chemical Kinetics

Question 1

study that deals with how fast the reaction will proceed to completion

Answer 1

chemical kinetics

Question 2

what is the formula for rate of reaction?

Answer 2

Rate = Δconc/Δt
or
Rate = Δ[A]/Δt

Δ = change; [ ] = conc. (in M usually); t = unit time; A = substance A

Question 3

in a rxn, what do u call something that is consumed?

Answer 3

reactant

Question 4

in a rxn, what is something that is formed?

Answer 4

product

Question 5

If 4A → 2B, what is the rate expression?

rate expression = rate of disappearance = rate of formation

Answer 5

Rate = -1/4 Δ[A]/Δt = 1/2 Δ[B]/Δt

Question 6

Accdg to the collision theory of reaction, atoms/molecules/ions must ____ for reactions to occur

Answer 6

collide

collision theory nga eh haha!

Question 7

↑ or ↓ rxn rate?

more collisions

Answer 7

↑ reaction rate

Question 8

in the transition state theory, what do you call the high energy intermediate that reactants must reach before falling into products?

Answer 8

transition state

Question 9

in the transition state theory, what do you call the energy that reactants must acquire to reach the transition state?

Answer 9

activation energy

Question 10

T or F

the rate of rxn is dependent on the reactants’ nature

Answer 10

True

same nature = ↑ rxn rate

Question 11

↑ or ↓ rxn rate?

reactants have fewer and weaker bonds

Answer 11

↑ rxn rate

Question 12

T or F?

reactions between molecules are slower than that of ions

Answer 12

True

mas mabilis ions kasi no bond-breaking is needed; can form bonds alr

Question 13

↑ or ↓ rxn rate?

compounds by ionic bonds

Answer 13

↑ rxn rate

Question 14

↑ or ↓ rxn rate?

the concentration of reactants is increased

Answer 14

↑ rxn rate

because collisions are more likely

Question 15

↑ or ↓ rxn rate?

in gases, the pressure in a container is higher than normal

Answer 15

↑ rxn rate

↑P↓V lower volume = more compressed = more collisions

Question 16

↑ or ↓ rxn rate?

in solids, the surface area is increased

Answer 16

↑ rxn rate

↑ surface area = breaking a solid reactant into smaller particles

breaking a solid reactant into smaller particles increases the number of particles available for collision

Question 17

↑ or ↓ rxn rate?

in solids, the surface area is increased

Answer 17

↑ rxn rate

↑ surface area = breaking a solid reactant into smaller particles

breaking a solid reactant into smaller particles increases the number of particles available for collision

Question 18

the average rate of a reaction ____ as the reaction proceeds

increases or decreases?

Answer 18

decreases

decreases kasi as the rxn proceeds, nababawasan conc. ng reactants

lower conc. of reactants leads to lower rxn rate

Question 19

enumerate the formula for rate law given the substance A

Answer 19

rate = k[A]^x

k = rate constant; x = rxn order; [ ] = conc.; A = reactant A

rate is directly proportional to the concentration of reactant

Question 20

what law expresses the relationship of the rate of rxn to the rate constant and the conc. of the reactants raised to its rxn order

Answer 20

rate law

Question 21

what do you call the reaction by which the rate does not vary with the increase or decrease in the concentration of the reactants?

Answer 21

zero-order reaction

rate of rxn is independent of all reactant concentrations

Question 22

what reaction can be defined as a chemical reaction for which the reaction rate is entirely dependent on the concentration of only one reactant?

if conc. is doubled, the rxn rate is also doubled

Answer 22

first-order reaction

Question 23

what reaction is one whose rate is proportional to the square of the concentration of one reactant? It also has a reaction rate that is proportional to the product of the concentrations of two reactants

if conc. is doubled, the rxn rate is quadrupled

Answer 23

second-order reaction

Question 24

in the case of multiple reaction steps, in what step will the rate depend?

slow step or fast step?

Answer 24

slow step; the rxn rate will always depend sa slow step

Question 25

in a rxn, what do you call something that is consumed first then produced later on as a final product? | first appears as a reactant then as a product

Answer 25

catalyst

Question 26

in a rxn, what do you call something that is produced first then is consumed later on? | first appears as a product then as a reactant

Answer 26

intermediate

Question 27

what do you call the time it takes for a conc. of a reactant to decrease by half of its original amount? | time it takes for half of the reactant to be converted to product

Answer 27

half-life

Question 28

half-life formula for zero-order reaction

Answer 28

t1/2 = [A]_i/2k

Question 29

half-life formula for first-order reaction

Answer 29

t1/2 = ln2/k

Question 30

half-life formula for second-order reaction

Answer 30

1/k[A]_i

Question 31

# T or F? a half-life of a first-order reaction depends on initial concentration of a reactant

Answer 31

False; given the formula ln2/k, a first-order reaction does not depend on the initial conc. of a reactant | only first & second-order rxns are dependent on initial conc. (reactant)

Question 32

is half-life dependent on the rate constant for all reaction orders? | yes or no

Answer 32

yes; also, since rate constant k is found on the denominator of every formula for half-life, **↑K ↓t1/2**

Question 33

rate constant k is dependent on where?

Answer 33

activation energy and temperature

Question 34

Integrated Rate Law formula for 0-order rxns

Answer 34

[A]_f = -kt + [A]_i | notice: k is negative, therefore slope is negative **(➘)**

Question 35

Integrated Rate Law formula for 1st-order rxns

Answer 35

ln[A]_f = -kt + ln[A]_i | notice: k is negative, therefore slope is negative **(➘)**

Question 36

Integrated Rate Law formula for 2nd-order rxns

Answer 36

1/[A]_f = kt + 1/[A]_i | notice: k is positive, therefore slope is positive **(➚)**

Question 37

# ↑ or ↓ rxn rate? increase in temp

Answer 37

↑ rxn rate? | ↑temp = ↑kinetic energy = ↑collision = ↑rxn rate

Question 38

enumerate arrhenius equation | (be familiar lang daw but no solving regarding this (hopefully))

Answer 38

ln(k) = -Ea/RT + ln(A) or k = Ae^-Ea/RT wherein: k = rate constant, A = collision frequency, -Ea = activation energy, R = gas constant (8.314 kJ/mol), T = abs temp, e = euler's number

Question 39

what do you call the species not directly involved in a rxn, but speeds it up?

Answer 39

catalyst

Question 40

what increases the rate by lowering activation energy of the rxn by providing alternative pathways for the rxn?

Answer 40

catalyst

Question 41

there are 3 types of catalysts, what are they?

Answer 41

1. heterogenous 2. homogenous 3. enzyme

Question 42

type of catalyst wherein the catalyst and reactants are of different phases

Answer 42

heterogenous catalyst

Question 43

type of catalyst wherein catalysts and reactants are of the same phase | faster since they r in the same phase

Answer 43

homogenous catalyst

Question 44

this type of catalyst involves enzymes that have active sites that specifically bind to substrates

Answer 44

enzyme