Kinetics

Question 1

What is the reaction rate?

Answer 1

The speed of a chemical reaction, used to measure how fast the reaction make products or uses reactants

Question 2

What is rate?

Answer 2

How much a quantity changes in a given period of time

Question 3

What is the average rate?

Answer 3

The change in measured concentrations over any particular time period

Question 4

What is the instantaneous rate?

Answer 4

The change in [] over one specific time period

Question 5

What are three common techniques used to monitor a reaction mixture?

Answer 5

Polarimetry, spectroscopy, and pressure measurement

Question 6

What is rate law?

Answer 6

An equation relating concentration of reactants to rate when the reverse reaction is negligible

Question 7

What is the order of the reaction?

Answer 7

The sum of the exponents on the reactants

Question 8

If a reaction is zero order…

Answer 8

Doubling [a] will have no effect on the reaction rate

Question 9

If a reaction is 1st order…

Answer 9

Doubling [a] will double the rate of the reaction, therefore it is directly proportional to the reactant [].

Question 10

If a reaction is 2nd order…

Answer 10

Doubling [a] will quadruple the rate of the reaction because rate is directly proportional to the square of the reactant concentration

Question 11

For a particular reaction in which A → products, a doubling of the concentration of A causes the reaction rate to double. What is the order of the reaction?

Answer 11

1st order

Question 12

For a reaction

rate = k[A]^m[B]ⁿ

what will the overall order be?

Answer 12

m+n

Question 13

What are the units referring to each one of the reaction orders?

Answer 13

zero order = M/s

first order = 1/s or s^-1

second order = 1/M.s or M^-1s^-1

Question 14

In a forward reaction the concentration of the reactants is ___________ and of the products is ____________

Answer 14

Decreasing, increasing

Question 15

In a graph of [] over time, the rate can be determined if ___________ by applying the ____________ of ___.

Answer 15

The [] of a substance is known at two distinct points in the reaction, by applying the slope formula of delta y/delta x.

Question 16

The average rate is the more time specific one.

Answer 16

False, it is the instantaneous rate.

Question 17

Reaction rate can be determined by the balanced reaction alone.

Answer 17

False, it cannot be determined by the balanced chemical equation alone.

Question 18

What is the rate formula of a reaction?

Answer 18

Rate = k[A]^m[B]ⁿ

Question 19

Which formula can be used to solve for the constant “k”?

Answer 19

k = rate/[A]^m

Question 20

What is the integrated rate law?

Answer 20

It’s what identifies the relationship of the [] reactants vs time

Question 21

What is the half-life of a reaction?

Answer 21

It is the time required for the concentration of a reactant to fall to 1/2 of its initial value.

Question 22

What if the reaction mechanism?

Answer 22

A series of individual chemical steps by which an overall chemical reaction occurs.

Question 23

At the beginning of the reaction, the [] of the product is always:

Answer 23

Zero

Question 24

The rate of a a chemical reaction speeds up as the reactants form products.

Answer 24

False, it slows down

Question 25

The rate law is determine by the coefficients of the balanced equation

Answer 25

False

Question 26

If the units of "k" were M/s, we are able to determine that the reaction is:

Answer 26

Zero order

Question 27

If the units of "k" were 1/M s, we would be able to determine that the reaction is:

Answer 27

Second order

Question 28

If we collect concentration and rate data that shows the rate remains the same with concentration changes, we can determine that the reaction is:

Answer 28

Zero order

Question 29

How do you selected which integrated rate law equation to use?

Answer 29

It is based upon the reaction order

Question 30

What is the general concept of Kinetics?

Answer 30

rate = -Δ[reactant]/ΔT = Δ[product]/ΔT

Question 31

For a particular reaction in which A → products, a doubling of the concentration of A causes the reaction rate to double. What is the order of the reaction?

Answer 31

1st order

Question 32

What does the slope (or curve) indicate in an integrated rate law graph?

Answer 32

The rate order

Question 33

How can we define dynamic equilibrium?

Answer 33

The rates of the forward and reverse reactions are equal and opposite

Question 34

Once equilibrium is stablished, the [] of the reactant and products double.

Answer 34

False, once they reach equilibrium the [] does not change

Question 35

What does it mean if **K** \>\> 1?

Answer 35

That the reaction favors product formation at equilibrium

Question 36

What does it mean if **K** \<\< 1

Answer 36

That the reaction favors reactant formation at equilibrium

Question 37

What does it mean if **K =** 1?

Answer 37

That the neither product is favored at equilibrium and reaction proceeds to midway point

Question 38

What is the term for when rates of the forward and reverse reactions occur at the same rate?

Answer 38

Dynamic equilibrium

Question 39

K is not the result of the concentrations of the reactants and the products.

Answer 39

False, K is the result of the concentrations of the reactants and the products.

Question 40

The _________ of a reaction is the time required for the concentration of a reactant to fall to 1/2 of its initial value

Answer 40

Half-life

Question 41

What is the series of individual chemical steps by which an overall chemical reaction occurs?

Answer 41

Reaction Mechanism

Question 42

What is an elementary step?

Answer 42

A step that cannot be broken down into simpler steps

Question 43

What are the two requirements for a reaction mechanism?

Answer 43

The steps must sum to the overall reaction and the mechanism must predict an experimentally observed rate law

Question 44

What are molecules that can be canceled in a reaction mechanism?

Answer 44

Reaction intermeadiates (similar to spectator ions)

Question 45

The rate determining step is much faster than the others.

Answer 45

False, it is much slower than the others

Question 46

What is the reactio quotient (Qc)?

Answer 46

The ratio at any point in the reaction of the [] of the products raised to their stoichiometric coefficients divided by the [] of the reactants raised to their stoichiometric coefficients.

Question 47

What happens if Q \< K?

Answer 47

The reaction goes to the right, towards the products

Question 48

What happens if Q\> K?

Answer 48

The reaction goes to the left, towards the reactants

Question 49

What happens if Q = K?

Answer 49

The reaction is at equilibrium

Question 50

If your reaction reads: 2CO(g) CO₂(g) + C(s) What will your equilibrium equation be?

Answer 50

K = [CO₂]/[CO]² Because solids are not included in this type of reaction

Question 51

If your reaction reads: CO₂ (g) + H₂O (l) H⁺(aq) + HCO₃^-(aq) What will the equilibrium constant be?

Answer 51

K = [H⁺][HCO₃^-]/[CO₂]

Question 52

This is straight forward. What types of substances would not be included in writing an equilibrium constant expression?

Answer 52

Solids and liquids

Question 53

When the reaction is reversed, the new K is the _____ of the original.

Answer 53

Inverse

Question 54

When the reaction is mulitiplied by a factor, the new K is the "original K" rasied to the power of the factor.

Answer 54

true

Question 55

When is it more likely for the *x is small rule* to be applied?

Answer 55

The *x is small* approximation is most likely to apply to a reaction with a small equilibrium constant and an initial concentration of reactant that is not too small

Question 56

Kc's unit is grams

Answer 56

False, Kc is unitless but based upon concentration, is is measured in M