Reaction Rate

2H+ + O-2 →→→→ H2O

4K+ + C4- →→→→ K4C

H2O →→→→ 2H+ + O-2

4Cs+ + Pb4-Cs4Pb →→→→

2Al3+ + 3Ag2S →→→→

Al2S3 + 6Ag2+

2Al 3+ + 3Ra2S →→→→

Al2S3 + 6Ra 2+

HCl + NaOH→→→→ NaCl + H2O

3BaCl2 + 2H3PO4 →→→→

Ba3(PO4)2 + 6HCl

C3H8 + 5O2→→→→ 3CO2 + 4H2O

C6H12O6 + 6O2 →→→→

6CO2 + 6H2O

CuO + H2 →→→→ Cu + H2O

Rate Law

The mathematical

relationship between the rate

of a chemical reaction at a

given temperature and the

concentration of reactants.

moles/L =M

Molarity

Reaction Rate

The change in concentration of a reactant or product per unit time, generally calculated and expressed in moles per liter per second. (mol/sL) or

(M/s)

Average rate = ∆quantity/∆t

CO + NO2 → CO2 + NO

NO at t1 = 0.000 M and 0.00s

NO at t2 = 0.010 M and 2.00s

[0.010M – 0.000M] ÷ [2.00s –

0.00s] = 0.0050 M/s

CO + NO2 → CO2 + NO

CO2 at t1 = 0.000 M and 0.00s

CO2 at t2 = 0.030 M and 4.00s

[0.030M – 0.000M] ÷ [4.00s –

0.00s] = 0.0075 M/s

Factors which influence

reaction rate• Concentration

• Surface Area

• Temperature

• Catalyst

• Inhibitor

Catalyst

A substance that increases

the rate of a chemical

reaction by lowering

activation energies but is not

itself consumed in the

reaction.

Heterogeneous Catalyst

A catalyst that exists in

a different physical

state than the reaction

it catalyzes.

Homogeneous

Catalyst

A catalyst that exists in

the same physical

state as the reaction it

catalyzes.

InhibitorA substance that

slows down the

reaction rate of a

chemical reaction or

prevents a reaction

from happening.

Specific Rate Constant

A numerical value that

relates reaction rate

and concentration of

reactant at a specific

temperature.

Rate = k[A]

Reaction Order

For a reactant, describes how the rate is affected by the

concentration of that reactant.

Rate=k[A]m[B]n

aA +bB → products

Method of Initial Rates

Determines the reaction

order by comparing the initial

rates of a reaction carried

out with varying reactant

concentrations.

2NO + 2H2 → N2 + 2H2O

16.0 X 10-30.2000.2003

4.00 X 10-30.1000.2002

2.00 X 10-30.1000.1001

Initial Rate (M/s)Initial [B] (M)Initial [A] (M)Trial

aA + bB → products

Experimental Initial Rates for

2NO + 2H2 → N2 + 2H2O

According to the table, from

trial 1 to trial 2, as [A] doubles,

so did the final. This causes

the order to become 1.

According to the table, from

trial 2 to trial 3, as [B]

doubles, the final increased

by a multiple of four. This

causes the order to become

2.

2NO + 2H2 → N2 + 2H2O

Rate = k[A]1[B]2

Rate = k[NO]1[H2]2

4.0 X 10-30.2000.2003

2.00 X 10-30.1000.2002

2.00 X 10-30.1000.1001

Initial Rate (M/s)Initial [B] (M)Initial [A] (M)Trial

aA + bB→ products

Experimental Initial Rates for

According to the table,

from trial 1 to trial 2, as [A]

doubled, the final did not

change. This gave an

order of 0.

According to the table,

from trial 2 to 3, as [B]

doubled, so did the final.

This gave an order of 1.

Rate = k[A]0[B]1

Rate = k[B]

2ClO2 + 2OH- → ClO3- +

ClO2- + H2O

13.80.1000.1003

27.60.2000.1002

6.90.2000.0501

Initial Rate (M/s)Initial [B] (M)Initial [A] (M)Trial

aA + bB→ products

Experimental Initial Rates for

2ClO2 + 2OH- → ClO3- +

ClO2- + H2O

According to the table, from

trial 1 to trial 2, as [A]

doubled, the final increased

by a multiple of four. This

gave an order of 2.

2ClO2 + 2OH- → ClO3- +

ClO2- + H2O

According to the table,

from trial 2 to 3, as [B]

halved, so did the

final. This gave an

order of 1.

Rate = k[A]2[B]1

Rate = k[ClO2]2[OH-]1

Instantaneous Rate

The rate of decomposition at a specific time, calculated

from the rate law, the specific rate constant, and the concentrations of all the

reactants.

You can find the

instantaneous rate by

multiplying k (which is

given to you) by the

concentration of each

reactant after you find

each reactant’s order.

2NO + 2H2 → N2 + 2H2O

k=1.0 X10-5 s-1

Rate = k[NO]1[H2]2

Rate = k[0.030M]1[0.04M]2

Rate=1.0X10-5s-1 (0.03M)

(0.04M)2

Rate=4.8X10-10 M/s

Complex Reaction

A chemical reaction

that consists of two or

more elementary

steps.

Reaction Mechanism

The complete sequence of

elementary steps that make up a complex

reaction.

Intermediate

A substance produced in one elementary step of a complex reaction and

consumed in a subsequent elementary step. It does not appear in the final equation.

Rate-determining Step

The slowest elementary step in a complex reaction;

limits the instantaneous rate of the overall reaction