# Worksheet: Rate Laws from Initial Rates

In this worksheet, we will practice using measurements of initial rate to deduce the rate law of a reaction and the order of reaction for each reactant.

Q1:

In a reaction between compounds and , doubling the concentration of increases the rate of reaction by a factor of 4. However, tripling the concentration of reactant increases the rate by a factor of 3.

What is the order of reaction with respect to ?

What is the order of reaction with respect to ?

Q2:

In a reaction between compounds and , quadrupling the concentration of doubles the rate of reaction. However, doubling the concentration of reactant increases the rate by a factor of 8.

What is the order of reaction with respect to ?

• A2
• B1
• C
• D4
• E

What is the order of reaction with respect to ?

Q3:

Hypochlorite and iodide ions react to form hypoiodite and chloride ions: The initial rate of reaction was measured at three different reactant concentrations, as shown in the table.

(M) (M) Initial Rate (M/s)

Determine the rate law for this reaction.

• ARate =
• BRate =
• CRate =
• DRate =
• ERate =

Determine the appropriate units for the rate constant of this reaction, .

• AL3/mol3⋅s
• Bs−1
• CM/s
• DL/mol⋅s
• EL2/mol2⋅s

Expressing concentrations in molars and time in seconds, estimate, to 3 significant figures, the numerical value of the rate constant, .

• A
• B
• C
• D
• E

Q4:

Nitric oxide reacts with chlorine to form nitrosyl chloride : The initial rate of reaction of nitric oxide was measured at three different reactant concentrations, as shown in the table.

(M) (M) Initial Rate (M/s)
0.100 0.100
0.100 0.150
0.150 0.100

Determine the rate law for this reaction.

• ARate =
• BRate =
• CRate =
• DRate =
• ERate =

Determine the appropriate unit for the rate constant of this reaction, .

• AL/mol⋅s
• BL3/mol3⋅s
• Cs−1
• DL2/mol2⋅s
• EM/s

Expressing concentrations in units of molars and times in units of seconds, estimate, to 3 significant figures, the numerical value of the rate constant, .

Q5:

 Time (s) [ A ] (M) 4 8 12 16 20 0.22 0.144 0.11 0.088 0.074

By plotting suitable functions of the tabulated data, determine the appropriate unit for the rate constant of this reaction.

• AL/mol⋅s
• BL3/mol3⋅s
• Cs−1
• DM/s
• EL2/mol2⋅s

Expressing concentrations in molars and time in seconds, estimate, to 3 significant figures, the numerical value of the rate constant for this reaction.