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100

Rate=k[A]^2[B]^1

What is the order with respect to:

  • (a) Reactant A?

  • (b) Reactant B?

  • (c) Overall reaction?

(a) 2nd

(b) 1st

(c) 3rd

100

A+2B→C

The rate law is determined to be:

Rate=k[A]1[B]2

You are given:

  • [A]=0.200 M

  • [B]=0.100 M

  • k=0.500 M−2s−1

Rate = 

0.00100M/s


100

What causes this decrease in Activation energy

Catalyst

100

The following table shows the initial concentrations of reactants and the initial rate of reaction for a chemical reaction.

Experiment [A] (mol/L) [B] (mol/L) Rate 

1             0.1                0.2            0.05 

2            0.2                  0.2          0.10 

3            0.1                 0.4            0.20

Question: Determine the rate law for the reaction and calculate the rate constant k

Rate=12.5[A][B]2

100

How many steps

3

200

In a certain reaction, doubling [B] while keeping [A] constant causes the rate to increase by a factor of 4. What is the order of the reaction with respect to B?

Second order with respect to B

200

  • Initial [A] = 0.200 M

  • [A] after 40.0 seconds = 0.050 M

  • The reaction is first-order

Find the rate constant k.

k=ln(0.200/0.050)/40.0=ln(4)/40.0≈1.38640.0=0.0347s−1

 k=0.0347 s−1

200


what is k

k = -slope 

200

The following data shows the concentration of reactant A at different times during the reaction.

Time (s)           [A] (mol/L) 

0                       0.50 

10                     0.40

20                      0.30

30                       0.25

Question: Using the integrated rate law for a first-order reaction, calculate the rate constant kkk.

k is 0.0231 s⁻¹. 

200

In a reaction mechanism, the overall reaction is given as:

A+B→C+D

The reaction mechanism consists of the following elementary steps:

  1. A→E+F

  2. E+B→C+D

Identify the rate-determining step (RDS) of the reaction mechanism. What does this imply for the overall rate law of the reaction?

RDS: step 1

rat law is Rate=k[A] 

300




1st order

300

  • Initial [A] = 0.100 M

  • [A] after 30.0 seconds = 0.050 M

  • The reaction is second-order

Find the rate constant k.

k=1/30.0(1/0.050−1/0.100)=1/30.0(20−10)=10/30=0.333M−1s−1

Answer: k=0.333 M−1s−1

300

What theory does this represent

Collision Theory

300

For a first-order reaction, the following table shows the concentration of a reactant over time.

Time (s)               [A] (mol/L) 

0                        0.30 

50                      0.15

100                  0.075

Question: Calculate the half-life of the reaction.

Since the concentration of A halves every 50 seconds, the half-life for this reaction is 50 seconds.

300

Consider the following reaction mechanism for the decomposition of hydrogen peroxide (H2O2):

  1. H2O2⇌H2O+O2(slow)

  2. O2+H2O2→H2O+O2(fast)

Write the rate law for the overall reaction based on the above reaction mechanism.

Rate=k[H2O2]

400

Q2. Table Data (One Reactant)

Consider the following data for a reaction:

[A] (M)Initial Rate(M/s) 

0.100         0.025   

0.200         0.100

0.400          0.400

Determine the order of the reaction with respect to A.

Second order with respect to A

400

  • Initial [A] = 0.500 M

  • [A] after 25.0 seconds = 0.300 M

  • The reaction is zero-order

Find the rate constant k.

  • [A]=−kt+[A]0⇒k=[A]0-[A]/t=0.500−0.300/25.0=0.200/25.0=0.00800M/s

 k=0.00800 M/s

400

What is the half life

4 minuets 

400

For the reaction A+B→CA + B  the rate law is given as Rate=k[A]1[B]2, and the rate constant k=3.0 L2/mol2⋅s The following table shows the initial concentrations of A and B, but some rate values are missing.

Experiment    [A] (mol/L)   [B] (mol/L)  Rate 

1                   0.10            0.20              x

2                0.20               0.10            0.12 

3              0.30                 0.40              y

Question: Fill in the missing rate values for Experiments 1 and 3.

x = .012

y = .144

400

The following reaction mechanism is proposed for the reaction of chlorine gas (Cl2) and methane (CH4):

  1. Cl2→2Cl (fast)

  2. Cl+CH4→CH3+HCl(slow)

  3. CH3+Cl2→CH3Cl+Cl(fast)

Question:

  • Identify the intermediates in this mechanism.


    • Cl is an intermediate because it is produced in Step 1 and consumed in Step 2 and Step 3.

    • CH3 is an intermediate because it is produced in Step 2 and consumed in Step 3.

500

A reaction has this experimental data:

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

0.100    0.100             0.020 

0.100     0.200           0.040 

0.200     0.200             0.160

Determine:

  • (a) The order with respect to A

  • (b) The order with respect to B

  • (c) The overall order

  • (a) A is second order

  • (b) B is first order

  • (c) Overall order = 3

500

You’re told that the half-life of a first-order reaction is 10.0 seconds.
What is the rate constant k?

t1/2=0.693/k⇒k=0.693/t1/2=0.693/10.0=0.0693s−1

  k=0.0693 s−1

500

What does k = at half life

k = .17325

500

A student is investigating the rate of a chemical reaction and collects the following data for the concentration of a reactant A over time:

Time (s)                [A] (mol/L)

 0                        0.100

50                           0.071 

100                      0.050  

150                     0.035

200                        0.025

What is the order (use linear regression) 

1st order

500

Overall reaction:

2NO+O2→2NO2

Proposed mechanism:

  1. NO+O2⇌NO3(fast equilibrium)

  2. NO3+NO→2NO2 (slow)


What is the Rate Law


Rate=k[NO]2[O2]