Reaction Mechanism, Intermediates, and Catalysts

Which of the following is a rate law, where the units of rate are equal to the units of the rate constant?

• Rate = k [A]0

• Rate = k [A]

• Rate = k [A] [B]

• Rate = k [A] [B] [C]0

Tags

NGSS.HS-PS1-5

Which answer choice correctly matches the integrated rate law shown below?

1/[A]_t = k t + 1/[A]₀

• A zero order reaction where a plot of 1/[A]t (y-axis) versus t (x-axis) will yield a straight line with slope = k

• A first order reaction where a plot of 1/[A]_t (y-axis) versus t (x-axis) will yield a straight line with slope = k

• A first order reaction where a plot of 1/[A]_t (y-axis) versus t (x-axis) will yield a straight line with slope = -k

• A second order reaction where a plot of 1/[A]_t (y-axis) versus t (x-axis) will yield a straight line with slope = k

A proposed mechanism for a given chemical reaction is given below.

STEP 1 (fast) A + B → J

STEP 2 (slow) J + A → C + F

STEP 3 (fast) F + A → C + D

Which combination of statements is consistent with the data above?

• Rate = k [A]² [B] and the overall reaction is 3A + B → 2C + D

• Rate = k [A] [B] and the overall reaction is 3A + B → 2C + D

• Rate = k [A]² [B] and the overall reaction is 3A + B → 2C + D + F + J

• Rate = k [A]³ [B] and the overall reaction is 3A + B → 2C + D

Tags

NGSS.HS-PS1-5

STEP 1 H₂O₂ + I^- → H₂O + OI^-

STEP 2 H₂O₂ + OI^- → H₂O + O₂ + I^-

Which species is the catalyst in the reaction?

• H2O2

• I-

• H2O

• OI-

STEP 1 H₂O₂ + I^- → H₂O + OI^-

STEP 2 H₂O₂ + OI^- → H₂O + O₂ + I^-

Which species is an intermediate?

• H2O2

• I-

• H2O

• OI-

Which chemical equation consistent with the mechanism provided?

STEP 1 H₂O₂ + I^- → H₂O + OI^-

STEP 2 H₂O₂ + OI^- → H₂O + O₂ + I^-

• 2H2O2 → 2H2O + O2

• 2H2O2 + I- → 2H2O + O2

• ½H2O2 + I- → H2O + O2

• ½H2O2 + I- → H2O + OI- + O2

Tags

NGSS.HS-PS1-2

A reaction of the reactants A and B, to produce products X and Y, can be summarized as;

3A + 2B → 2X + Y

What is the rate law for the reaction?

• Rate = k [A] [B]²

• Rate = k [A]² [B]²

• Rate = k [B]

• Rate = k [B]²

Tags

NGSS.HS-PS1-5

A reaction of the reactants A and B, to produce products X and Y, can be summarized as;

3A + 2B → 2X + Y

What is the value of the rate constant (with correct units)?

• 2 x 10-3M-1sec-1

• 2 x 10^-3M^-2sec^-1

• 8 x 10-3M-1sec-1

• 1 x 10^-3M^-2sec^-1

Tags

NGSS.HS-PS1-5

A reaction of the reactants A and B, to produce products X and Y, can be summarized as;

3A + 2B → 2X + Y

In experiment 3, what would be the rate of change of concentration of B measured in M sec^-1?

• Increase at 8 x 10^-3

• Increase at 2 x 10^-3

• Decrease at 8 x 10^-3

• Decrease at 2 x 10^-3

Tags

NGSS.HS-PS1-5

A reaction of the reactants A and B, to produce products X and Y, can be summarized as;

3A + 2B → 2X + Y

If Z is an intermediate, which of the following is a possible slow step in the mechanism?

• 2B → Z

• B → Z

• Z → 2B

Tags

NGSS.HS-PS1-5