Chapter 13 Test

For the reaction X + Y ---> Z, the reaction rate is found to depend only upon the concentration of X. A plot of 1/X verses time gives a straight line.
What is the rate law for this reaction?

For a second order reaction, the half-life is equal to

For the hypothetical reaction A + 3B ---> 2C, the rate of appearance of C given by ([C]/t) may also be expressed as

A certain first-order reaction A ---> B is 25% complete in 42 min at 25C. What is the half-life of the reaction?

In general, to calculate the activation energy for an elementary step given the rate constants at two different temperatures, which equation should be used?

In general, to calculate the rate constant for a first order decomposition reaction, A----> products, given the time needed to decrease the initial concentration by one half, which equation should be used?

Which one of the following changes would alter the rate constant (k) for the reaction 2A + B ----> products?

Nitric oxide reacts with chlorine to form nitrosyl chloride, NOCl. Use the following data to determine the rate equation for the reaction.
NO + 1/2Cl2 ----> NOCl

For the chemical reaction system described by the diagram below, which statement is true?
If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is –95 kJ/mol, what is Ea for the reverse reaction?

A certain reaction A  products is second order with respect to A with a rate constant, k, 0.122 M-1min-1. Starting with [A]o = 1.01M, how many seconds will it take for A to reach a concentration of 0.750M?

Which one of the following changes would alter the rate constant (k) for the reaction 2A + B ----> products?

For the reaction A + 3B ----> 2C, the rate of disappearance of B given by ([B]/t) may also be expressed as

A certain first-order reaction A ----> B is 25% complete in 42 min at 25C. What is the half-life of the reaction?

The reaction A + 2B ----> products has been found to have the rate law, rate = k[A] [B]2. While holding the concentration of A constant, the concentration of B is increased from x to 3x. Predict by what factor the rate of reaction increases.

Concerning the rate law, Rate = k[A][B], what are appropriate units for the rate constant k?

The following mechanism has been suggested for the reaction:
H2O2 +2H+2I----> I2+2H2O
H2O2 +I ---->HOI +OH
OH + H ----> H2O
HOI+H+I----> I2+H2O


Identify the rate law that is consistent with this mechanism.

For a second order reaction, the half-life is equal to

A reaction was experimentally determined to follow the rate law, Rate = k[A]2 where k = 0.456 s-1M-1. Starting with [A]o = 0.500 M, how many seconds will it take for [A]t = 0.250 M?

Nitric oxide gas (NO) reacts with chlorine gas according to the chemical equation given below.
NO + ½Cl2 ----> NOCl
The following initial rates of reaction have been measured for the given reagent concentrations.
Which of the following is the rate law (rate equation) for this reaction?

Concerning the rate law, Rate = k[A]0, what are appropriate units for the rate constant k?

Concerning the rate law, Rate = k[A]2[B], what are appropriate units for the rate constant k?

For the chemical reaction system described by the diagram below, which statement is true?

Use the table of data shown below to calculate the average rate of the reaction A----> B between 10 s and 20 s.

time (s) [A] mol/L
0 0.20
5 0.14
10 0.10
15 0.071
20 0.050

For the reaction BrO3– + 5Br–+ 6H+  3Br2 + 3H2O at a particular time, –[BrO3–]/t = 1.5  10–2 M/s. What is –[Br–]/t at the same instant?

In general, to calculate the rate constant for a second order reaction with respect to A, given an initial and final concentration as well as the time required for this change, which equation should be used?