Kinetics Quiz #1        Monitoring Reaction Rates               Answers

1. Consider the following Reaction:  HCl(aq)  +    NaOH(aq)      H2O(1)  +  NaCl (aq)  The rate of this reaction could be determined by monitoring the change of concentration of :

A.        H +

B.        Cl -

C.        Na +

D.        H2O

2. Consider the following reaction:  2Al (s)  +  6HCl (aq)     2AlCl 3(aq) +  3H 2(g)

A 0.040 mole piece of aluminum reacted completely in 20 s. The rate of formation of hydrogen gas is:

A.        0.0013 mol/s

B.        0.0020 mol/s

C.        0.0030 mol/s

D.        0.0060 mol/s

3. Consider the following reaction: Zn(s)  +  2HCl (aq)     ZnCl 2(aq)  +  H 2(g)

Solid zinc was added to 1.0 M HCl.  In 20.0 s. the temperature of the container increased by 0.05oC and 25.00 ml of H2 was produced. The rate of this reaction was:

A.        0.5oC

B.        1.0 M HCl/s

C.        1.25 ml H2/s

D.        0.050 mol HCl/s

4.  Consider the following reaction : N 2(g)  +  3H 2(g)    2NH 3(g)

If the rate of formulation of NH3 is 9.0 x 10–4 mol/s, then the rate of consumption of N2 is:

A.        4.5 x 10-4 mol/s

B.        6.0 x 10-4 mol/s

C.        9.0 x 10-4 mol/s

D.        1.4 x 10-3 mol/s

5. In general, the reaction rates double when the temperature is increased by 10oC . The temperature of a reaction   is increased by 40oC. The rate of the reaction will be increased by:

A.        2

B.        4

C.        8

D.        16

6. Consider the following reaction: 2NO2(g)     2NO(g) +  O2(g)

Under certain conditions, the rate of decomposition of NO2 is 3.2 x 10-3 mol/s. The rate of the formation of O2 is:

A.        1.6 x 10-3 mol/s

B.        3.2 x 10-3 mol/s

C.        4.8 x 10-3 mol/s

D.        6.4 x 10-3 mol/s

7. An 8.00 g piece of magnesium was placed into 6.0 M HCl . After 25 s. 3.50 g of   unreacted magnesium remained. The average rate at which magnesium was consumed is:

A.        0.14 g/s

B.        0.18 g/s

C.        0.32 g/s

D.        4.50 g/s

8. The rate of a chemical reaction can be expressed in

A.        grams per mole.

B.        Energy consumed per mole.

C.        volume of gas per unit time.

D.        moles formed per liter of solution

9. Consider the following reaction at a constant temperature in an open system:

MgCO3(s)  +  2HCl(aq)     CO2(g)  + H2O(l)  + MgCl 2(aq)

Which of the following properties could be used to determine reaction rate?

A.        Mass of the system

B.        Pressure of the gas

C.        Concentration of H2O

D.        Concentration of MgCO3

10. At 30oC a 25.0 mL sample of bleach decomposes producing 50.0 mL of oxygen gas in 80 seconds. The rate of oxygen formation can be determined by the expression

A.        50.0 mL/80s

B.        50.0 mL/30oC

C.        25.0 mL/80s

D.        25.0 mL/30oC

11. A 25.0 mL sample of hydrogen peroxide decomposes producing 50.0 mL of oxygen gas in 137 s. The rate of formation of O2  in mL/min is

A.        0.182 mL/min

B.        0.365 mL/min

C.        10.9 mL/min

D.        21.9 mL/min

12.  Consider the following reaction:  2N2O5(g)     4 NO2(g)  +  02(g)

At a certain temperature the rate of decomposition of N2O5  is 2.5 x 10-6 mol/s. The rate of formation of NO2 is

A.        1.0 x 10-5 mol/s

B.        1.3 x 10-6 mol/s

C.        2.5 x 10-6 mol/s

D.        5.0 x 10-6 mol/s

13.       Consider the following reaction:

2CaCrO4(s)  +   2H+(aq)      ®    2Ca2+(aq)   +   H2O(l)       +        Cr2O72-(aq)

(orange)

The progress of  the reaction could be followed by observing the rate of

A.        mass loss

B.        decrease in pH

C.        precipitate formation

D.        formation of orange colour in the solution

14.       Which of the following could be used to monitor the rate of the reaction

A.               change in time

change in concentration

B.               change in mass

change in concentration

C.          change in concentration

change in time

D.           change in concentration

change in mass

15.       Consider the following reaction:

N2H4(l)   +  2H2O2(l)   ®    N2(g)  +  4H20(l)

In 1.0 seconds, 0.015 g of H2O2 is consumed. The rate of production of N2 is

A.        6.2  x  10-3 g/s

B.        7.5  x  10-3 g/s

C.        3.1  x  10-4 g/s

D.        1.5  x  10-2 g/s

16.       Which of the following could be used to measure the rate of the reaction?

A.        mL/s

B.        mL/g

C.        g/mL

D.        mL/mol

17.       Consider the following reaction in an open container:

MgCO3(s)   +   2HCl(aq)  ®  MgCl2(aq)  +  H2O(l)  +  CO2(g)

The rate of this reaction could be calculated by using which of the following?

A.        a change in Cl-

B.        an increase in [HCl]

C.        a change in pressure

D.        a decrease in mass of the system

18.       Consider the following reaction in an closed container:

MgCO3(s)   +   2HCl(aq)  ®  MgCl2(aq)  +  H2O(l)  +  CO2(g)

The rate of this reaction could be calculated by using which of the following?

A.        a change in Cl-

B.        an increase in [HCl]

C.        a change in pressure

D.        a decrease in mass of the system

19.       Consider the following reaction in an open beaker:

MgCO3(s)   +   2HCl(aq)  ®  MgCl2(aq)  +  H2O(l)  +  CO2(g)

The rate of this reaction could be calculated by using which of the following?

A.        an increase in MgCO3 mass

B.        a decrease in [MgCO3]

C.        an increase in [H2O]

D.        mass of the system over time

20.       Consider the following reaction:

MgCO3(s)   +   2HCl(aq)  ®  MgCl2(aq)  +  H2O(l)  +  CO2(g)

If the rate of consumption of HCl is 2.0 g/min what is the rate of formation of CO2?

A.        1.2 g/min

B.        2.4 g/min

C.        1.0 g/min

D.        2.0 g/min

21.       Which of the following could not be used to measure the rate of the reaction?

A.        s-1

B.        mL/s

C.        M/hour

D.        mol/L

22.       Consider the following reaction:

Fe2O3(s)  +  2Al(s)    ®   Al2O3(s)   +   2Fe(s)

If 0.50 mol of Fe is produced in 10.0 sec, what is the rate of consumption of Fe2O3 in mol/s?

A.        5.0  x  10-2 mol/s

B.        2.5  x  10-2 mol/s

C.        1.0  x  10-1 mol/s

D.        5.0 mol/s