Reaction Rates, Collision Theory

Chemistry 12 Quiz I - 1 Unit I.1 – I.6 Reaction Rates, Collision Theory

1. Which of the following could not be units for reaction rate? A. sec-1 B. g/mL C. M/min D. ºC/hour

2. Which of the following would not be units for reaction rate? A. g/s B. M/min C. kJ/mol D. kPa/min

3. Which factor affects the reaction rate of heterogeneous reactions, but not of homogeneous reactions? A. catalyst B. temperature C. surface area D. concentration

4. Which of the following would have the highest reaction rate at room temperature? A. H2(g) + I2(g) → 2HI(g) B. H2S(g) + Cl2(aq) → 2HCl(aq) + S(s) 2+ 2- C. Ca (aq) + C2O4 (aq) → CaC2O4(s) D. Mg(s) + 2H2O(l) → Mg(OH)2(aq)+ H2(g)

5. Consider the reaction:

H2(g) + I2(g) → 2HI(g) Which of the following would decrease the rate of reaction? A. an increase in [I2] B. a decrease in [HI] C. a decrease in [H2] D. an increase in temperature 6. Consider the reaction:

ZnS(s) + H2SO4(aq) + ½O2(g) → ZnSO4(aq) + S(s) + H2O(l) What would increase the fraction of successful collisions?

I increasing temperature II increasing surface area of ZnS

III increasing [H2SO4] IV adding a suitable catalyst

A. I and II only B. I and IV only C. II and III only D. I, II, III and IV

7. Which of the following represents the typical mathematical relationship between reaction rate and time? D

8. Consider the reaction:

2Al(s) + 3CuCl2(aq) → 2AlCl3(aq) + 3Cu(s) What is the rate of Al consumption (in mol/min) if 0.98 g Cu are produced in 2.5 minutes? A. 4.1 x 10-3 B. 6.2 x 10-3 C. 9.3 x 10-3 D. 3.9 x 10-1 9. Consider the following reaction:

2Al(s) + 3CuCl2(aq) → 3Cu(s) + 2AlCl3(aq) If 0.56 g Cu is produced in 1.0 minute, what mass of Al is used up in 20.0 seconds ? A. 0.053 g B. 0.12 g C. 0.16 g D. 0.37 g

10. Consider the following reaction:

CH3COOH(aq) + NaHCO3(s) → NaCH3COO(aq) + CO2(g) + H2O(l) Which of the following properties could best be used to measure the reaction rate? A. the volume of CO2 B. the volume of H2O C. the mass of CH3COOH D. the surface area of NaHCO3

11. Consider the following experimental results:

Experiment 1 Experiment 2

Reactants powdered Cu and HCl chunk of Cu and HNO3 Temperature 20ºC 10ºC

Concentration of acid 0.6 M HCl 0.4 M HNO3 Rate low high

Which of the following factors would account for the lower rate in Experiment 1? A. temperature B. nature of reactants C. surface area of Cu D. concentration of acid

12. Consider the following reaction:

Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) In two different experiments, equal moles of Zn and equal volumes of HCl are reacted. After 2 minutes, the volume of H2 produced is recorded as follows:

Zn Temp [HCl] Volume H2 (mL) Experiment 1 strip 10ºC 10.0 M 10.6 Experiment 2 powdered 15ºC 3.0 M 7.3

Which of the following factors explains why the rates are different? A. [HCl] B. temperature C. nature of reactants D. surface area of Zn 13. Which of the following would have a positive value for ΔH?

I. the evaporation of water II. the burning of a match

III. the explosive reaction between H2 and O2 IV. a chemical cold pack

A. III only B. IV only C. I and IV D. II and III