6. Chemical Kinetics

1.Which of the following is (are) important in determining whether a reaction occurs? I. Energy of the molecules II. Orientation of the molecules

2. Consider the reaction between solid CaCO3 and aqueous HCl. The reaction will be speeded up by an increase in which of the following conditions? I. Concentration of the HCl II. Size of the CaCO3 particles III.    Temperature

3. Excess magnesium was added to a beaker of aqueous hydrochloric acid on a balance. A graph of the mass of the beaker and contents was plotted against time (line 1). What change in the experiment could give line 2? I. The same mass of magnesium but in smaller pieces II. The same volume of a more concentrated solution of hydrochloric acid III.    A lower temperature  

4. The rate of a reaction between two gases increases when the temperature is increased and a catalyst is added. Which statements are both correct for the effect of these changes on the reaction?

5. Which of the following is (are) altered when a liquid at its boiling point is converted to a gas at the same temperature? I. The size of the molecules II. The distance between the molecules III.    The average kinetic energy of the molecules

6. Based on the definition for rate of reaction, which units are used for a rate?

7. Which of the quantities in the enthalpy level diagram below is (are) affected by the use of a catalyst? Time

8. In the Haber process for the synthesis of ammonia, what effects does the catalyst have?

9. Which statement is correct for a collision between reactant particles leading to a reaction?

10. Which change of condition will decrease the rate of the reaction between excess zinc granules and dilute hydrochloric acid?

11. The table shows the concentrations of reactants and products during this reaction. 2A + B → C + 2D The rate of reaction can be measured by reference to any reactant or product. Which rates are correct for this reaction? I. rate = –2 mol dm–3 min–1 for A II. rate = –1 mol dm–3 min–1 for B III.    rate = –1 mol dm–3 min–1 for C

12. In general, the rate of a reaction can be increased by all of the following except  

13. At 25°C, 100 cm3 of 1.0 mol dm–3 hydrochloric acid is added to 3.5 g of magnesium carbonate. If the sample of magnesium carbonate is kept constant, which conditions will not increase the initial rate of reaction?

14. At 25°C, 100 cm3 of 1.0 mol dm–3 hydrochloric acid is added to 3.5 g of magnesium carbonate. If the sample of magnesium carbonate is kept constant, which conditions will not increase the initial rate of reaction?

15. Which statement is correct with regard to the catalysed and uncatalysed pathways for a given reaction?  

16. Which changes increase the rate of a chemical reaction? I. Increase in the concentration of an aqueous solution II. Increase in particle size of the same mass of a solid reactant III.    Increase in the temperature of the reaction mixture

17. Excess magnesium, was added to a beaker of aqueous hydrochloric acid. A graph of the mass of the beaker and contents was plotted against time (line 1).   What change in the experiment could give line 2?

18. Which quantities in the enthalpy level diagram are altered by the use of a catalyst?