NJC Class Quiz 4 Kinetics QP

National Junior College SH1 H1 Chemistry 1 SH1 Exit Quiz (Reaction Kinetics) Name: ____________________________________ Duration: 20 min 1 Sucrose is a sugar produced in plants such as sugarcane and sugar beet where it is extracted and refined for use as a sweetener in food and beverage. In sucrose, the bond between the monomers glucose and fructose can be broken via a hydrolysis reaction with water. The hydrolysis is so slow that a solution of sucrose can be stored for a long period of time at room temperature with negligible change. (a) Enzymes like sucrase have specific activity. When a very small amount of sucrase is added to a solution of sucrose, however, the hydrolysis reaction will proceed rapidly. (i) Explain what is meant by the term specific activity of an enzyme. ................................ ................................ ................................ ............................... ................................ ................................ ................................ ........................... [1] The graph in Fig. 1.1 shows how the initial rate varies with sucrose concentration for the hydrolysis reaction where a very small amount of sucrase was added. Fig. 1.1 (ii) “At very high concentrations, the order of reaction with respect to [sucrose] is 1.” Comment on the validity of this statement and explain your answer using Fig. 1.1. ................................ ................................ ................................ ............................... ................................ ................................ ................................ ............................... ................................ ................................ ................................ ........................... [1] initial rate of reaction [sucrose] 11

National Junior College SH1 H1 Chemistry 2 (iii) Using a Boltzmann distribution curve, explain why the addition of sucrase increases the rate of the hydrolysis reaction. ................................ ................................ ................................ ............................... ................................ ................................ ................................ ............................... ................................ ................................ ................................ ............................... ................................ ................................ ................................ ............................... ................................ ................................ ................................ ........................... [3]

National Junior College SH1 H1 Chemistry 3 (b) The hydrolysis reaction of sucrose can also be accelerated with acids such as hydrochloric acid. The