Question

C. Sucrose is readily hydrolyzed i.e. broken down back to glucose and fructose by reaction with acidic solution. The hydrolysis can be monitored by measuring the angle of rotation of plane-polarized light passing through the solution because the concentration of sucrose can be inferred from this angle. An experiment on the hydrolysis of sucrose in 0.5 M HCl(aq) produced the following data: t/min 0 (sucrose) 0.316 /M 14 0.300 39 0.274 60 80 0.256 0.238 110 140 0.211 0.190 170 0.170 210 0.146 Assume that the reaction is first-order in sucrose, and determine the rate constant of the reaction and the half-life of sucrose. 4 marks) Role in TM 300 h = 1.21.183 m = 1186.8 minutes = (3.71x10 ming d. The rate law for the hydrolysis of sucrose is found to be rate = k[H"sucrose). The initial rate of sucrose hydrolysis is measured in a solution that is 0.01M H. 1.0M sucrose, 0.1M fructose, and 0.1M glucose. How does the rate change if i. (sucrose) is changed to 2.5M (show work)? (2 marks) ii. (sucrose], [fructose), and (glucose) are all changed to 0.5M (show work)? (2 marks) iii. [H'] is changed to 0.0001M (show work)? (2 marks) iv. (sucrose) and (H') are both changed to 0.1M (show work)? (2 marks)

Part D is what is needed

Answer 1

d) Rate = k [ht] {sucrose] Initially, [H+] = 0.01 Csucrosol om, fruct - [glucore] =0nM If the sucrose is changed to 2.5 m, that means it has increased by a factor of a 2.5 Now, Rate is directly proportional to (sucroses Rate also increased by a factor of 2.5 . aloo k = 3.718 10-3 minu Initial rate = 3.718los xo.olx1.0 371X10 $ MIS Increased rate = 3.71x10 3 x 0.01x2.5 = 9.28 x 105 M/ ') e fructoseI and glucose are not pre in the rate law. So, changing their concent trations has no effect on the rate. ] -0.5M [ sucrose reduced by a factor factor a 2. The New of £. es by fact rate rate also decreases by a : 3.718 103 xool xo.5 = 1.85 yio 5 m/s New rate = 3.71x10 3 x 0.0ool xolo = 3.71X 107 m/s. decreases by a factor of 100. . Rate New rate = 3.71810 xo.lxool m/s = 3.71X10 - unchanged. Rate remains

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