Ch 6 Review Understanding Concepts 1 pressure or volume conductivity absorbency of light 2 concentration temperature catalysis chemical nature of reactants 3 Additional surface area 18 1 cm2 Total surface area 24 cm2 Proportional change in surface area 26 4cm2 4 The rate would be multiplied by a factor proportional to the surface area change r 4 20 mL s r 80 mL s 4 a rate increases b rate decreases c rate increases d rate increases 5 a r r 1 47 mL s b i With a 5 C increase in temperature the rate could be doubled and the time halved ii Without the catalyst the reaction might be imperceptibly slow 6 a r k ClO2 aq 2 OH aq b This is a third order reaction c The rate would quadruple d The rate would double 7 a When we compare Trials 1 and 2 we see that as Cl2 is doubled rate is multiplied by 2 therefore rate depends on Cl2 1 When we compare Trials 2 and 3 we see that as NO is doubled rate is multiplied by 4 therefore rate depends on NO 2 Overall r k Cl2 1 NO 2 b The rate determining step is most likely to be 2 NO g Cl2 g product or intermediate c k NO 2 r Cl2 k 18 L2 mol2 s d r k NO 2 Cl2 18 L2 mol2 s 0 30 mol L 2 0 40 mol L r 0 65 mol L s 1 8 102 mol L s 0 10 mol L 2 0 10 mol L 8 a Half life is the amount of time for one half the mass of a radioisotope to decay b 14 0 a is four half lives The percentage remaining is 100 1 4 6 25 11 a There are generally one two or three particles involved in each elementary step b Collisions of more particles at the same point in time and space are much less probable as the number of particles increases Four body collisions are effectively impossible as contributors to a reaction process 12 a A catalyst might be consumed in one step of a mechanism as long as it is regenerated in a subsequent step b Homogeneous catalysts like acid in aqueous solution are in the same phase as reactants Heterogeneous catalysts like platinum in gases are in different phases from reactants 13 a catalyst necessary in first step but regenerated Cu2 aq intermediates produced but then consumed Cu aq I aq CuSO4 aq b S2O8 2 aq 2 I aq I2 aq 2 SO4 2 aq c Since the I aq is not part of the rate determining slow step increasing its concentration will have no effect on the overall rate d Since the S2O8 2 aq is part of the rate determining slow step increasing its concentration will increase the overall rate 15 a When we compare Trials 1 and 2 we see that as W is doubled rate is unchanged therefore rate depends on W 0 When we compare Trials 1 and 3 we see that as X is doubled rate is multiplied by 2 therefore rate depends on X 1 When we compare Trials 1 and 4 we see that as Y is doubled rate is multiplied by 4 therefore rate depends on Y 2 Overall r k X 1 Y 2 b The rate determining step is X 2Y products c A possible mechanism might be X 2Y XY2 slow XY2 W WXY2 fast WXY2 X Z fast 16 a When we compare Trials 1 and 2 we see that as Hbn is doubled rate is multiplied by 2 therefore rate depends on Hbn 1 When we compare Trials 2 and 3 we see that as CO is tripled rate is multiplied by 3 therefore rate depends on CO 1 b The overall order is two c Overall r k Hbn 1 CO 1 d The carbon monoxide rate constant might be expected to be larger than the oxygen rate constant because it seems to bind so quickly to hemoglobin On the other hand as will be discovered in the next unit the more significant factor is the equilibrium constant for the binding reaction which is much larger for carbon monoxide than for oxygen