Chem Rate of Rxn Ws2

Secondary 4 Express Pure Chemistry – Rate of Reaction Worksheet 2 Page 1 of 12 Name: _____________________( ) Class: _______ Date ________ 1 Zinc reacts with hydrochloric acid. Which solution would give the fastest initial rate of reaction? A 80 g of HCl in 1000 cm3 of water B 40 g of HCl in 1000 cm3 of water C 20 g of HCl in 100 cm3 of water D 8 g of HCl in 50 cm3 of water 2 Glucose is converted into ethanol and carbon dioxide by fermentation. The rate of reaction can be measured by the volume of carbon dioxide gas produced per minute. The graph shows how the volume of carbon dioxide produced per minute changes with temperature. volume of carbon dioxide gas produced per minute 0 10 20 30 40 50 60 70 temperature / oC From the graph, which statement is correct? A The reaction is slowest at 0oC. B The reaction is fastest at about 60oC. C The rate of reaction always increases when the temperature increases. D The rate of reaction is greatest at about 40oC. 3 Which section of the Periodic Table is most likely to contain an element suitable for use as a catalyst in an industrial process? A the alkali metals B the halogens C the noble gases D the transition elements

Secondary 4 Express Pure Chemistry – Rate of Reaction Worksheet 2 Page 2 of 12 4 In terms of particle theory, why do smaller pieces of solid react more quickly with liquid reactant than an equal mass of larger pieces of solid? A There are stronger forces between the solid and the colliding particles . B The solid has a larger surface area for particles of the liquid to collide with. C The particles of the liquid collide with each other more frequently. D The particles of liquid do not have to break so many bonds in the solid. 5 Magnesium ribbon was reacted with hydrochloric acid. The volume of hydrogen gas produced was measured for the first 40 seconds. 0 10 20 30 40 50 0 5 10 15 20 25 30 35 40 time from start of reaction / s volume of hydrogen gas / cm3 What was the average rate of reaction is terms of volume of gas produced per second? A 0.8 cm3/s B 5.0 cm3/s C 8 cm3/s D 80 cm3/s 6 Copper(II) oxide powder catalyses the decomposition of hydrogen peroxide. In a laboratory experiment, copper(II) oxide was mixed with aqueous hydrogen peroxide in a beaker. What was present in the beaker when the reaction was complete? A a colourless liquid and a black solid B a blue liquid only C a shiny brown solid and a colourless liquid D a black solid only

Secondary 4 Express Pure Chemistry – Rate of Reaction Worksheet 2 Page 3 of 12 7 In the graph, curve Y represents the results of reacting 1.0 g of magnesium granules with an excess of acid at 40oC. Y total volume of gas (at r.t.p.) Z time Which changes could produce curve Z? A using 1.0 g of magnesium granules and an excess of acid at 30oC B using 1.0 g of magnesium powder and an excess of acid at 30oC C using 0.5 g of magnesium granules and an excess of acid at 50oC D using 0.5 g of magnesium granules and an excess of acid at 30oC 8 When a piece of calcium metal is added to dilute hydrochloric acid, the reaction is seen to be faster after 60 seconds than after only 10 seconds. What could explain this observation? A Heat is produced in the reaction, which raises the temperature. B The concentration of the hydrochloric acid increases during the reaction. C Hydrochloric acid is a catalyst. D The piece of calcium is smaller at 60 seconds than at 10 seconds. 9 In which reaction is the pressure not likely to affect the rate of reaction? A H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(l) B CuO(s) + H2(g)  Cu(s) + H2O(l ) C 3H2(g) + N2(g)  2NH3(g) D Fe2O3(s) + 3CO(g)  2Fe(s) + 3CO2(g)

Secondary 4 Express Pure Chemistry – Rate of Reaction Worksheet 2 Page 4 of 12 10 excess sulphuric acid cotton wool granules of flask zinc metal balance Which graph would be obtained for the results of the experiment shown above? balance A reading B C D 0 time Section B: Structured Questions

Secondary 4 Express Pure Chemistry – Rate of Reaction Worksheet 2 Page 5 of 12 1 In an experiment (Experiment I), a volume of 0.5 mol/dm3 hydrochloric acid was added to marble chips in a flask. The marble was in excess. A graph of volume of gas produced against time is shown in the diagram. 100 volume of gas / cm3 80 60 Experiment I 40 20 0 ½ 1 1½ 2 2½ 3 time / minutes (a) Write the equation, with state symbols, for the reaction. ............................................................................................................................................ [2] (b) Explain the shape of the graph between 2 and 2½ minutes from the start. ............................................................................................................................................. [2] (c) State and explain the difference in the rate of reaction at ½ minute and at 1 minute from the start. (i) difference in rate: ....................................................................................................................................... (ii) explanation: ....................................................................................................................................