Beatty 15.3_ROR_REVIEW(W3)_2023_Answers

1 Beatty Secondary School Science Department (Chemistry Unit) Chemistry 6092 Name: ___________________________________ ( ) Date: _______________ Class: 4E___ TOPIC: SPEED / RATE OF REACTION REVIEW (WORKSHEET 3) Multiple-Choice Questions 1 Two gases Q and R react according to the equation. Q (g) + R (g) → T (g) The reaction mixture is placed in a container at room temperature. Which action can speed up the formation of gas T? A Adding an inert gas to the mixture. B Using a bigger container. C Lowering the piston in the container. D Placing the container in water at 5 °C. ( C ) 2 Catalase is an enzyme commonly found in living cells. It increases the rate of decomposition of hydrogen peroxide found in human bodies into water and oxygen gas. Which statement about catalase is correct? A It operates effectively at all temperatures. B It operates most effectively over a certain range of pH. C It increases the activation energy of the decomposition of hydrogen peroxide. D It increases the yield of products from the decomposition of hydrogen peroxide. ( B ) 3 Hydrogen peroxide is catalytically decomposed by manganese( IV) oxide. To study the effect of the concentration of the solutions on the rate of reaction, the total volume of oxygen evolved was recorded against time. Three experiments were performed with a fixed mass of catalyst but with (i) 50 cm3 of 2.0 mol/dm3 hydrogen peroxide (ii) 100 cm3 of 1.0 mol/dm3 hydrogen peroxide (iii) 100 cm3 of 2.0 mol/dm3 hydrogen peroxide On the graph above, which of the curves X, Y, Z relate to the solutions (i), (ii), (iii)? (i) (ii) (iii) A X Y Z B X Z Y C Z X Y D Y Z X ( D ) mixture of Q and R

2 4 Calcium carbonate was reacted with an excess of dilute hydrochloric acid at room temperature. CaCO3 + 2HCl → CaCl2 + H2O + CO2 Two experiments were carried out. Experiment 1: 100 g of calcium carbonate in large lumps. Experiment 2: 50 g of calcium carbonate as a fine powder. Which graph is correct? ( D ) 5 A student investigated the rate of reaction of marble chips with excess dilute hydrochlor ic acid, by measuring the change in mass over a period of time. The experiment was then repeated using powdered calcium carbonate. How did the initial rate and the final mass change when powdered calcium carbonate was used? initial rate final mass A faster lesser B faster unchanged C slower unchanged D unchanged unchanged ( B ) 6 In the Contact Process, traces of vanadium( V) oxide is added in the oxidation of sulfur dioxide to sulfur trioxide in the equation as shown. 2SO2 + O2 ⇌ 2SO3 Which statement(s) correctly explain(s) why vanadium(V) oxide is added? 1 It acts as an oxidising agent to oxidise sulfur dioxide. 2 It ensures that the yield would be 100%. 3 It removes acidic