Beatty 15.2_ROR_(W2)_2023_Answers

1 Beatty Secondary School Science Department (Chemistry Unit) Chemistry 6092 Name: ___________________________________ ( ) Date: _______________ Class: 4E___ TOPIC: SPEED / RATE OF REACTION (WORKSHEET 2) – GRAPH & PLANNING Learning Objectives: (a) Suggest a suitable method for investigating the effect of a given variable on the speed of a reaction. (b) Interpret data obtained from experiments concerned with speed of reaction. Multiple-Choice Questions 1 Dilute hydrochloric acid was reacted with magnesium ribbon and the volume of hydrogen gas evolved was measured for the first 80 seconds. What was the average rate of production of hydrogen? A 0.4 cm3/s B 2.5 cm3/s C 4 cm3/s D 40 cm3/s ( A ) 2 Two reactants were mixed together in a beaker and the mass of the beaker and its contents was recorded at regular time intervals. A graph of mass plotted against time is shown below. Which of the following are possible reactants? A sodium hydroxide and hydrochloric acid B copper sulfate and zinc C copper(II) carbonate and hydrochloric acid D sodium hydroxide and copper(II) sulfate ( C )

2 3 A student adds marble chips to hydrochloric acid. The mass of flask and contents is measured at regular time intervals. Which graph shows the result? ( A ) 4 The rate of the reaction between a given mass of calcium carbonate and an excess of hydrochloric acid is studied by collecting the carbon dioxide in a gradu ated syringe. The results are shown in the graph. How much time is required for half the calcium carbonate to react? A 0.95 min B 1.5 min C 2.0 min D 3.0 min ( A )

3 5 In two separate experiments, the reaction of powdered calcium carbo nate with an excess of dilute hydrochloric acid is investigated. The powder used in experiment 1 is finer than that used in experiment 2. All other conditions are identical in both experiments. Which graph shows the results? ( D ) 6 In two se parate experiments, a substance is decomposed and the gas evolved is collected. The graph shows the total volume of gas collected against time for each experiment. Which graph shows how the speed of reaction varies with time in each experiment? ( A )

4 Use the following information to answer Questions 7 to 10. In an experiment, a strip of magnesium ribbon is reacted with excess dilute hydrochloric acid. Curve X is obtained when the volume of hydrogen gas given off during the reaction is plotted against time. Which of the following changes to the experiment would produce the graphs, A, B, C or D? 7 Only half the amount of magnesium is reacted with excess acid. ( D ) 8 The acid is diluted to half of its original concentration but is still in excess. ( C ) 9 The strip of magnesium ribbon is grounded i