Beatty 3.1_ROR_(W1)_2023_Answers

1 Beatty Secondary School Science Department (Chemistry Unit) Chemistry 6092 Name: ___________________________________ ( ) Date: _______________ Class: 4E___ TOPIC: SPEED / RATE OF REACTION (WORKSHEET 1) – FACTORS Learning Objectives: (a) Describe the effect of concentration, pressure, particle size and temperature on the speeds of reactions and explain these effects in terms of collisions between reacting particles. (b) Define the term cata lyst and describe the effect of catalysts (including enzymes) on the speeds of reactions. (c) Explain how pathways with lower activation energies account for the increase in speeds of reactions. (d) State that some compounds act as catalysts in a range of industrial processes and that enzymes are biological catalysts. Multiple-Choice Questions 1 Which factor does not affect the speed of a chemical reaction? A concentration of reactant B colour of reactant C surface area of reactant D temperature of reactant ( B ) 2 Which solution would react the fastest if added to the same amount of magnesium? A 4 g of acid in 50 cm3 of water B 10 g of acid in 100 cm3 of water C 40 g of acid in 250 cm3 of water D 100 g of acid in 1000 cm3 of water ( C ) 3 Which statement best explains why coal dust forms an explosive mixture with air? A Coal dust catalyses the explosion. B Coal dust has a large surface area. C Crushing coal breaks chemical bonds. D Crushing coal releases hydrogen from compounds in coal. ( B ) 4 Dilute sulfuric acid reacts with copper(II) oxide to form copper(II) sulfate and water. What would not alter the rate of reaction? A The concentration of the sulfuric acid. B The pressure at which the reaction takes place. C The size of the particles of copper(II) oxide. D The temperature of the reacting mixture. ( B )

2 5 A teacher wanted to demonstrate a reaction between an acid and a soli d reactant, but it was too violent to be safe. Which of these changes would make the reaction safer to demonstrate? acid temperature acid concentration size of solid reactant A lower lower larger B lower lower smaller C higher higher larger D higher higher smaller ( A ) 6 Which reaction is the fastest? ( D ) 7 Which factor decreases the activation energy of a reaction? A addition of a catalyst B increase in concentration of reactants C increase in pressure D increase in temperature ( A ) 8 The oxide of an element J increases the rate of decomposition of hydrogen peroxide. At the end of the reaction the oxide J is chemically unchanged. Which details are those of J? proton number mass number A 18 40 B 20 40 C 25 55 D 53 127 ( C )

3 9 The enthalpy diagram shows an