Rate of Reaction

Question 3:A protein-digesting enzyme is used to study the effect of temperature on the rate of protein digestion in milk. The set-up of the apparatus is shown in Figure 1. The time measured is the time taken for the enzyme to digest all the protein and the milk becomes clear, that is until the ‘X’ … Read more

Question 1:Rate of reaction measures the change in the quantity of reactants or products per unit time.(a) State three units for measuring the quantity of substances.(b) For each unit of measurement for the quantity of substances in 1(a), state the corresponding unit for the rate of reaction. Answer:(a) g (mass); cm3 (volume); mol dm–3 (concentration)(b) … Read more

Question 1:The Kinetic Theory of Matter states that the particles in matter are constantly moving. Mark (√) for true statements and (X) for false statements.(a) At constant temperature, all particles move with the same velocity. (   )(b) Particles in solids are moving freely. (   )(c) Collisions between particles are random. (   )(d) The kinetic energy … Read more

Question 1:Fill in the blanks.(a) Meat cooks faster if it is cut into _________ sizes.(b) In the refrigerator, the __________ temperature decreases the growth of bacteria that causes food decay.(c) Food cooks faster in a pressure cooker because of high ____________.(d) Coal burns faster in small chips because of the large surface area that is … Read more

Question 1:The rate of reaction is affected by various factors.(a) State four factors that would affect the rate of reaction.(b) Zinc, Zn reacts with excess sulphuric acid, H2SO4 according to the following equation:State four ways to speed up the reaction. In your answer, state the manipulated and the fixed variables. Answer: (a) Concentration of reactant … Read more

Activity 7.4:Discussing the solution involving the rate of reactions and determine the variables involved in the reactionsAs a group, solve the following problems:1. Figure 7.16 shows the graph of volume of carbon dioxide against time for the two experiments, I and II.Table 7.7 shows the conditions of the two experimentsSuggest two ways to carry out … Read more

Experiment 7.4:Aim: To investigate the effect of catalyst on the rate of reaction.Problem statement: How does the presence of catalyst affect the rate of reaction?Hypothesis: Presence of catalyst increases the rate of reaction.Variables:(a) Manipulated : Presence of catalyst(b) Responding : Rate of reaction(c) Fixed : Mass of manganese(IV) oxide, MnO2, temperature and volume of hydrogen … Read more

Experiment 7.3:Aim: To investigate the effect of temperature on the rate of reaction.Problem statement: How does temperature affect the rate of reaction?Hypothesis: The higher the temperature of the sodium thiosulphate solution, Na2S2O3, the shorter the time taken for the ‘X’ mark to disappear from view.Variables:(a) Manipulated : Temperature of sodium thiosulphate solution, Na2S2O3(b) Responding : … Read more

Experiment 7.2:Aim: To investigate the effect of concentration of reactants on the rate of reaction.Problem statement: How does the concentration of the reactants affect the rate of reaction?Hypothesis: The higher the concentration of sodium thiosulphate solution, Na2S2O3, the shorter the time taken for the ‘X’ mark to disappear from view.Variables:(a) Manipulated : Concentration of sodium … Read more

Question 1:Explain the meaning of rate of reaction. Answer:Rate of reaction is the change in the quantity of a reactant per unit time or the change in the quantity of product per unit time. Question 2:Classify the following reactions as fast or slow:(a) Photosynthesis (b) Combustion of petrol in car engines (c) Rusting of iron … Read more