Rate of Reaction (O-Level Chemistry 5070)

What is the meaning of the rate of reaction?

• Decrease in amount of product

• Decrease in amount of product against time

• Increase in amount of products against time

• Increase in amount of reactants against time

The following equation shows the reaction between calcium carbonate, CaCO₃ and hydrochloric acid, HCl:

CaCO₃ (aq) + 2HCl (aq) → CaCl₂ (aq) + CO₂ (g)_­­ + H₂O (l)

Which of the following is the suitable method to determine the rate of reaction?

• Change in the temperature of the solution with time

• Change in the volume of carbon dioxide gas with time

• Change in the mass of water with time

• Change in the concentration of hydrochloric acid with time

Which of the following is the meaning of activation energy?

• The maximum energy that the particles need to produce effective collision

• The amount of energy used by the particles during a collision

• The minimum amount of energy that particles must have in order to react

• The amount of kinetic energy of molecules during a collision

Which factor(s) increase the rate of a reaction?

• increasing temperature

• increasing concentration

• increasing total surface area

• All of these

Diagram 4 shows the graph of volume of carbon dioxide gas against time when 5 g of marble chips is added to 50 cm³ of 0.2 mol dm^-3 hydrochloric acid. At what time the rate of reaction the highest?

• t1

• t2

• t3

• t4

Why does a higher temperature increase the rate of a reaction?

• It increases both the frequency collision and energy of reactant particles

• It only increases the frequency of collision

• It only increases the energy of reactant particles

• It reduces the activation energy of the reaction

Diagram 7 shows a graph of the volume of gas produced against time for the reaction between zinc granules and hydrochloric acid. The gradient of the graph decreases with time because

• catalyst is not used

• volume of mixture decreases

• temperature of reaction decreases

• concentration of hydrochloric acid decreases

Which of the following explains the meaning of effective collision?

• The collision where its energy is less than the activation energy

• The collision that has a low energy

• The collision which takes place before a reaction

• The collision that causes a reaction

The equation represents the reaction between sodium carbonate and hydrochloric acid.

Na₂CO₃ + 2 HCl → 2 NaCl + H₂O + CO₂

The mass of the beaker and its contents is plotted against time.

Which graph represents what happens when sodium carbonate reacts with an excess of dilute hydrochloric acid?

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Magnesium reacts with acid to produce hydrogen gas, H₂.Which solution would give the highest initial rate of reaction?

• 100 cm³ of 1.0 mol dm^-3 of nitric acid, HNO₃

• 100 cm³ of 1.0 mol dm^-3 of hydrochloric acid, HCl

• 100 cm³ of 1.0 mol dm^-3 of sulphuric acid, H₂SO₄

• 100 cm³ of 1.0 mol dm^-3 of ethanoic acid, CH₃COOH