Chapter-7 Rates of Reaction — Online MCQ Test
CHEMISTRY · Grade 10 · IGCSE cambridge
Practice Chapter-7 Rates of Reaction with a free chapter-wise online MCQ test.
This chapter covers: Factors affecting reaction rate collision theory catalysts and interpreting rate experiments..
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Chapter-7 Rates of Reaction — Important Questions & Answers
What is the definition of rate of reaction?
- A. The speed at which reactants are converted into products
- B. The total amount of product formed in a reaction
- C. The temperature at which a reaction occurs
- D. The energy required to start a reaction
Answer: A. The speed at which reactants are converted into products
Rate of reaction is defined as the speed at which reactants are converted into products, typically measured as change in concentration per unit time.
Rate of reaction is defined as the speed at which reactants are converted into products, typically measured as change in concentration per unit time.
Which of the following is NOT a factor that affects the rate of reaction?
- A. Temperature
- B. Concentration of reactants
- C. Colour of the reaction vessel
- D. Presence of a catalyst
Answer: C. Colour of the reaction vessel
The colour of the reaction vessel does not affect the rate of reaction. The main factors are temperature, concentration, surface area, and catalysts.
The colour of the reaction vessel does not affect the rate of reaction. The main factors are temperature, concentration, surface area, and catalysts.
When the temperature of a reaction is increased, the rate of reaction increases because:
- A. The number of reactant particles decreases
- B. Particles move faster, increasing collision frequency and energy
- C. The activation energy of the reaction decreases
- D. The volume of the reaction vessel increases
Answer: B. Particles move faster, increasing collision frequency and energy
Increasing temperature causes reactant particles to move faster, resulting in more frequent collisions and a greater proportion of collisions with energy exceeding the activation energy.
Increasing temperature causes reactant particles to move faster, resulting in more frequent collisions and a greater proportion of collisions with energy exceeding the activation energy.
A student investigates how temperature affects the reaction between marble chips and dilute hydrochloric acid. Which method would give the most accurate rate measurement?
- A. Recording the time taken for the mixture to change colour
- B. Measuring the volume of gas produced at regular time intervals using a gas syringe
- C. Observing when bubbles stop forming
- D. Estimating the intensity of fizzing visually
Answer: B. Measuring the volume of gas produced at regular time intervals using a gas syringe
Using a gas syringe to measure gas volume at regular intervals provides quantitative, accurate data that can be plotted to determine reaction rate, unlike subjective visual observations.
Using a gas syringe to measure gas volume at regular intervals provides quantitative, accurate data that can be plotted to determine reaction rate, unlike subjective visual observations.
Consider the reaction: A + B → Products. If the rate law is found to be: Rate = k[A]²[B], which statement is TRUE?
- A. The reaction is first order with respect to A and zero order with respect to B
- B. The reaction is second order with respect to A and first order with respect to B, making it third order overall
- C. Doubling [A] will increase the rate by a factor of 2, while doubling [B] will double the rate
- D. The rate constant k has units of mol⁻¹ dm³ s⁻¹
Answer: B. The reaction is second order with respect to A and first order with respect to B, making it third order overall
The exponents in the rate equation indicate the order: [A]² means 2nd order in A, [B] means 1st order in B, giving 3rd order overall. Doubling [A] increases rate 4-fold; doubling [B] doubles the rate.
The exponents in the rate equation indicate the order: [A]² means 2nd order in A, [B] means 1st order in B, giving 3rd order overall. Doubling [A] increases rate 4-fold; doubling [B] doubles the rate.