Rates of Reaction Quiz
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5 questions, one answer each
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1. A student carries out a reaction and finds that 8 g of reactant is used in 40 seconds. What is the rate of reaction?
- A. 0.2 g/s
- B. 0.5 g/s
- C. 5 g/s
- D. 320 g/s
2. Which method would be most suitable for measuring the rate of a reaction that produces a coloured precipitate?
- A. Measuring the volume of gas collected
- B. Measuring the change in mass of the container
- C. Observing the colour change or using a colorimeter to measure absorbance
- D. Measuring the temperature change
3. According to collision theory, increasing the concentration of a reactant increases the rate of reaction because:
- A. It increases the activation energy of the reaction
- B. It increases the frequency of collisions between reactant particles
- C. It decreases the temperature of the system
- D. It reduces the need for a catalyst
4. A reaction is carried out at two different temperatures. At the higher temperature, the rate increases significantly. According to collision theory, this is because the higher temperature causes:
- A. Only an increase in the frequency of collisions
- B. Only an increase in the proportion of particles with sufficient activation energy
- C. Both an increase in collision frequency and an increase in the proportion of particles with energy ≥ activation energy
- D. A decrease in the activation energy of the reaction
5. A concentration-time graph for a reaction shows a curve. To find the rate of reaction at exactly 20 seconds, what should be done?
- A. Calculate the gradient using two points on the curve far apart in time
- B. Draw a tangent to the curve at the 20-second point and calculate its gradient
- C. Measure the total change in concentration from start to finish
- D. Read the concentration value directly from the y-axis at 20 seconds