Question detail
What is the effect on the rate of a reaction if the concentration of a first-order reactant is doubled?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Rate equations (A-level only)
Question
- A. The rate doubles.
- B. The rate quadruples.
- C. The rate remains the same.
- D. The rate decreases.
Answer
The rate doubles.
Explanation
The correct option is The rate doubles.. The rate doubles. is the best answer because it directly supports the AQA A-Level Chemistry objective to write rate equations using experimentally determined orders. This reasoning is anchored to Rate equations and orders (A-level only) in Rate equations (A-level only), and it separates rate equation from similar A-Level ideas rather than relying on a vague recall statement. Other options are weaker if they use the wrong evidence, calculation, mechanism, observation, unit, or conclusion for this subtopic.
Common mistake
Incorrect Rate Equation Formation
Students often confuse the order of reaction with the coefficients in the balanced equation when writing rate equations.
To write the correct rate equation, identify the order of each reactant based on experimental data, not the coefficients. For example, if the rate law is rate = k[A]^2[B]^1, this indicates that the reaction is second order with respect to A and first order with respect to B. Ensure to use the correct orders derived from initial rate data.
Related flashcards
Flashcard 1 of 5
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.