Question detail

A reaction produces 50 g of product from a theoretical yield of 80 g. What is the percentage yield of the reaction?

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Kinetics

Question

A. 62.5%
B. 75%
C. 80%
D. 50%

Answer

62.5%

Explanation

To calculate the percentage yield, we use the formula: percentage yield = (actual yield / theoretical yield) x 100. Here, actual yield = 50 g and theoretical yield = 80 g. Therefore, percentage yield = (50 g / 80 g) x 100 = 62.5%.

Common mistake

Misunderstanding Concentration Effects

Students often confuse concentration with the total amount of substance, leading to incorrect conclusions about how concentration affects reaction rate.

To correctly explain how concentration affects collision frequency and rate, use the formula for collision frequency: collision frequency ∝ concentration. For example, if the concentration of reactants is doubled, the collision frequency also doubles, leading to an increased reaction rate. Therefore, if the initial concentration is 0.5 mol/dm³ and the new concentration is 1.0 mol/dm³, the substitution would be: collision frequency ∝ 1.0 mol/dm³ / 0.5 mol/dm³ = 2. The answer is that the collision frequency doubles, which increases the rate of reaction.

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