Question detail

For Amounts of substances in equations (HT only), which option best supports this Unit 4.3 objective: (HT only) Calculate masses of reactants from a balanced symbol equation and a given mass of another substance?

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

Use of amount of substance in relation to masses of pure substances

Question

A. 370 g
B. 186 g
C. 250 g
D. 300 g

Answer

The answer is 370 g.

Explanation

The correct option is 370 g. This uses Moles From Mass because the objective is about (HT only) Calculate masses of reactants from a balanced symbol equation and a given mass of another substance. The reasoning belongs to Amounts of substances in equations (HT only) within Use of amount of substance in relation to masses of pure substances, so it should not be confused with nearby quantitative ideas such as mass, moles, concentration, yield, atom economy, or gas volume unless those are named in the objective. Use the focus term HT only to keep the answer aligned with AQA GCSE Chemistry 8462 Unit 4.3. The other options are weaker because they either use the wrong formula, the wrong unit, a vague relationship, or the wrong quantitative context.

Common mistake

Confusing Mass and Moles

Students often confuse the mass of a substance with the number of moles when calculating the masses of reactants from a balanced symbol equation.

To fix this, remember to use the formula that relates mass, moles, and relative formula mass: mass = moles x Mr. Ensure you calculate the number of moles first before converting to mass. Keep the correction anchored to Amounts of substances in equations (HT only); check formula, substitution, calculation, final answer, and unit where relevant.

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