Question detail

Case 39 ratio-step. A balanced equation is used in a calculation. Which interpretation is safest? Focus on Distinguish atom economy percentage yield when evaluating in Atom economy, not on a neighbouring Unit 4.3 idea.

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

At a glance

MCQ

Type

practice

Style

Topic

Yield and atom economy of chemical reactions (chemistry only)

Question

  1. A. Case 39 ratio-step: Use coefficients as mole-ratio information, not formula subscripts for Distinguish atom economy percentage yield when evaluating
  2. B. Case 39 ratio-step: Treat subscripts inside a formula as reacting mole ratios (Atom economy)
  3. C. Case 39 ratio-step: Assume every reactant and product always has a 1 to 1 ratio (Distinguish atom economy percentage yield when evaluating)
  4. D. Case 39 ratio-step: Use the largest mass as the limiting amount without mole comparison (Yield and atom economy of chemical reactions (chemistry only))

Answer

The correct option is Case 39 ratio-step: Use coefficients as mole-ratio information, not formula subscripts for Distinguish atom economy percentage yield when evaluating.

Explanation

The correct option is Case 39 ratio-step: Use coefficients as mole-ratio information, not formula subscripts for Distinguish atom economy percentage yield when evaluating. It supports the approved learning objective by keeping the method tied to Distinguish atom economy percentage yield when evaluating in Atom economy. The other options are incorrect because they either use the wrong quantitative relationship, lose the required unit, confuse coefficients with subscripts, or report an answer without a complete worked method.

Common mistake

Confusing Atom Economy with Percentage Yield

Students often confuse atom economy with percentage yield, thinking they represent the same concept.

To fix this, remember that atom economy measures the efficiency of a reaction in terms of how much of the starting materials are converted into useful products, while percentage yield compares the actual product obtained to the theoretical maximum. Keep the correction anchored to Atom economy; check formula, substitution, calculation, final answer, and unit where relevant.

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recall MCQ 39: yield when evaluating a reaction. | Yield and atom… | ExamCompanion