A 10 g sample of starch (molar mass 162 g·mol⁻¹) is completely hydrolyzed by amylase to glucose (molar mass 180 g·mol⁻¹). Calculate the mass of glucose formed.
Answer
11.1 g of glucose
The correct answer is 11.1 g of glucose — State the mass of glucose formed.
Step-by-step solution
- Calculate moles of starch: 10 g ÷ 162 g·mol⁻¹ = 0.06173 mol.
- Assuming complete hydrolysis, one mole of starch yields one mole of glucose molecules (stoichiometrically 1:1 for this problem).
- Convert moles of glucose to mass: 0.06173 mol × 180 g·mol⁻¹ = 11.1114 g.
- Round to three significant figures: 11.1 g.
- State the mass of glucose formed.
Common mistake: Using the wrong molar mass for glucose or forgetting to round appropriately.
Concept tested: Stoichiometry of carbohydrate digestion
Published · How this solution was prepared and checked
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