Question detail
Calculate the number of moles in 50 grams of sodium chloride (NaCl). The relative atomic masses are Na = 23 and Cl = 35.5.
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At a glance
Question
Type
exam_style
Style
Topic
Amount of substance
Question
Calculate the number of moles in 50 grams of sodium chloride (NaCl). The relative atomic masses are Na = 23 and Cl = 35.5.
Answer
0.428 moles. This answer is anchored to The mole and the Avogadro constant. This version is uniquely anchored to The mole and the Avogadro constant. Retrieval anchor: A-level cue 27b2eb59.
Explanation
0.428 moles. This answer is anchored to The mole and the Avogadro constant. is correct because it supports the objective: Use standard form, appropriate units and significant figures in mole calculations.. The reasoning stays within The mole and the Avogadro constant and avoids drifting into a similar A-Level Chemistry idea. This item is treated as conceptual revision rather than a formal calculation item because the validated answer is an explanation or option choice, not a worked numerical response.
Common mistake
Common Mistake in Mole Calculations
Students often forget to convert volumes from cm³ to dm³ when calculating concentrations, leading to incorrect results.
Always convert volumes to dm³ before using the formula for concentration. For example, if the volume is 250 cm³, convert it to dm³ by dividing by 1000: 250 cm³ = 0.250 dm³. Then use the formula: concentration = mass / volume. If the mass of solute is 5 g, the calculation would be: concentration = 5 g / 0.250 dm³ = 20 g/dm³.
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