Question detail
Calculate the number of moles in 50 grams of sodium chloride (NaCl). The relative formula mass (Mr) of NaCl is 58.5 g/mol.
Try the question, check the answer, then read the explanation to understand the curriculum point.
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 formula mass (Mr) of NaCl is 58.5 g/mol.
Answer
0.857 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 c340b86a.
Explanation
0.857 moles. This answer is anchored to The mole and the Avogadro constant. is correct because it supports the objective: Apply the mole to electrons, atoms, molecules, ions, formula units and equations.. 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
Misunderstanding the Mole Concept
Students often confuse the mole with the mass of a substance, thinking that the mole is a measure of weight rather than a measure of quantity.
To clarify, remember that the mole is a unit that measures the amount of substance. Use the formula: n = m / Mr, where n is the number of moles, m is the mass in grams, and Mr is the relative formula mass. For example, if you have 18 grams of water (H₂O), calculate the moles as follows: n = 18 g / 18 g/mol = 1 mol. Thus, the answer is 1 mol.
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