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.

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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. 0.85 mol
B. 1.00 mol
C. 1.25 mol
D. 1.50 mol

Answer

0.85 mol

Explanation

The number of moles is calculated using the formula: moles = mass / Mr. Here, moles = 50 g / 58.5 g/mol = 0.85 mol.

Common mistake

Confusing moles with mass

Students often confuse the concept of moles with mass, thinking that mass is the same as the amount of substance.

Remember that moles measure the amount of substance, while mass is measured in grams. Use the relationship between mass and moles to clarify this distinction.

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