How many moles are present in 400 g of CaCO3? (Relative formula mass = 100)
Answer and explanation
Correct answer: B. 4 mol
- Step 1: Amount in moles n = mass / molar mass.
- Step 2: n = 400 / 100 = 4 mol.
Answer
4 mol.
Why not the others: '2 mol' divides the mass by twice the molar mass; '0.25 mol' inverts the ratio mass / molar mass; '6 mol' adds two to the correct amount.
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