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Which of the following has the least mass?

1. 0.2 mol of hydrogen gas
2. 6.023 × 10²² molecules of nitrogen
3. 0.1 g of silver
4. 0.1 mol of oxygen gas

Correct answer: 0.1 g of silver

Solution

0.2 mol H2 = 0.4 g; 6.023e22 N2 = 0.1 mol = 2.8 g; 0.1 g Ag = 0.1 g; 0.1 mol O2 = 3.2 g. Least is 0.1 g of silver, not the hydrogen.

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