Question

Which amount has the greatest mass?

Responses

1 mole of sodium

1 mole of sodium

1 mole of chlorine

1 mole of chlorine

1 mole of uranium

1 mole of uranium

1 mole of oxygen

Answer 1

1 mole of uranium.

Reason: 1 mole of any substance has a mass equal to its molar mass in grams. Approximate molar masses:
- Na ≈ 23 g/mol
- Cl ≈ 35.5 g/mol (Cl2 would be ≈ 71 g/mol)
- O ≈ 16 g/mol
- U ≈ 238 g/mol

Uranium's molar mass (~238 g/mol) is the largest, so 1 mole of uranium has the greatest mass.