Calculate the number of mole of atom in 8g of oxygen gas (relative atomic mass for oxyegn: 16g/mol)?

Science & Mathematics by Anonymous 2018-06-24 14:02:08

Social Science

2 answers

I got 0.5 mol 8g/(16g/mol) = 0.5 mol but why is the answer 0.25 mol

Anonymous

A molecule of oxygen is O2, not just O. Therefore, the molar mass is 32, not 16. And that's why 8 grams is 1/4 mole, not 1/2 mole.
Anonymous

Molar mass of O atoms = 16 g/mol No. of moles of O atoms = (8 g) / (16 g/mol) = 0.5 mol Molar mass of O₂ = 16 × 2 g/mol = 32 g/mol No. of moles of O₂ molecules = (8 g) / (32 g/mol) = 0.25 mol