Question

80 g of oxygen contains as many atoms as in
A. 10 g of hydrogen
B. 5 g of hydrogen
C. 80 g of hydrogen
D. 1 g of hydrogen

Answer 1

Correct Answer - B
No. of mole of oxygen `=80/16=5` mol
1 mol contains avogadro no. of atom i.e., `6.02xx10^(23)` atoms.
`:.` 5 mol contains `6.02xx10^(23) xx5` atoms
`=30.1xx10^(23)` atoms
Similarly in option (b)
No. of mol of hydrogen `=5/1=5` mol
5 mol of hydrogen contains `30.1xx10^(23)` atoms.