Mass of 1 mL of `H_(2)` gas at STP is same as the mass of `9.86xx10^(17)` atoms of iron. Find the atomic mass of iron.

Explanation

At STP, mass of 22400 mL `H_(2)` gas=2g
`therefore` At STP, mass of 1 mL `H_(2)` gas `=(2)/(22400)=(1)/(11200)g`
At STP, mass of 1 mL `H_(2)=`mass of `9.68xx10^(17)` no. of Fe atoms.
`therefore`mass of `9.68xx10^(17)` number of Fe-atoms`=(1)/(11200)g`
or, mass of `6.022xx10^(23)` number of Fe-atoms
`=(6.022xx10^(23))/(9.68xx10^(17)xx11200)=55.55g`
`therefore` Atomic mass of iron is 55.55.