Question

What is the mass of 7.0 L of hydrogen gas?

Answer 1

firstly find the no. of moles i.e

n=given volume ÷volume at stp

n=7÷22.4

now no.of moles =guven mass ÷molecular mass

i.e 7÷22.4=m÷2

now you just have to calculations

hope it was useful