Question

How many moles of helium gas are in 30.0L sample of He, if density of helium gas is 0.016 g/ml

Answer 1

Volume of the sample, V = 30.0 L

= 30000 ml

The density of the gas, D = 0.016 g/ml

Mass of helium in the sample,

$W = (D×V)$

$= (0.016 g/ml) ×30000 ml$

$=480 g$

Molar mass of helium, M = 4 g/mol

So, number of moles of, helium

n = (Mass of helium in the sample/Molar mass of helium)

= W/M mole

= (480/4) mole

= 120 mole

Hence, there are 120 moles of helium gas are in 30.0L sample of He.