Question

A balloon filled with helium rises to a certain height at which it gets fully inflated to a volume of $1\times {10}^5$ liters. If at this altitude temperature and atmospheric pressure is $268$K and $2\times {10}^{-3}$ atm respectively, what weight if helium will be required to fully inflate the balloon?

Answer 1

Using $PV=nRT$ formula

$2\times {10}^{-3}\times {10}^5=n\times 8.314\times 268$

$n=0.1$

weight$=n\times$ gram molecular weight of He

weight$=0.1\times 4=0.4$ grams.