Question

A 20.6-L tank contains 0.206 kg of helium at 16.4°C. The molar mass of helium is 4.00 g/mol.

(a) How many moles of helium are in the tank?
  mol

(b) What is the pressure in the tank, in pascals and in atmospheres?

Pa ?

atm?

Answer 1

a) Number of moles $n=\frac{206}{4}=51.5moles$ . $\implies P=\frac{51.5\times8.31\times289.4}{20.6\times10^{-3}}$

b) $PV=nRT$

$\implies P=\frac{nRT}{V}$

$\implies P=\frac{51.5\times8.31\times289.4}{20.6\times10^{-3}}$ , All in SI units

$\implies P=6012285 Pa$ =59.33atm