Question

An LPG cylinder weighs $14.8\text{kg}$ when empty. When it is full, it weighs $29\text{kg}$ and after consumption, the weight of the cylinder reduces to $23.2\text{kg}$. Find out the volume of n-butane in cubic metres used up at ${27}^{\circ }\text{C}$ and $1atm$.
[Molecular mass of n-butane = 58 g/mol]

Answer 1

Mass of n-butane gas used $29-23.2=5.8\text{kg}=5800$ g
Number of moles of butane used $=\frac{5800}{58}=100$ mol
Using the ideal gas equation, PV = nRT
T = ${27}^{o}C$ = 300 K, R = 0.0821 atm.L/ (mol.K)
So, $V=\frac{nRT}{P}=\frac{100\times 0.0821\times 300}{1}$
On solving, V$=2463$ L
Since, 1 L = ${10}^{-3}{m}^3$
Volume of the n-butane gas used is V $=2.463{\text{m}}^3$