Question

Some spherical balloons each of volume 2 L are to be filled with hydrogen gas at one atm and ${27}^{\circ }\text{C}$ from a cylinder of volume 4 L. The pressure of the $H_2$ gas inside the cylinder is 20 atm at ${27}^{\circ }\text{C}$. Find the number of balloons which can be filled using this cylinder. Assume that the temperature of the cylinder is ${27}^{\circ }\text{C}$.

• A. 15
• B. 35
• C. 38
• D. 25

Answer 1

The correct option is C 38

Number of moles of gas taken initially $=\frac{20\times 4}{R\times 300}=3.248$
Number of moles of gas left in cylinder $=\frac{1\times 4}{R\times 300}=0.162$
Number of moles of gas to be filled in the balloons $=3.25-0.162=3.086$

Let's say we have ${}^{\prime }{n}^{\prime }$ balloons that we can fill.
Number of moles of gas that can be filled in 1 balloon $=\frac{1\times 2}{0.082\times 300}=0.081mol$
$\therefore 0.081\times n=3.086$
$n=38$ balloons