Question d2047

May 21, 2017

$\text{1.8 L}$

Explanation:

The first thing that you must do here is to convert the number of molecules of hydrogen to moles by using Avogadro's constant, which tells you that in order to have $1$ mole of hydrogen gas, you need to have $6.022 \cdot {10}^{23}$ molecules of hydrogen.

You can thus say that your sample contains

4.8 * 10^(22) color(red)(cancel(color(black)("molecules H"_2))) * "1 mole H"_2/(6.022 * 10^(23)color(red)(cancel(color(black)("molecules H"_2))))#

$= {\text{0.0797 moles H}}_{2}$

Now, you should know that under STP conditions, which are currently defined as a pressure of $\text{100 kPa}$ and a temperature of ${0}^{\circ} \text{C}$, $1$ mole of any ideal gas occupies $\text{22.7 L}$ $\to$ this is known as the molar volume of a gas at STP.

This implies that your sample will occupy

$0.0797 \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{moles H"_2))) * "22.7 L"/(1color(red)(cancel(color(black)("mole H"_2)))) = color(darkgreen)(ul(color(black)("1.8 L}}}}$

The answer is rounded to two sig figs.