# A sample of hydrogen gas (H_2) has a volume of 8.56 L at a temperature of 0"^oC and a pressure of 1.5 atm. How do you calculate the moles of H_2 molecules present in this gas sample?

We use the ideal gas equation.......$P V = n R T$, to get $n \cong 0.6 \cdot m o l$
$n = \frac{P V}{R T}$ $=$ $\frac{1.5 \cdot a t m \times 8.56 \cdot L}{0.0821 \cdot L \cdot a t m \cdot m o {l}^{-} 1 \cdot {K}^{-} 1 \times 273 \cdot K}$