# If four moles of a gas of 5.4 atmospheres have a volume of 120 liters, what is the temperature?

Jun 10, 2016

$T = \frac{P V}{n R}$, i.e. the Ideal Gas equation, and we have all the necessary parameters. We get an answer in degrees Kelvin not Centigrade.
Chemists generally use the gas constant $R$, where $R = 0.0821 \cdot L \cdot a t m \cdot {K}^{-} 1 m o {l}^{-} 1$ (why? because chemists typically use litre volumes, and 1 atmosphere is easy to measure by means of a mercury column).
$T$ $=$ $\frac{5.4 \cdot \cancel{a t m} \times 120 \cdot \cancel{L}}{4 \cdot \cancel{m o l} \times 0.0821 \cdot \cancel{L} \cdot \cancel{a t m} \cdot {K}^{-} 1 \cancel{m o {l}^{-} 1}}$ $=$ (????)/(K^-1) $=$ ??K
So the answer, whatever it is, is in degrees $K \text{, absolute temperature}$ as required. Remember that $\text{degrees Kelvin, K}$ $=$ ""^@C+273.15.