Answer to Question #169211 in General Chemistry for Obianuju Onyenaekwuru

Question

How many moles of an ideal gas at a temperature of -13 degree and a pressure of 2 atm will occupy a volume of 21.32 dm³ use R=8.31 Jmol^-1 K^-1

Answer 1

To determine the number of moles, the use of the ideal gas low is required:

$pV=nRT$

where $p$ is a pressure (Pa), $V$ is a volume ($m^3$), $n$ is a number of moles, $R$ is a universal gas constant ($J/K\times mol$) and $T$ is a temperature (K).

From this law, the number of moles computes in the following way:

$n=\frac{RT}{pV}$

Taking into account the correct units, $n$ equals to:

$n=\frac{8.31 J/K\times mol\cdot(273-13)K}{(2\cdot101325)Pa \cdot (21.32\cdot 0.001)m^3}=\frac{2160.6}{4320.5}=0.5 mol$