Question

What are the units used for the ideal gas law?

Answer 1

The gas laws comprise of the five primary laws namely (i) Charles' Law, (ii) Boyle's Law, (iii) Avogadro's Law, (iv) Gay-Lussac Law and (v) Combined Gas Law. These five gas laws invented the relationship between temperature, pressure, volume and the amount of gas.

Complete step by step answer:
The ideal gas equation refers to the equation of a state of hypothetical ideal gas and is expressed as$PV = nRT$where $P$ is pressure, $V$ is volume, $n$ is amount of substance, $R$ is ideal gas constant and $T$ is temperature.
Let us now discuss the unit for each of these terms used in ideal gas equation one by one:
$P$- The most common units to express pressure include $atm,{\text{ }}mm{\text{ }}Hg,{\text{ }}torr,{\text{ }}Pa,{\text{ }}kPa,{\text{ }}bar$
$V$- The most common units to express volume include $L,{\text{ }}{m^3},{\text{ }}c{m^3},{\text{ }}d{m^3}$
$n$- It is actually the number of moles, thus units are $mol$
$T$- The most common units to express temperature include $^oC,{\text{ }}K{,^o}F\;$
$R$- The ideal gas constant can be actually expressed in multiple units, depending upon what it has been used for $P$,$V$ and $T$. The possible values as well as units of $R$ are listed below. $R$ can be expressed as follows:
$R = \dfrac{{PV}}{{nT}}$
The most widely employed expression for $R$ is when $V$ is given in litres ($L$),$P$ is given in atmosphere ($atm$), and $T$ is given in Kelvin ($K$) so $R$ can be expressed as:
$R = 0.0821\dfrac{{L.atm}}{{mol.K}}$
The other widely employed expression for $R$ is when $V$ is given in litres (${m^3}$),$P$ is given in atmosphere ($Pa$) which results into Joules ($J$) when multiplied and $T$ is given in Kelvin ($K$) so $R$ can be expressed as:
$R = 8.314\dfrac{J}{{mol.K}}$

Note: You must always make sure regarding the units being employed for $R$ that must match the units of $P$,$V$,$n$ and $T$. Keep in mind that real gases are non-ideal which do not follow the ideal gas law exactly. For real gases, two changes have been incorporated like (i) a constant has been added to the pressure (P) and (ii) a different constant has been subtracted from the volume (V). Thus, the new equation for real gas law is: $(P + a{n^2}) \times (V - nb) = nRT$.