Question

What are the units used for the ideal gas law?

Answer 1

Hint: 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: $(P + a{n^2}) \times (V - nb) = nRT$.