Answer
$R$ is specific for every gas. $R_{u}$ its the same for all gases.
$R=\frac{R_{u}}{M}$
Work Step by Step
$R$ is the specific gas constant and its different for every gas. $R_{u}$ is the universal gas constant and its the same for all gases.
$R=\frac{R_{u}}{M}$ where $M$ is the molar mass of the gas.
