Question

The gas constant R represents work done:
A) Per molecule
B) Per degree absolute
C) Per Kelvin per mole
D) Per mole

Answer 1

Hint: The gas constant R is the proportionality constant for the ideal gas equation and its S.I. unit is given on the basis of the values derived for this equation. The answer to your question lies in this fact.

Complete answer:
In the classes of physical chemistry, we have studied about the ideal gas equation and also have come across the concepts of deriving the equation and also its modification.
Now, we shall first see what the gas constant is and then the S.I. units which will lead us to the required answer.
- The gas constant of the ideal gas equation is also called a molar gas constant, ideal gas constant and also universal gas constant.
- This gas constant is defined as the Avogadro gas constant and multiplied by the Boltzmann constant and this is given as,
\[R={{N}_{A}}k\]
Thus proportionality constant is used in physics that relates energy scale to temperature scale when a mole of the particles at particular temperature is considered.
Therefore, substituting the values in the above equation we have,
\[R=6.023\times {{10}^{23}}\times 1.38064J/K\]
\[R=8.314J/mol-K\]
Here the Avogadro number is the number of one mole of species and hence represented and per mole.

Therefore, the correct answer is option C) Per Kelvin per mole.

Note: The S.I. the unit of the gas constant can also be converted into the desired units just by the replacement of the desired value we need and by converting it into the desired units. This gas constant is expressed in various units like L- atm/mol, Pa/ mol-K and so on.