Which variable represents the number of moles in the equation C_p − C_V = nR?

In the equation ( C_p - C_V = nR ), the variable that represents the number of moles is ( n ). This equation relates the heat capacities at constant pressure (( C_p )) and constant volume (( C_V )) of a substance, with ( R ) being the ideal gas constant.

The term ( n ) is crucial in this context since it quantifies the amount of substance involved in the process. When considering heat capacity, it is important to understand that these capacities depend on how much of the substance is present; that is, they are properties per mole of the substance. Thus, ( n ), representing the number of moles, indicates how the heat capacities will scale with the quantity of substance being measured.

In essence, this equation highlights the relationship between these thermodynamic quantities and how they vary with the amount of substance, reinforcing the importance of the number of moles in thermochemical calculations.