The molar heat capacity for an ideal gas at constant pressure is \(20.785\,\mathrm{J\,K^{-1}\,mol^{-1}}\). The change in internal energy is \(5000\,\mathrm{J}\) upon heating it from \(300\,\mathrm{K}\) to \(500\,\mathrm{K}\). The number of moles of the gas at constant volume is \(\_\_\_\_\_\_\). [Nearest Integer] (Given \(R=8.314\,\mathrm{J\,K^{-1}\,mol^{-1}}\))