The internal energy change (in J) When 90 g of water undergoes complete evaporation at 100^oC is ____________.

(Given : $$\Delta $$H_vap for water at 373 K = 41 kJ/mol,
R = 8.314 JK^–1 mol^–1)

At constant volume, 4 mol of an ideal gas when heated from 300 K to 500K changes its internal energy by 5000 J. The molar heat capacity at constant volume is _______.

The magnitude of work done by a gas that undergoes a reversible expansion along the path ABC shown in the figure is _______.

The standard heat of formation $$\left( {{\Delta _f}H_{298}^0} \right)$$ of ethane (in kj/mol), if the heat of combustion of ethane, hydrogen and graphite are - 1560, -393.5 and -286 Kj/mol, respectively is :