If a gas has $f$ degrees of freedom,what is the ratio ${C_p}/{C_v}$?

$5$ moles of oxygen is heated at constant volume from $10^{\circ}C$ to $20^{\circ}C$. The change in the internal energy of the gas is (given $C_p = 8 \text{ cal/mole } ^{\circ}C$ and $R = 2 \text{ cal/mole } ^{\circ}C$ approximately).

$50 \, cal$ of heat is required to raise the temperature of $1 \, mol$ of an ideal gas from $20^{\circ} C$ to $25^{\circ} C$,while the pressure of the gas is kept constant. The amount of heat required to raise the temperature of the same gas through the same temperature range at constant volume is ........ $cal$ $(R = 2 \, cal / mol \cdot K)$.

What is the molar heat capacity of water? ($R$ is the universal gas constant.)

Can we use the degree of freedom to obtain the specific heat capacity of a gas? Explain.

For a rigid diatomic molecule,the universal gas constant $R = n C_P$,where $C_P$ is the molar specific heat at constant pressure and $n$ is a number. Hence,$n$ is equal to