A block of a certain material is heated to a temperature of $500^{\circ} \mathrm{C}$ and then placed on a large ice block. If 1.455 kg of ice melts, find the mass of the block.

Specific heat of the material is $0.39 \mathrm{Jg}^{-1} \mathrm{C}^{-1}$ and heat of fusion of water is $335 \mathrm{Jg}^{-1}$.

Following graph shows four different processes, adiabatic, isothermal, isobaric and isochoric for an ideal gas, from the same initial state. Study the graph carefully and state which of the following statements is correct?

A vessel of volume $27 \times 10^4 \mathrm{cc}$, contains a mixture of Hydrogen (molar mass $=2 \mathrm{~g} \mathrm{~mol}^{-1}$ ) and oxygen (molar mass $=32 \mathrm{~g} \mathrm{~mol}^{-1}$ ) gas at standard temperature and pressure. If the mass of hydrogen is 16 g , find the mass of oxygen gas contained in the vessel.

Find the mass of oxygen gas with which $1.882 \times 10^{23}$ degrees of freedom are associated at N.T.P. Given: Molar mass of diatomic gas, oxygen is $32 \mathrm{~g} \mathrm{~mol}^{-1}$ and oxygen molecule possess three translational and two rotational degrees of freedom.