Ques 1) In determining and then using the specific heat of any substance:- For solids and liquids, we usually assume that the sample is under constant pressure during the transfer, or at constant volume while the heat is absorbed. Then is it possible that the thermal expansion of the sample can be prevented by applying external pressure ? Ques 2) Why it is that the specific heats under constant pressure and constant volume for any solid or liquid differ usually by no more than a few percent, where as gases have different values for their specific heats under constant pressure and constant volume ? Ques 3) Generally , thermal expansion of gases is greater than that of solids and liquids . But this is true at any temperature (though the thermal expansion coefficient depends slightly on temperature) ? Is it due to the fact that the state of randomness for gas is much higher than that for liquid or gas.