Question

Can heat be added to solid,liquid,gas without changing the temperature? Explain

Answer 1

Answer:

Any change of state that needs latent heat, gives rise to a requirement for heat input at a constant temperature during the phase change. Eg, continuous boiling of water in a kettle maintains a constant temperature, despite the input of heat to convert the liquid to water vapour at 100C. The heat input is largely that required to supply the latent heat of vaporisation amounting to 540 cal/gm of conversion. A similar constant temperature during phase change applies during freezing of water which requires 80 cal/gm at 0C.

A further example is heating an azeotropic mixture of, say, an alcohol and water. This is known as a ‘constant-boiling’ mixture because the composition of the liquid phase is the same as that of the gas (distillate) phase. Either side of the bp of the azeotrope the liquid and gas phases have different compositions.

Answer 2

Answer:

Heat is added to solid without changing the temperature because the heat is used in breaking the molecular force of attraction .