Chapter 1, Problem 1.1CP

Real walls are never totally adiabatic. Use your experience to order the following walls in increasing order with respect to their being diathermal: 1-cm-thick concrete, 1-cm-thick vacuum, 1-cm-thick copper, 1-cm-thick cork.

Interpretation Introduction

Interpretation:The increasing order of the given walls with respect to their diathermal property needs to be determined.

Concept Introduction: Thermodynamics is the branch of chemistry that deals with heat exchange between system and surroundings. The thermodynamic process can be classified into two types; isothermal and adiabatic process. An isothermal process occurs at a constant temperature between the system and surroundings. On the contrary, adiabatic processes do not allow the transfer of heat.

Answer to Problem 1.1CP

  $\text{1-cm-thick vacuum < 1-cm-thick cork <1-cm thick concrete < 1-cm-thick copper}$

Explanation of Solution

Given information:The real walls are never totally adiabatic.

An adiabatic process doesnot allow the transfer of heat through it. A diathermal wall can be defined as the wall separating two thermodynamic systems in which transfer of heat takes place but transfer of matter is not allowed.

Hence the amount of heat transfer will depend on the heat capacity of the diathermal wall. In the given options, the copper wall will be more diathermal as it has the highest heat capacity compared to concrete, cork and vacuum. Whereas vacuum will be least diathermal due to the least heat capacity.

Conclusion

Thus, the increasing order of diathermal capacity is as follows: $\text{1-cm-thick vacuum < 1-cm-thick cork <1-cm thick concrete < 1-cm-thick copper}$