Question

How do you solve thermal equilibrium problems?

Answer 1

Following is a summary of methods involved while solving thermal equilibrium problems:

1) Write a brief description of all the heat involved.

2) Use the equation $\mathrm{\Sigma }\mathrm{Q}=0$ to write the equation in the form of ${\mathrm{Q}}_1+{\mathrm{Q}}_2+{\mathrm{Q}}_3+........=0$

3) Use the $\mathrm{Q}=\mathrm{mc}∆\mathrm{T}$ for each $\mathrm{Q}$ associated with the change in temperature $∆\mathrm{T}$. Express $∆\mathrm{T}$ as ${\mathrm{T}}_{\mathrm{final}}-{\mathrm{T}}_{\mathrm{initial}}$

4) Make use of equation $\mathrm{Q}={\mathrm{mL}}_{\mathrm{f}}$ and $\mathrm{Q}={\mathrm{mL}}_{\mathrm{v}}$ to write an expression for the heat associated with a phase change. If the heat is added to produce a phase change as in the case of melting or vaporising use a plus sign if the heat is removed to create a phase change, then use a minus sign.

5) Now solve the resulting equation for the unknown variable.