Question

Calculate the change in entropy when two gram atoms of aluminium is heated from $25^°C$ to $600^°C$. The atomic heat capacity of aluminium is given by $C_p = 5.006 + 0.0026 \,T\, cal/deg$.

• A. $23.75 \,cal/deg$
• B. $6.8 \,eu$
• C. $13.75 \,eu$
• D. $10 \,eu$

Answer 1

Answer: (C)

The process takes place at constant pressure. Hence, $ΔQ = C_p ΔT$
and $\Delta S=\int^{T_{2}}_{T_1} \frac{nC_{p}\,dT}{T}=2 \int^{873}_{298} \left(\frac{5.006}{T}+0.0026\right)dT$
$=2\left[5.006\,ln \frac{873}{298}+0.0026\left(873-298\right)\right]$
$=2\left[5.381+1.495\right]=13.75\,cal/deg$ or $13.75\, eu$