Water is the change in entropy when 2.5 mole of water is heated from 27° C to 87° C? Assume that the heat capacity is constant.

$\left({\mathrm{C}}_{\text{p.m }}\left({\mathrm{H}}_2\mathrm{O}\right)=4.2\mathrm{J}/\mathrm{g}-\mathrm{K},\ln \left(1.2\right)=0.18\right)$

$\text{ Solution }\to \eta =2.5\text{ mole }$

$T_1={27}^{\circ }C=300 K$

$T_2={87}^{\circ }C=360K$

$C_{\mathit{p}\mathit{m}}\left(n_e\right)=4.2 J/g-K$

$t_2/t_1=360/300=0.18$

$\mathrm{\Delta }s=n\mathrm{Cptm}\left(\frac{T_2}{t_1}\right)$

$Hence,C_p=molarmars\mathit{ }\times c{p}_m$

$=18\times 4.2$

$\mathrm{\Delta }S=2.5\times 4.2\times 18\times \ln \left(0.18\right)=34.025\mathrm{J}/\mathrm{K}$