Question:
Calculate the number of $\mathrm{kJ}$ of heat necessary to raise the temperature of $60.0 \mathrm{~g}$ of aluminium from $35^{\circ} \mathrm{C}$ to $55^{\circ} \mathrm{C}$. $\mathrm{Molar}$ heat capacity of $\mathrm{Al}$ is $24 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$.
Solution:
From the expression of heat (q),
$q=m . c \cdot \Delta T$
Where,
c = molar heat capacity
m = mass of substance
$\Delta T=$ change in temperature
Substituting the values in the expression of q:
$q=\left(\frac{60}{27} \mathrm{~mol}\right)\left(24 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)(20 \mathrm{~K})$
q = 1066.7 J
q = 1.07 kJ
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