Question

How many $kJ$ of heat is necessary to raise the temperature of $60.0\, g$ of aluminium from $35^{\circ}C$ to $55^{\circ}C$ ?
Molar heat capacity of $Al$ is $24 \,J \,mol^{-1}\,K^{-1}$

• A. $4.07 \,KJ$
• B. $1.07\,KJ$
• C. $3\,K$
• D. $7\,KJ$

Answer 1

Answer: (B)

Mass of $Al = 60 \,g$
Rise in temperature $\Delta\,T=55^{\circ}-35^{\circ}=20^{\circ}C$
Molar heat capacity of $Al=24\,J\,mol^{-}\,K^{-1}$
Specific heat capacity of $Al =\frac{24}{27}J\,g^{-1}\,K^{-1}$
$\therefore $ Energy required $=m \times c \times \Delta\,T$
$60 \times \frac{24}{27} \times 20 = \frac{28800}{27}=1066.67\,J$
$=1.067\,kJ$
or $1.07\,kJ$