Question

$5g$ of copper was heated from ${20^\circ }C$ to ${80^\circ }C$. How much energy was used to heat the $Cu$? (Specific heat for copper $= \dfrac{{0.38J}}{{g{.^\circ }C}}$).

Answer 1

As we know that the specific heat of a substance is that amount of heat which is required to raise the temperature of unit mass of a substance usually by one degree and it is determined by the ratio of energy to the mass of that substance and the change in temperature.

Complete step-by-step answer:
As we have already discussed that the specific heat is expressed in terms of the heat energy supplied to the substance to raise the temperature, mass of that substance and change in temperature and it is normally expressed as shown below:
$C = \dfrac{{heat\;energy(Q)}}{{mass \times \Delta T}}$
Where, $\Delta T$ is the change in temperature and is determined by the difference of lower and higher temperature.

Thus, when $5g$ of copper was heated and the temperature is changed from ${20^\circ }C$ to ${80^\circ }C$, the specific heat was given as $0.38$ then the amount of energy which would have been used in the reaction would be given as:
$\Rightarrow Q = 5 \times 0.38 \times (80 - {20^\circ }C)$
$\Rightarrow Q = 1.9 \times 60$
$\Rightarrow Q = 114J$

Therefore, from the above calculations we can say that the heat energy required to heat the copper is $114J$.

Additional information: the heat capacity or heat energy is defined as the physical property of a matter which is used as to supply to a given mass of a substance so as to produce a change in temperature by exactly a unit.

Note: Always remember that the specific heat of a substance is a tool which determines the heat capacity of a heated as well as a cooled sample. We use the specific heat to basically raise the temperature of a substance usually by one degree.