Question

A chemist carefully measures the amount of heat needed to raise the temperature of a 277.0 mg sample of a pure substance from 3.0 °C to 22.0 °C. The
experiment shows that 12.8 J of heat are needed. What can the chemist report for the specific heat capacity of the substance? Be sure your answer has thecorrect number of significant digits.

Answer 1

Use the formula to calculate heat.

$q=m\cdot c\cdot\Delta T$

Where m = 277.0 mg = 0.277g, the variation of the temperatures is from 3.0 °C to 22.0 °C, and q = 12.8 J.

$\begin{gathered} 12.8J=0.277g\cdot c\cdot(22\degree C-3\degree C) \\ 12.8J=0.277g\cdot c\cdot(19\degree C) \\ c=\frac{12.8J}{5.263g\cdot\degree C} \\ c=2.43\cdot(\frac{J}{g\cdot\degree C}) \end{gathered}$

Therefore, the specific heat capacity is 2.43 J/g°C.