Question

A chemist carefully measures the amount of heat needed to raise the temperature of a 306.0 g sample of a pure substance from 1.5°C to 16.4°C. The expert shows that the 634. J of heat are needed. What can the chemist report for the specific heat capacity of the substance? Be sure your answer has the correct number of significant digits

Answer 1

The formula to find the specific heat capacity is

`Q=m\cdot c\cdot\Delta T`

Where Q is the heat, c is the specific heat capacity, m is the mass, and T represents the variation of the temperature. Use the given magnitudes to find c.

`\begin{gathered} 634J=306g\cdot c\cdot(16.4\degree C-1.5\degree C) \\ 634J=306g\cdot c\cdot14.9\degree C \\ c=(634J)/(306g\cdot14.9\degree C) \end{gathered}`

But, we need to express 14.9°C in Kelvin, just add 273.15.

`\begin{gathered} c=(634J)/(306g\cdot288.05K) \\ c=0.00719J\cdot g^(-1)\cdot K^(-1) \end{gathered}`

Therefore, the chemist can report a heat capacity of 0.00719.