Chapter U5.9, Problem 5E

Interpretation Introduction

Interpretation: The energy transfer from a burned cereal flake under a beaker containing 25 mL of water needs to be determined.

Concept Introduction: The below formula is used to calculate the energy transfer during a calorimetry procedure.

  $q=m{C}_p\Delta T$

Here, $m$ represents mass of water, $C_p$ and $\Delta T$ represents specific heat and temperature change respectively.

Answer to Problem 5E

Energy transferred to the water is $\text{150}\text{cal}$ .

Explanation of Solution

Calculate energy transfer as follows:

The equation for the heat transfer is

  $q=m{C}_p\Delta T$ .................(1)

Given values are as follows:

1mL of water is equal to 1.0g water, Therefore, the mass of water heated is 25.0g.

  $\begin{array}{l}m=25\text{g}\\ C_p=1.00\text{cal/g}\text{.}°\text{C}\\ \Delta T=6°\text{C}\\ q=?\end{array}$

Substitute above values in equation (1).

  $\begin{array}{c}q=m{C}_p\Delta T\\ =25\text{g}\times 1.00\text{cal/g}\text{.}°\text{C}\times 6°\text{C}\\ \text{=150}\text{cal}\end{array}$

Therefore, energy transferred to the water is $\text{150}\text{cal}$ .

Conclusion

Energy transferred to the water is $\text{150}\text{cal}$ .