Chapter U5, Problem 7STP

Interpretation Introduction

Interpretation:

The substance that would require the most energy to increase the temperature from 20°C to 30°C needs to be determined.

Concept introduction:

Due to transfer of energy, the temperature of any substance increases or decreases. The change in temperature for the addition of energy can be calculated with the help of calorimetric equation:

$\begin{array}{l}\text{Q = m × C × ΔT}\\ \text{Here:}\\ \text{Q}\text{}\text{ = heat change }\\ \text{m = mass}\\ \text{C = specific heat }\\ \text{ΔT = change in T}\end{array}$

Answer to Problem 7STP

Option (A) is correct statement.

Explanation of Solution

Reason for correct option:

Specific heat can be defined as the heat that would require to raise the temperature of 1 unit mass by per °C. Thus, the substance with highest specific heat would require the most energy to increase the temperature from 20°C to 30°C as the temperature difference and mass is same for all the given substance.

In the given substances, water has highest specific heat so it would require most energy.

Conclusion

Reasons for incorrect options:

Specific heat is the determining factor for the heat that is required to the temperature of the substances. Methanol, brass and aluminum have lesser specific heat than water.