Chapter 8, Problem 31QAP

A student is asked to calculate the amount of heat involved in changing 10.0 g of liquid bromine at room temperature (22.5°C) to vapor at 59.0°C.To do this, one must use Tables 8.1 and 8.2 for information on the specific heat, boiling point, and heat of vaporization of bromine. In addition, the following step-wise process must be followed.

(a) Calculate ΔH for: ${\text{Br}}_2\left(l,22.5°\text{C}\right)\to {\text{Br}}_2\left(l,59.0°\text{C}\right)$

(b) Calculate ΔH for: ${\text{Br}}_2\left(l,59.0°\text{C}\right)\to {\text{Br}}_2\left(g,59.0°\text{C}\right)$

(c) Using Hess's law, calculate ΔH for: ${\text{Br}}_2\left(l,22.5°\text{C}\right)\to {\text{Br}}_2\left(g,59.0°\text{C}\right)$