Calculating with Q=cmΔt

Get Problem Answer  |  Get New Problem  |  Go Problem Menu

Background

Assuming that all of the heat of the reaction is directed toward changing the temperature of the liquid, then the following equation applies:

Heat = (Specific Heat)(Mass)(Temperature Change) or Q=cmΔT
calories = (calories/grams*Celsius)(grams)(Celsius)

Textbook Discussion: Sections 7.8, 7.9 and 7.10, pages 224-229. See Also: Example VII, VIII, and IX, pages 226, 227, and 228.

Problem

A chemical reaction takes place inside of a metal container that is immersed in 1570 grams of a liquid. The initial temperature of the liquid is 18.6 degrees C. The chemical reaction causes the temperature of the liquid to change. After the chemical reaction, the final temperature of the liquid is 26.8 degrees C. Is the chemical reaction exothermic or endothermic, and how many calories of heat are exchanged as a result of the chemical reaction? The specific heat of the liquid is 0.219 cal/gC. Note: Answer must reflect correct sign and magnitude.