Question

If all of the chemical potential energy stored in a 100 Calorie snack pack was converted to thermal energy and subsequently absorbed by water, what would be the final temperature of the water? Assume you have a 1.5 mole sample of water initially at 25 degrees C. The specific heat of water is 4.184 J/g degrees C.

Answer 1

A 100 Calorie food snack pack actually is 100,000 "real" calories (the so-called big calorie is a kilocalorie). So,
q = mass x specific heat x (Tfinal-Tinitial).
You need to change 100,000 calories to joules (4.184 Joules = 1 calorie). You need to change 1.5 mole water to grams. Tfinal is the unknown and Tinitial is 25.