Calculate the kilocalories for each of the following:

Question

A. One cup of popcorn that produces 111 kJ when burned in a calorimeter.

q = ______ kcal

B. A sample of butter that produces 31.9 kJ when burned in a calorimeter.

q = ________ kcal

Answer 1

1 calorie = 4.184 J

1 kilocalorie = 1 Calorie* = 4184 J

(111 KJ)(1000 J/1 KJ) = 111,000 J

(111,000 J)(1 Calorie/4184 J) = 26.5 kJ

*the capitol C in the word “Calorie” denotes “kilo.” If the c in “calorie” is lowercase, then it is not kilo.

use this same method for 31.9 kJ