Question

Convert the following numbers of calories or

kilocalories into joules or kilojoules.
a. 7845 cal
b. 4.55 x 104 cal
C. 62.142 kcal
d. 43,024 cal

Answer 1

• 32.823 kJ
• 190.4 kJ
• 260.00 kJ
• 180.012 kJ

Explanation:

The conversion factor for food energy or thermochemical calorimetry* is ...

1 calorie = 4.184 J

1000 calorie = 4.184 kJ

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a. 7845 cal = 7845·4.184 J = 32,823 J = 32.823 kJ

b. 4.55·10^4 cal = 4.55·10^4·4.184 J = 1.904·10^5 J = 190.4 kJ

c. 62.142 kcal = 62.142·4.184 kJ = 260.00 kJ

d. 43,024 cal = 43,024·4.184 J = 180,012 J = 180.012 kJ

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* The thermochemical calorie is defined in terms of the heat capacity of water. An international calorie of 4.1868 J is defined in terms of energy, without respect to the heat capacity of water.