How does the calorie compare to the metric unit the joule? How do you calculate a calorie? Is it the same for all types of food?

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Chemistry

Finnegan

1 January, 03:09

How does the calorie compare to the metric unit the joule? How do you calculate a calorie? Is it the same for all types of food?

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Ralph Lewis · Answer 1

Calorie (cal) or small calorie, is the amount of energy needed to heat one gram of water by one degree Celsius.

One small calorie is approximately 4.2 joules.

A calorie is a unit of energy.

For example:

Q = 150000 J; released energy.

Convert Jules in calories:

Q = 150000 J : 4.186 J/calorie.

Q = 35833.73 calorie.

The large calorie or nutritional calorie (symbols: Cal, kcal) is the heat energy needed to raise the temperature of one kilogramof water by one degree Celsius.

A nutritional calorie, or kilocalorie, is equal to 1000 calories.

One large calorie is 4.184 kilojoules: 1 Cal = 4.184 kJ.

For example:

E = 2500 Cal; energy burnt.

E = 2500 Cal · 4.184 kJ/Cal.

E = 10460 kJ.