alleryStart learning →How many joules is one calorie defined to equal?
A1.000 joules
B1000 joules
C0.239 joules
D4.184 joules
Answer & Solution
Correct answer: D. 4.184 joules
1. A calorie was originally the energy needed to raise 1 gram of water by 1 degree Celsius.
2. That quantity depends on pressure and starting temperature, so it was standardised.
3. One calorie is now set to equal exactly 4.184 joules.
4. The joule is the SI unit of heat, work and energy, and 1000 J make 1 kJ.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 5 "Thermochemistry", section 5.1 Energy Basics_
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