calorie (thermochemical) (cal)
1 calorie (thermochemical) = 4.184 joules
What is calorie (thermochemical)?
The thermochemical calorie is a unit of energy equal to approximately 4.184 joules. It is used in chemistry and physics to express small heat quantities, particularly in thermochemical experiments.
Notes: Non-SI unit
Real-world uses
The thermochemical calorie (4.184 J) is used in chemistry for expressing heats of reaction, specific heat capacities of substances, and calorimetry experiments. It appears in older scientific literature and some chemistry textbooks, particularly in calorimetric calculations.
History
The calorie was first defined by Nicolas Clément in 1824 as the heat needed to raise 1 gram of water by 1°C. The thermochemical calorie (exactly 4.184 J) was later standardized for precise scientific use, distinguishing it from other calorie definitions.
Common mistakes
Confusing the small calorie (cal, 4.184 J) with the large Calorie/kilocalorie (Cal/kcal, 4,184 J) used in food labelling. Also, several slightly different definitions of the calorie exist (thermochemical, 15°C, IT), which differ by fractions of a percent.
When is this conversion used?
Electricity bills use kilowatt-hours while physics calculations use joules. Converting between them is essential for energy audits, comparing appliance efficiency, and understanding power consumption.
How to convert calorie (thermochemical) to joule
To convert calorie (thermochemical) to joule, multiply the value by 4.184.
Conversion formula (from base unit)
x * 4.184
Measurement standards
The joule is the SI derived unit of energy, defined as one kilogram-metre-squared per second-squared (kg·m²/s²). The kilowatt-hour, equal to exactly 3.6 megajoules, is accepted for use with the SI by the BIPM for practical electricity metering.
Did you know?
A single bolt of lightning releases roughly 1 to 5 gigajoules of energy, yet only a small fraction reaches the ground as electrical current. Most of the energy dissipates as light, heat, and the thunder shockwave.
| calories (thermochemical) | joules |
|---|---|
| 0.1 | 0.4184 |
| 0.5 | 2.092 |
| 1 | 4.184 |
| 2 | 8.368 |
| 5 | 20.92 |
| 10 | 41.84 |
| 25 | 104.6 |
| 50 | 209.2 |
| 100 | 418.4 |
| 250 | 1,046 |
| 500 | 2,092 |
| 1,000 | 4,184 |
Common values
| calories (thermochemical) | joules | |
|---|---|---|
| A food calorie (1 kcal) | 1,000 calories (thermochemical) | 4,184 joules |
| A AA battery | 2,237.09369025 calories (thermochemical) | 9,360 joules |
| Boiling a kettle | 100,382.40917782 calories (thermochemical) | 420,000 joules |
| Daily human diet (2000 kcal) | 2,000,000 calories (thermochemical) | 8,368,000 joules |
| 1 gallon of gasoline | 31,491,395.79349904 calories (thermochemical) | 131,760,000 joules |
Full calorie (thermochemical) conversion table
| Unit | Value | Factor |
|---|---|---|
| joule | 1 cal = 4.184 J | × 4.184 |
| kilojoule | 1 cal = 0.004184 kJ | × 0.004184 |
| kilowatt hour | 1 cal = 0.00000116 kWh | × 0.00000116 |
| kilocalorie (dietary) | 1 cal = 0.001 kcal | × 0.001 |
| watt hour | 1 cal = 0.00116222 Wh | × 0.00116222 |
| megajoule | 1 cal = 0.00000418 MJ | × 0.00000418 |
| electronvolt | 1 cal = 2.611447e+19 eV | × 2.611447e+19 |
| British thermal unit | 1 cal = 0.00396567 BTU | × 0.00396567 |
| therm (US) | 1 cal = 3.966614e-08 therm | × 3.966614e-08 |