gram calorie
Học thuậtThân thiện
Definition
- Noun:
- A unit of heat energy: A gram calorie is a specific, small unit of heat. It is defined as the precise amount of heat energy needed to increase the temperature of one gram of water by one degree Celsius (centigrade) at a standard atmospheric pressure of one atmosphere.
Usage
- The gram calorie is primarily used in scientific contexts, especially in chemistry, physics, and engineering, to measure small quantities of heat energy.
- It is often used to specify the energy required for or released by chemical reactions or physical processes on a small scale.
- Important Note: In nutrition and food science, the common dietary "Calorie" (capital C) is actually a kilocalorie, which is equal to 1000 gram calories.
Examples
- Noun:
- The reaction released approximately 15 gram calories of heat.
- One gram calorie is equivalent to approximately 4.184 joules, the SI unit of energy.
Advanced Usage
- "small calorie": This is a common synonym for gram calorie, used to distinguish it from the large dietary Calorie (kilocalorie).
- The specific heat capacity of the substance was measured in small calories per gram per degree.
Variants and Related Words
- calorie (small c): Often used interchangeably with gram calorie, though it can sometimes cause confusion with the kilocalorie.
- kilocalorie (kcal) / Calorie (capital C): A unit equal to 1000 gram calories, used for food energy.
- joule (J): The modern SI unit of energy; 1 gram calorie ≈ 4.184 joules.
Synonyms
- small calorie
- calorie (when context is explicitly scientific and small-scale)
Notes on Meaning
- The gram calorie is a metric unit tied to the properties of water. Its definition depends on the starting temperature of the water, as the heat required varies slightly. It is typically defined for a temperature change from 14.5°C to 15.5°C.
- It is a legacy unit largely superseded by the joule in the International System of Units (SI), but it remains useful in specific fields like chemistry.
Noun
- unit of heat defined as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree centigrade at atmospheric pressure