Calorie

Definition

A calorie is a unit of energy defined as the amount of heat required to raise the temperature of 1 gram of water by 1 degree Celsius. In scientific contexts, it is often replaced by the joule, where 1 calorie equals approximately 4.184 joules.

5 Must Know Facts For Your Next Test

1. A calorie is a unit used to measure energy in thermodynamics and heat transfer processes.
2. One calorie is equivalent to approximately 4.184 joules.
3. Calories are commonly used in calorimetry experiments to determine the specific heat capacities of substances.
4. The dietary Calorie (with an uppercase C) is actually a kilocalorie (1000 calories).
5. In equations, calories can be converted to joules using the relation: $Q = mc\Delta T$ where $Q$ is in calories or joules.

Review Questions

• How many joules are equivalent to one calorie?
• What does a dietary Calorie represent in terms of regular calories?
• Why might scientists prefer using joules over calories in thermodynamic calculations?

Related terms

Joule:

A derived unit of energy in the International System of Units (SI), equal to the energy transferred when applying a force of one newton over a distance of one meter.

Specific Heat Capacity: The amount of heat required to change the temperature of one gram of a substance by one degree Celsius.

Calorimetry:

The science or practice of measuring quantities of heat transferred during chemical reactions or physical changes.