Summary
Highlights
Energy is defined as the capacity to do work or produce heat, existing as potential and kinetic energy. Potential energy depends on the object's composition or position and is influenced by atomic type, bond number, and atomic arrangement. Kinetic energy results from an object's motion, directly related to its random movement and temperature; higher temperatures lead to increased kinetic energy, as seen with boiling water.
The law of conservation of energy states that energy can transform from one form to another but is neither created nor destroyed, also known as the first law of thermodynamics. Chemical potential energy is stored within the chemical bonds of a substance.
Heat (symbolized as Q) is energy transferred from a warmer to a cooler object. For example, a hot cup transfers heat to cold hands until equilibrium is reached. The amount of heat lost by the warmer object equals the heat gained by the cooler one. A calorie (cal) is the heat needed to raise 1 gram of pure water by 1 degree Celsius. Nutritional calories (Cal or kcal) are 1000 times larger than regular calories. The standard unit for energy in the International System of Units (SI) is the Joule (J). One calorie equals 4.184 Joules.
Converting between calories and Joules is crucial. To convert calories to Joules, multiply by 4.184. To convert Joules to calories, divide by 4.184. For example, 142 nutritional calories (Cal) convert to 142,000 regular calories (cal). If 86.5 kilojoules (kJ) of heat are released, this converts to approximately 20.673 kilocalories (kcal), which equals 20.673 nutritional calories (Cal).
Specific heat is the amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius. Each substance has a unique specific heat due to its distinct molecular structure. The formula to calculate heat (Q) absorbed or released is Q = m * c * ΔT, where m is mass, c is specific heat capacity, and ΔT is the change in temperature. The specific heat unit is J/(g·°C). This formula can be rearranged to find specific heat or any other variable.