A chemical reaction that absorbs energy from the surroundings, usually in the form of heat, resulting in a decrease in temperature. The enthalpy change (ΔH) for an endothermic reaction is positive.
Exothermic Reaction
A chemical reaction that releases energy to the surroundings, usually in the form of heat, resulting in an increase in temperature. The enthalpy change (ΔH) for an exothermic reaction is negative.
Standard Enthalpy Change of Reaction (ΔHr∘)
The enthalpy change that occurs when a reaction takes place under standard conditions (100 kPa, 298 K) and in its standard state.
Standard Enthalpy Change of Formation (ΔHf∘)
The enthalpy change when one mole of a compound is formed from its elements in their standard states under standard conditions.
Standard Enthalpy Change of Combustion (ΔHc∘)
The enthalpy change when one mole of a substance is completely burned in oxygen under standard conditions.
Specific Heat Capacity (c)
The amount of heat energy required to raise the temperature of one gram of a substance by one degree Celsius. It's used in calculations involving heat transfer in physical and chemical processes.
