What is enthalpy?
Enthalpy (given the symbol H) is a measure of how much heat energy can be released by a chemical. ΔH is defined as the amount of heat energy released or taken in when two chemicals react. If ΔH is negative it means that the reaction is exothermic and will give out heat as it progresses and will feel hot.
If ΔH is positive then the reaction is endothermic and will therefore absorb heat as it progresses, and will feel cold.
CM
Related Chemistry A Level answers
All answers ▸What factors influence the reaction rate?
i)Give the Correct full electronic configuration for the Mg2+ ion, ii) and state why it is easier to form the 2+ state for Mg than Ben
Why does ionisation energy decrease down group 2?
Imagine a reaction A for which the values of ΔH and ΔS are both negative. It is known that the absolute value of ΔS is 3 times smaller than the absolute value of ΔH. For what values of T does reaction A occur spontaneously?