Question

what is standard enthalpy of reaction?

Answer 1

it is the enthalpy change that occurs in a system when one mole of matter is transformed by a chemical reaction under standard conditions.

Answer 2

 Standard enthalpy of formation is the change in enthalpy when one mole of a substance, in the standard state of 1 atm of pressure and temperature of it is 298.15 K, is formed from its pure elements under the same conditions. Hope it helps. Also vote it the brainliest answer! :)