Burning magnesium gives us magnesium oxide. this is an example of a reaction. is the common element involved with all chemical reactions of this kind. blank 1. combustion. decomposition. replacement. synthesis. blank 2. carbon. hydrogen. magnesium. oxygen.

its {Combustion and Oxygen}

Explanation: combustion means to burn something and as we all know you need oxygen for anything to burn or catch fire

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.