commercial scuba divers use tanks filled with a mixture of gases known as trimix on very long, deep dives. Trimix is composed of 70 percent nitrogen, 10 percent oxygen, and 20 percent helium. The total pressure of trimix inside a certain tank at the beginning of a dive is 118.4atm.

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.

what is the question here. i think you messed up.