Ammonia (NH3 (g), Delta. Hf = –45.9 kJ/mol ) reacts with oxygen to produce nitrogen and water (H2 O(g), Delta. Hf = –241.8 kJ/mol) according to the equation below. 4 upper N upper H subscript 3 (g) plus 3 upper O subscript 2 (g) right arrow 2 upper N subscript 2 (g) plus 6 upper H subscript 2 upper O (g). What is the enthalpy of the reaction? Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants.. –3,572.1 kJ –1,267.2 kJ 1,267.2 kJ 3,572.1 kJ

the correct answer is:

a. formation of precipitation

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.

a corroding iron, if that's one of your choices