One way to refine iron from iron ore is to heat the ore with hydrogen gas at high temperatures. which change increases the amount of iron produced in the equation

The correct answer is increase in temperature.

Explanation:

During heating of the iron ore with the hydrogen gas at high temperature, the production of water and element iron takes place. High temperature is one of the essential condition for this chemical reaction to take place.  

The more the temperature is, the more will be the amount of the production of iron, this is due to the presence of high temperature, which is one of the mediating force for the production of iron. Therefore, an increase in temperature will produce a greater amount of iron.  

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.