When iron metal reacts with sulfuric acid, it produces iron (iii) sulfate and hydrogen gas. balance the equation: fe + h2so4 ? fe2(so4)3 + h2. explain why it is necessary to balance chemical equations and why coefficients can be added to an equation, but subscripts cannot be changed.

2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2.

Balancing chemical equations is essential because it explains how much of a certain chemical is needed for a reaction to occur. Coeffecients can be added because it's just showing how many molecules will be reacted or produced in a given equation. Subscripts can't be changed because that's messing with the type of chemical directly--not the amount of chemical. If you change subscripts, that would mean you're changing the properties of the substance at hand. For example, C2H5OH can get you drunk, while CH3OH can kill you with only a few mililiters. They have the same elements involved--it just matters how many of those elements you have in the equation.