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I've noticed in the textbook/course reader when balancing equations to calculate things like enthalpy and entropy sometimes we balance the equations with integers, and other times we will have values that are fractions. When do we know when it is necessary to use integers and when not to, since this does affect our final answer?
Usually, the only time we have really needed to use fractions for balancing equations is if we are calculating the standard enthalpy of formation; that is just so the manipulated equations will look like the final. Besides that, we will balance equations with integers.
I believe that fractions are only used to make calculations easier. For example, the mole ratio of reactants to products may be 2 mol reactant forms 3 mol product (2:3), but the question may ask you about "what happens when 1 mol of reactant...?", therefore, you may want to change the coefficients so that the ratio will be 1:3/2. This isn't necessary though, because you could just use the original mol ratio and divide your final answer (the enthalpy or entropy) by 2 (or whatever value you need to). However, this step is easy to forget, so it can be better to adjust the mol ratio first. It's just a personal preference.
You use fractions when you are calculating things like heat of formation (which is for one mole of whatever you want to form). Whenever you want to calculate one mole of something, everything else becomes a fraction. Otherwise you can use integers.
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