Limiting Reactant Walk Through Needed

[Liliana Teitell]

I've looked up a lot of different ways to solve limiting reactant problems and I still seem to struggle. I was wondering if anyone could explain it in simpler terms or do a walk through of an example?
I understand that we start with balancing the chemical equation to find the correct ratios. Then we calculate the molar mass, but I'm not sure whether it's for the reactants or the products or both. (reactants is the left side of the equation and products is the right side, right?) And then I'm not sure how to continue. I think I am struggling because I do not understand the math conceptually.

[Michael_Kelly_2L]

This is how I would determine the limiting reactant:

1. Balance the chemical equation, the coefficients (number before the element or compound) are really important because that gives us the ratios which is what you mainly use when doing the math.

2. Convert the mass of each REACTANT (usually given) into mol by using their molar masses

3. Choose one of the reactants and use the stoichiometric ratio (mol ratio) to find how much of the 2nd reactant you would need for a complete reaction.

4. If the actual amount of 2nd reactant is greater than how much you need (the amount you found in step 3), the 2nd reactant is in excess (meaning the 1st one is the limiting reactant). If the actual amount of 2nd reactant is less than how much you need, then the 2nd reactant is the limiting reactant)

4. (Alternative method, probably easier) Calculate the amount of product you can make with each amount of reactant you have using mol ratios. Whichever one produces less is the limiting reactant.

Also yes reactants are on the left and whichever one is limiting dictates how much product you can have.

This guideline usually works best for me. Also the textbook fundamentals section M walks through it in a way that helped me. Hope this helps :)