# How To Solve Mass To Mass Stoichiometry Problems In the real world, no reaction ever goes to completion.

Sadly, for this example, we have to move on from our beloved methane combustion equation ( Pretty intimidating if you don’t know what to do, right? In this case, we can see that the p H passes through the equivalence point (where the acid and the base cancel each other out and the p H is of oxalic acid. You’ll notice that the common thread running through all of them is the expected value.

Essentially, if you understand expected value really well, you should be able to figure out most of the rest.

He was appointed chemist at the royal porcelain factory in Berlin.

Along with the law of definite proportions (stoichiometry) he also developed titrations.

Percent yield is a way of quantifying the difference between the theoretical yield (the expected value) and the experimental yield.

Using the same reaction yet again, let’s say that you were given a problem like this. In fact, there is an easier way to do this calculation.Let’s say that we have this equation, which is the combustion of methane. Then I do the same on the right side: one carbon, two hydrogens, and three oxygens. The only way to get that four hydrogens is to double the amount of …and this equation is now balanced.You’ve probably learned much of this even in a non-AP chemistry class, so bear with me; it’ll get more advanced.First, let’s talk about the basic concepts of stoichiometry.First of all, we have to start with a balanced reaction. I add up the number of atoms of each element on the left side: one carbon, four hydrogens, and two oxygens. First, we look at the left side and see that we need four hydrogens.However, on a multiple choice stoichiometry problem, you may want to use that little trick.Why can’t we use that trick for gram-based stoichiometry problems?The AACT high school classroom resource library has everything you need to put together a unit plan for your classroom: lessons, activities, labs, projects, videos, simulations, and animations.We constructed a unit plan using AACT resources that is designed to teach the concepts of stoichiometry and limiting reactants to your students.The standard practice to eliminate this problem is to simply carry out both calculations as expected value calculations.So, let’s pretend that we’re calculating the expected value of , so oxygen is the limiting reactant here because its expected value in the reaction was less.