The concept of determining which reactant is limiting and which is in excess is akin to determining the number of sandwiches that can be made from a set number of ingredients. Assuming that a cheese sandwich consists of 2 slices of bread and 3 slices of cheese, determine the number of whole cheese sandwiches that can be prepared from 32 slices of bread and 39 slices of cheese.

When there are specific proportions of reactants to complete a process or a product, we can determine, given a set amount of each reactant, which of them is in excess and which of them is limiting.

We need 2 slices of bread and 3 slices of cheese to make a cheese sandwich and we have 32 slices of bread and 39 slices of cheese.

Suppose we use up all the slices of bread to make 32/2= 16 whole sandwiches. 16 sandwiches need 16*3=48 slices of cheese but we only have 39 slices of cheese available. Thus cheese is limiting.

Now we know bread will be in excess, we calculate the number of sandwiches to be made with 39 slices of cheese as 39/3=13.

Those 13 sandwiches will require 13*2=26 slices of bread. Thus, there will be 32-26=6 unused slices of bread.

Answer: 13 sandwiches can be prepared and 6 slices of bread will be leftover