1. Limiting Reactants

2. How many pancakes can you make?
If you don’t have enough flour to make a full batch of pancakes you can cut down the recipe to make as many pancakes as you can until you run out of flour. The other ingredients will be left over.

3. How much sodium chloride can you make? 2 Na + Cl2  2 NaCl
The same thing can happen in chemical reactions. If you run out of one of the reactants in a chemical reaction, it will limit the amount of product that can be formed. The reactant you run out of first is called the limiting reactant (sometimes called the limiting reagent).

4. 2 Na + Cl2  2 NaCl 46 g 35.5 g i 2 moles 0.5 moles 0 moles c -1 mole
Change back to grams to find the mass of sodium chloride produced and the mass of Na remaining.
23 grams
0 grams
58.5 grams

5. Percentage Yield
Let’s suppose that we ran the reaction for the production of sodium chloride and only obtained grams instead of 58.5 g. We could then calculate the percentage yield as the actual mass divided by the theoretical (calculated) mass times 100%.
Percentage yield = actual yield/theoretical yield x 100
= 49.0 / 58.5 x 100 = 83.8%
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