This is the last stage and I don't want to screw this up! :(
Basically, you have to decide if these are reactants or products.

This passage describes a chemical reaction. Read the passage. Then, follow the instructions below.
Buttermilk is a dairy product that contains lactic acid (C3H6O3). The lactic acid makes buttermilk a useful ingredient in pancakes. When buttermilk is added to pancake batter, lactic acid combines with baking soda (NaHCO3) to make carbon dioxide gas (CO2). This gas forms bubbles in the batter, causing the pancakes to rise and become fluffy as they cook.