Baking soda is a very important ingredient in kitchen chemistry because when reacted with a weak acid in a cake, carbon dioxide bubbles are produced, causing the batter to rise. In this experiment, the mass of the reactants and products were measured and recorded, as well as relative masses and number of moles. These numbers will help the student to understand the mass and mole relationships. .
In the data table, the mass of the dish and watch glass was recorded as 50.43 grams. The mass of the dish, glass, and 2.38 g of baking soda was 52.81 grams. The mass of the dish, glass, and NaCl residue after the heating of the dish was 51.4 g. This means that after the substance was heated, a chemical reaction took place, and the product, NaCl, was 1.4 grams less than the reactant, NaHCO3. In the calculations table, the mass of the reactant, NaHCO3, was found to be 2.38 g. The number of moles of NaHCO3 reacted was .028 moles. The mass of the product NaCl was 1.41 g. The number of moles of NaCl produced was .028 moles. The experimental mole ratio of NaCl to NaHCO3 was 1:1. The theoretical yield of NaCl was 1.65 g NaCl and the percent yield of NaCl was 85.196 % NaCl. These numbers explain exactly how much of each reactant and product were used/produced in the reaction. .
The balanced equation used to help figure out those numbers is: .
NaHCO3 (s) + HCL (l) Ã NaCl (s) + H2CO3.
H2CO3 Ã H2O(l) + CO2 (g).
In the experiment, HCL was slowly added to NaHCO3 into the dish and covered with the watch glass. The mixture was then slowly heated until only a white residue remained. The heating evaporated the HCL, yielding NaCl and H2CO3. The NaCl was formed by a double reaction; Sodium chloride and carbonic acid were formed from hydrochloric acid and baking soda (sodium bicarbonate). The H2CO3 further breaks down to yield H2O and CO2. We can see all this by looking at the balanced equation.
Sometimes in an experiment, your outcome might not be what you expected to get, and the most common reason for this is human error.