Mass - Mole Relationship                                                  Name ___________________________________

                                                                                                Period ______ Date _______________________

Objective

            After completing this experiment, you should be able to verify experimentally the mass and mole relationships between reactants and products in a chemical reaction.

Equipment and Materials:

            Balance                                                         Wire gauze                                       spatula

            ring stand                                                     eye dropper                                       iron ring

            graduated cylinder                                     burner and tubing                          evaporating dish

            Sodium hydrogen carbonate                    3 M Hydrochloric acid

Safety

            Wear your goggles and apron at all times. Hydrochloric acid is caustic and corrosive. Avoid contact with skin and breathing vapors. If any acid should spill on you, immediately flush the are with water  and then notify your teacher. Keep long hair and loose clothing away from flame.

Procedure

1. Place  an evaporating dish on top of a watch glass. Measure the mass of the dry dish and watch glass. Record this mass

2. Add 2-3 g of sodium hydrogen carbonate to the evaporating dish. Measure the mass of the dish, watch glass and sodium hydrogen carbonate. Record this mass

3. Slowly add 10 mL of hydrochloric acid to the sodium hydrogen carbonate in the dish. Then carefully add hydrochloric acid with the dropper until the bubbling stops.

4. Place the evaporating dish on the wire gauze on the ring stand. Place the watch glass concave side upon top of the dish, but tipped slightly so that steam can escape.

5. Gently heat the dish with a small flame until only a dry solid remains. Make sure no water droplets remain on the underside of the watch glass.

6. Turn off the burner and allow the apparatus to cool for at least 10 minutes. Determine the mass of the cooled assembly (watch glass, dish and solid).

7. Rinse the residue down the drain. Clean your lab area. Wash your hands.

Data and observations: Make your own data table, and record observations here.

Calculations.

1. Find the mass of the reactant, NaHCO₃

2.  Find the moles of the reactant, NaHCO₃

3.  Find the mass of the product, NaCl

4. Moles of NaCl produced.

5. What is the mole ratio of products to reactant (NaCl NaHCO₃) from experiment?

6. Assuming the products are NaCl, CO₂, and H₂O, write a balanced equation for this reaction.

7. What is the mole ratio of NaCl to NaHCO₃ in this equation.

8. Calculate the percent error in this experiment using this formula