MASS AND MOLE RELATIONSHIPS IN A CHEMICAL REACTION
PRE-LAB QUESTIONS
1. Balance the equation for the reaction of barium chloride with silver nitrate.
2. Predict the mole ratio of BaCl2 to AgCl for the equation.
3. If an experiment with 10.2 g barium chloride produced 14.5 g silver chloride, calculate the experimental mole ratio of silver chloride to barium chloride.
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MASS AND MOLE RELATIONSHIPS IN A CHEMICAL REACTION
Discussion: In this experiment, you will measure the mass of the solid reactant NaHCO3 and that of the solid products, NaCl. The experimental determination of these relative masses will enable you to determine their relative number of moles. As a result of your observations and calculations, you will determine the mass and mole relationships-the reacting ratios-of the solid reactants and products. The ratios of mass and moles are important in kitchen chemistry also. In some recipes, baking soda, NaHCO3, is used to cause a cake to “rise”. When a weak acid such as vinegar, or buttermilk, or lemon juice is added to the baking soda, bubbles of carbon dioxide are produced. For example
HC2H3O2 + NaHCO3 → H2O + CO2 + NaC2H3O2 Vinegar sodium sodium Bicarbonate acetate
This release of gas is what causes the cake to increase in size. However, because baking soda tastes bitter and acids taste sour, it is important to add them close to their reacting ratio so they will neutralize each other. This results in cakes and cookies that are neither bitter nor sour.
Procedure: 1. Place an evaporating dish on top of a watch glass. Measure the mass of the dry evaporating dish and the dry watch glass. Record this mass in your data table.
2. Add 2-3 g of sodium hydrogen carbonate to the evaporating dish. Measure the mass of the sodium hydrogen