The kids are working on Stoichiometry. Let me share my slideshow about Stoichiometry. Here is the worksheet for the calculations. My kids are each getting different reactants, such as these reactant pairs. Epsom salts are magnesium sulfate decahydrate. Driveway Heat is calcium chloride dihydrate. These two compounds form a precipitate. Epsom salts, magnesium sulfate decahydrate, and sodium carbonate, or washing soda, also forms a precipitate. Calcium chloride and baking soda, sodium bicarbonate, also form a precipitate. (This link has the complete unit for precipitates with the handouts.) My point is you only need one set of reactants for this lab. It’s cheap! It’s also an excellent way to evaluate if your teen understands Stoichiometry.
For the Can you make 2 grams lab?, use these instructions for the reaction between calcium chloride and sodium carbonate (Driveway Heat and washing soda.). The goal is to determine how much of each reactant is needed to produce two grams of the precipitate, calcium carbonate.
Step 1. Write and balance the equation.
Step 2. Convert 2 grams of the precipitate to moles of precipitate.
Step 3. Apply the mole ratios to determine how many moles of each reactant are needed.
Step 4. Convert the moles to grams of each reactant.
Step 5. Mix each the mass of reactant separately into 50 mL of water, then combine. Allow to form the precipitate, filter out the precipitate, and allow to dry. Weigh the dry precipitate and calculate the percent error.
Step 6. Write a formal lab report using this lab report rubric.
Most of the online home-schools require four formal lab reports each year. I assign this lab because the kids hate it. Teens usually hate writing lab reports, too. Why spoil a fun lab? We might as well just add to the misery of the 2 Grams lab.
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