Chemistry Coursework

Name:______________________________ Date Due:_____________

Limiting Reactants - Determining final product amounts.

Limiting Reactant Calculation

Part 1

Baking soda (NaHCO3) is often used as an antacid. It neutralizes excess hydrochloric acid in the stomach by forming the weaker carbonic acid and sodium chloride.

If baking soda is to work as a medication and actually relieve an upset stomach, it would have to be consumed in sufficient quantity to neutralize the acid but not so much as to cause other digestive problems when excess baking soda moves past the stomach.

If, for example, there were 15 grams of HCl in someone’s stomach and they wanted to consume baking soda to make themselves feel better. would a single 20 gram dose be too little, too much, or just right?

1. Write a balanced chemical reaction:

2. Use dimensional analysis and the molar mass of HCl to calculate how many moles of HCl are present:

3. Use dimensional analysis to calculate how many moles of baking soda are in 20 grams of baking soda:

4. Convert the moles of baking soda into moles of HCl using the balanced chemical equation:

5. Compare your answer above to the actual amount of HCl and decide which reactant is in excess:

6. Answer the question:

Part 2

1. In the reaction Mg3N2 + 6H2O -----> 3Mg(OH)2 + 2NH3, if the initial amount of Mg3N2 is 58.1g and the initial amount of H2O is 20.4g, what are the final masses of each species (reactants and products)?

2. In the reaction Au2S3 + 3H2 -------> 3H2S + 2Au, if the initial amount of Au2S3 is 500.20 g and the initial amount of H2 is 5.67g, what is the theoretical yield amount of gold in grams?

3. The important industrial chemical acrylonitrile, a monomer in the formation of ABS plastics (Legos!) The reaction to synthesize it looks like this: 2C3H6 + 2NH3 + 3O2 ------> 2C3H3N + 6H2O, if the initial amounts are C3H6 22.5g, NH3 20.6 g, and O2 18.1 g, what will be the limiting reactant?