Stoichiometry Practice

Ace stoichiometry! Practice balancing equations, mole ratios, limiting reactants & percent yield.

1. Balance the following SKELETON equation: Al + H2SO4 → Al2(SO4)3 + H2 (fill all blanks, even if it is "1") 2 Al(s) + 3 H2SO4(aq) → 1 Al2(SO4)3 (aq)+ 3 H2(g) 2. For the above equation, after YOU have balanced it, what is the ratio of moles of H2SO4 to Al2(SO4)3 in the balanced equation? 1:1 3:1 1:3 2:3 3. Ammonia is one of the main nitrogen fertilizers. It is prepared by the reaction between molecular hydrogen and nitrogen. 3 H2(g) + N2(g) → 2 NH3How many moles of NH3 are produced if 4.5 moles of N2 react? 2 moles 2.25 moles 4.5 moles 9 moles 4. Consider the last chemical reaction equation: 3 H2(g) + N2(g) → 2 NH3How many grams of N2 are required to produce 3.8 moles of NH3? 1.9 grams of N2 3.8 grams of N2 53.2 grams of N2 17.031 grams of N2 5. Consider the last chemical reaction equation: 3 H2(g) + N2(g) → 2 NH3How many moles of H2 are required to produce 64.7 grams of NH3? 1.9 moles of H2 3.8 moles of H2 5.7 moles of H2 11.4 moles of H2 6. Consider the last chemical reaction equation. 3 H2(g) + N2(g) → 2 NH3 (l) What volume of H2 is needed to produce 4.7 moles of NH3? 7.05 Liters H2 52.6 Liters H2 70.2 Liters H2 315.8 Liters H2 7. Phosphine is prepared by the reaction between molecular hydrogen and phosphorus as shown below.6 H2(g) + P4(s) → 4 PH3How many grams of PH3 are produced if 185.7 grams of P4 react? 13.1 grams PH3 204 grams PH3 124 grams PH3 8. Using the same reaction: 6 H2(g) + P4(s) → 4 PH3How many grams of PH3 are produced if 201.6 liters of H2 are used in this reaction? 204 g of PH3 136 g of PH3 90.6 g of PH3 9. Using the same equation again: 6 H2(g) + P4(s) → 4 PH3 and remembering the Law of Conservation of Mass;How many grams of H2 and P4 are needed to produce 12 g of PH3? 123.896 g of P4 and 2.016 g of H2 7.2 g of P4 and 4.8 g of H2 10.9 g of P4 and 1.1g of H2 0.087 g of P4 and 0.525 g of H2 This problem will involve a limiting reactant. Remember the limiting reactant determines how much product can be made. We will use the following reaction: 3FeCl2 + 2Na3PO4 → Fe3(PO4)2 + 6 NaClIf 25 grams of Iron (II) Chloride and 40 grams of Sodium phosphate are mixed together, how much sodium chloride can be produced? The limiting reactant is FeCl2, and 22.8 grams of salt is made. The limiting reactant is Na3PO4, and 42.7 grams of salt is made. The limiting reactant is FeCl2, and 42.7 grams of salt is made. The limiting reactant is Na3PO4, and 22.8 grams of salt is made. This last question concerns PERCENT YIELD. If we use the same reaction as in the previous question, our balanced equation is 3FeCl2 + 2Na3PO4 → Fe3(PO4)2 + 6 NaCl If 100 grams of FeCl2 reacts, and in the lab, 87.0 grams of NaCl is recovered, what is the percent yield? 87% 92.2% 94%