1. P UTTING IT ALL TOGETHER Mrs. Callender – Unit 7 - Stoichiometry

2. L ESSON E SSENTIAL Q UESTION Can I calculate the mass of a product before actually doing the reaction?

3. STOICHIOMETRY - The study of quantities of materials consumed and produced in chemical reactions.

4. M ASS -M ASS S TOICHIOMETRY If 20.0 grams of zinc pellets reacts with excess hydrochloric acid, how many grams of zinc chloride are going to be produced? 1. Write a balanced equation. Zn (s) + 2 HCl (aq)  ZnCl 2(s) + H 2(g) 2.Write the “given” information from the problem under the corresponding chemical compound 20.0 gexcess ? grams 3.Write down any information necessary to change the given measurements to moles. (i.e. molar mass or molar volume at STP.) 65.39 g/mole 136.29 g/mole 4. Start the problem with your “given” over one. 20.0 g Zn 1 X 65.39 g Zn 1 mole Zn X 1 mole ZnCl 2 6. “Stoichiometry” Step. This step allows you to go from one compound to another “legally”. Only use the coefficients in front of the compounds involved in the problem X 1 mole ZnCl 2 136.29 g ZnCl 2 = 7. Convert moles to appropriate answer unit and use the calculator to solve the problem. 41.7 g ZnCl 2 solid5.Using the information under your “given” and convert grams to moles. 1 1

5. M ASS -M ASS S TOICHIOMETRY 6.50 grams of aluminum foil reacts with excess oxygen, how many grams of aluminum oxide are going to be produced? 1. Write a balanced equation. 4 Al (s) + 3 O 2(g)  2 Al 2 O 3(s) 2.Write the “given” information from the problem under the corresponding chemical compound 6.50 gexcess ? grams 3.Write down any information necessary to change the given measurements to moles. (i.e. molar mass or molar volume at STP.) 26.98 g/mole 101.96 g/mole 4. Start the problem with your “given” over one. 6.50 g Al 1 X 26.98 g Al 1 mole Al X 4 mole Al 2 mole Al 2 O 3 6. “Stoichiometry” Step. This step allows you to go from one compound to another “legally”. Only use the coefficients in front of the compounds involved in the problem X 1 mole Al 2 O 3 101.96 g Al 2 O 3 = 7.Convert moles to the appropriate unit using gathered information, Calculate answer. 12.28 g Al 2 O 3 solid 5.Using the information under your “given” and convert grams to moles.

6. M ASS -V OLUME S TOICHIOMETRY How many liters of oxygen gas, at STP can be collected from the complete decomposition of 50.0 g of potassium chlorate 1. Write a balanced equation. 2.Write the “given” information from the problem under the corresponding chemical compound 50.0 g ? Liters at STP 3.Write down any information necessary to change the given measurements to moles. (i.e. molar mass or molar volume at STP.) 122.55 g/mole 22.4 L/mole 4. Start the problem with your “given” over one. 50.0 g KClO 3 1 X 122.55 g KClO 3 1 mole KClO 3 X 2 mole KClO 3 3 mole O 2 6. “Stoichiometry” Step. This step allows you to go from one compound to another “legally”. Only use the coefficients in front of the compounds involved in the problem X 1 mole O 2 22.4 L O 2 = 7.Convert moles to the appropriate unit using gathered information, Calculate answer. 13.71 L O 2 gas 5.Using the information under your “given” and convert grams to moles. 2 KClO 3(s)  2 KCl (s) + 3 O 2(g)