Instructions. Answer each question in your own words. Also, be sure to show your calculations in your responses for questions that require you to use math. Remember, there is no plagiarism so use proper citations. 1. What is the mole, and why is it useful in chemistry? 2. Explain how you would determine the molar mass of C2H6. 3. What is stoichiometry, and what information is necessary to solve a stoichiometry problem? 4. How many grams of aluminum metal can be produced when 50.0 grams of aluminum chloride decompose? 2AlCl3 → 2Al + 3Cl2 5. Sometimes you are given a measured amount of two or more reactants and asked how much product can be formed. Explain what steps you would follow to solve this type of problem. 6. What is percent yield? Explain what it is and how it is calculated. 7. In a laboratory experiment, when 35.0 g Mg reacted in excess O2, the percent yield of MgO was 90.0%. What was the actual yield of that experiment?