CHEM 1128Q Final Exam Study Guide

In general chemistry 2 there are some new ideas that depend on your understanding of 2 new units of concentration in addition to the ones we learned about in General chemistry 1. These new units of concentration are molality (m) and Mole Fraction (z). This workshop is designed to help you review Molarity (M, from general chemistry 1) and then learn about what the new units of concentration (molality and mole fraction) mean. Molarity (M) is the numbers of moles of a substance per 1 liter of solution. You learned this last semester in topic 18. You also need to know to use the dilution formula: M_1V_1 = M_2V_2 general chemistry 2 is largely a course in aqueous solution chemistry and therefore molarity is probably the most important mole unit we will use all semester. You want to get really flood at using molarity and of course you also need to remember naming and stoichiometry. Before you write down your answers to these questions make sure that EVERYONE is comfortable with the content that is being tested. Take a moment to discuss your group and when you are sure you all agree on the correct answer*, write them down in the space provided below. You should ALL be able to do these types of questions in your sleep Spend no more than 25 minutes on the question in this section. 1. Consider a solution that is made by dissolving 6.5 g of calcium phosphate in 375 mL of water? Is calcium phosphate an. ionic compound or a covalent compound? What is the chemical formula for calcium phosphate? each. on to receive credit for this question. HOW many moles of calcium phosphate are there in 6.5 g of calcium phosphate? Finally, what is the molarity of the solution?

Synthesis of Benzocaine Obfectives:aToperform a Fischer Esterification reaction bj To analyze the product and calculate percent viclad Introduction: Benzocaine is used as a topical anesthctic that can be easily prepared using the Fischer E process. This is an acid catalyzed esterification reaction which will form from the following equilibrium General reaction: conc. H,SO H2N (eatalyst) ethyl p-aminobenzoate Benzocaine) Reference: "Experimental Organic Chemistry."Gilbert &Martin., Thomson - Brooks/Cole, 3* Ed. Copyright ©2002. Safety and Important Notes: . Concentrated sulfuric acid will burn skin. Gloves are recommended for this step. e Ethanol is highly flammable. Keep away from open flames. . Water can interfere with this reaction. Be sure your glassware is dry before beginning the experiment. The ethanol used cannot be tech. grade (which is always stored in the lab); you will need the very pure, reagent grade. Procedure: Place 1.00 grams of p-aminobenzoic acid and 10 mL of absolute ethanol, in a 25-mL round-bottom flask. Stir the mixture until the solid is completely dissolved. Add 1 mL of concentrated sulfuric acid drop wise to the ethanolic solution of p-aminobenzoic acid, and then set up a microscale reflux apparatus as shown in (figure 7.1 page 88 of Techniques in Organic Chemistry"). Heat the mixture under gentle reflux for 30 min. If any solid remains at this time, cool the flask add an additional 3 mL of absolute ethanol and 0.5 mL of concentrated sulfuric acid and continue to reflux. It is important for all of the solid to dissolve during the reflux period. Fischer Esterification Reaction Page Chemistry 223 Organic Laboratory, "Preparation of Benzocain,"