AP/IB Chemistry Summer Work Work these problems on a separate sheet of paper. Show all of your work, all units, and correct significant figures for full credit. These problems will be collected Wednesday August 19 (first full day of school) and entered as your first grade in this class. As I have provided answers for several problems, this is graded on completion as well as correctness. You may work with other students on the problems but may not copy their work. Please pledge this work to indicate that you did not copy another student’s work. Good luck! 1. How many significant figures are there in each of the following values? a. 6.06 x 10-­‐15 b. 0.003840 c. 17.00 d. 8 x 108 e. 463.8052 f. 300 g. 301 h. 300. 2. Perform each of the following conversions. a. 8.43 cm to millimeters b. 2.41 x 102 cm to meters c. 294.5 nm to centimeters d. 1.445 x 104 m to kilometers e. 235.3 m to millimeters f. 903.3 nm to micrometers 3. Which of the following are chemical changes? Which are physical changes? a. The cutting of food b. Interaction of food with saliva and digestive enzymes c. Proteins being broken down into amino acids d. Complex sugars being broken down into simple sugars e. Making maple syrup by heating maple sap to remove water through evaporation f. DNA unwinding 4. For each of the following ions, indicate the number of protons and electrons the ion contains. a. Ba2+ b. Zn2+ c. N3-­‐ d. Rb+ e. Co3+ f. Te2-­‐ g. Br-­‐ 5. Name the following compounds. a. HC2H3O2 b. NH4NO2 c. Co2S3 d. ICl e. Pb3(PO4)2 f. KClO3 g. H2SO4 h. Sr3N2 i. Al2(SO3)3 j. SnO2 k. Na2CrO4 l. HClO 6. A diamond contains 5.0 x 1021 atoms of carbon. What amount of moles of carbon and what mass in grams of carbon are in this diamond? Ans. 0.0083 moles, 0.100 grams 7. What amount of moles is represented by each of these samples? a. 150.0 grams of Fe2O3 ans. 0.9393 moles b. 10.0 mg of NO2 ans. 2.17 x 10-­‐4 moles c. 1.5 x 1016 molecules of BF3 ans. 2.5 x 10-­‐8 moles 8. Calculate the percent composition by mass of the following compounds that are important starting materials for synthetic polymers: a. C3H4O2 (acrylic acid, from which acrylic plastics are made) Ans. 49.99% C, 5.61% H, 44.40% O b. C4H6O2 (methyl acrylate, form which Plexiglas is made) Ans. 55.8% C, 7.04% H, 37.2% O c. C3H3N (acrylonitrile, from which Orlon is made) Ans. 67.89% C, 5.71% H, 26.40% N 9. A compound that contains only carbon, hydrogen, and oxygen is 48.64% C and 8.16% H by mass. What is the empirical formula of this substance? Ans. C3H6O2 10. A compounds contains 47.08% carbon, 6.59% hydrogen, and 46.33% chlorine by mass; the molar mass of the compound is 153 g/mol. What are the empirical and molecular formulas of the compound? Ans. EF = C3H5N, MF = C6H10N2 11. Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is C7H6O3 + C4H6O3 ! C9H8O4 + HC2H3O2 a. What mass of acetic anhydride is needed to completely consume 1.00 x 102 grams of salicylic acid? Ans. 73.9 grams b. What is the maximum mass of aspirin (the theoretical yield) that could be produced in this reaction? Ans. 130. grams 12. What mass of NaOH is contained in 250.0 mL of a 0.400 M sodium hydroxide solution? Ans. 3.92 grams 13. A 25.00-­‐mL sample of hydrochloric acid solution requires 24.16 mL of 0.106 M sodium hydroxide for complete neutralization. What is the concentration of the original hydrochloric acid solution? Ans. 0.102 M 14. Give the complete electron configuration for: a. Sodium b. Chlorine c. Zinc d. Barium 15. Contrast, on the molecular level, the movement of particles in the different states of matter. 16. A 15.00 gram sample of sodium sulfate hydrate was found to contain 7.05 grams of water. Determine the empirical formula of the hydrate. Ans. Na2SO4 " 7H2O 17. How many mL of 3.0 M HCl are need to produce 2.00 L of hydrogen gas at STP from excess magnesium? Mg + 2HCl ! H2 + MgCl2 Ans. 59.5 ml 18. Challenge Problem: A student was given 2.94 grams of a mixture containing solid MgCl2 and KNO3 to determine the percentage by mass of MgCl2 in the mixture. The student added a solution containing excess AgNO3 to form a precipitate of solid AgCl. The silver chloride was filtered, dried, and weighed. The student determined the mass of the AgCl precipitate to be 4.25 grams. Calculate: a. The number of moles of MgCl2 in the original mixture b. The percent by mass of MgCl2 in the original mixture This is basic chemistry knowledge that you will need to use on a day-­‐to-­‐day basis in this class. These kinds of questions will appear in all sorts of problems so starting the year with a good foundation is important. If you still have your Honors Chemistry notes, which you should, you should try to incorporate those into your notebook for AP/IB or else keep them close by.