Eam 1 Review The answers to this sample eam are on the last page of this handout. Please note that the eam will be a combination of multiple choice and problem solving. For practice solving problems, please refer to the lecture notes, suggested problems and homework assignments. 1. The number of significant figures in 8.5001 10-2 is a. 3. b. 4. c. 5. d. 6. 7. 2. How many significant figures are there in the value 4,750,330? a. 7 b. 6 d. 4 3 c. 5 3. The distance between atoms is sometimes given in picometers, where 1 pm is equivalent to 1 10-12 m. If the distance between the carbon atoms in diamond is 1.54 10-8 cm, what is this distance in picometers? a. 0.154 b. 1.54 c. 154 d. 1,540 154,000 4. The volume of a 10.0% glucose solution is 8.25 ml. Its density is 1.039 g/ml. What mass does the solution have? a. 8.25 g d. 0.00825 kg b. 8.57 g 825 mg c. 0.0857 kg 5. What is the best answer to report for a. 2.3782 b. 2.378 c. 2.38 3.478 1.164 + 0.354? 2.00 d. 2.4 2 6. Which of the following have the correct number of significant figures and units for the mathematical operation 5.25 10 5 ergs 1.000 J 1.000 10 7 ergs 1.000 cal 4.184 J 1 kcal? 1000 cal a. 1.255 10-5 J/cal b. 1.255 10-5 kcal c. 1.25 10-5 kcal d. 1.3 10-5 kcal 1 10-5 kcal 7. Liquid propane boils at 42 C. What is its boiling point on the Kelvin scale? a. 231 K b. 256 K d. 315 K 345 K c. 273 K 8. The melting point and the normal boiling point of water can be used to calibrate thermometers. What are these respective temperatures in Kelvin degrees? a. 32 and 212 d. 0 and 373 b. 0 and 100 273 and 373 c. 100 and 273 Eam 1 Review Distributed on Monday, October 7, 2002 Page 1 of 5
9. How many scruples are there in 25.8 lb? Which of the following represents a correct setup to solve the problem? Some equivalents that may be helpful are given below: a. = 1.00 g = 15.4 grains = = 1.00 kg = 2.205 lb 1.00 kg 2.205 lb 1000 g 25.8 lb 1 kg b. 1.00 g 15.4 grains 25.8 lb c. 15. 4 grains 100. g 25.8 lb d. 1.54 grains 1.00 g 25.8 lb 1.00 kg 25.8 lb 2.205 lb 10. What is the mass of NH 3 in a 50.0-cm 3 sample that has a density of 0.90 g/cm 3 and which consists of 28% NH 3? a. 13 g d. 32 g b. 15 g 45 g c. 25 g 11. Calculate the mass of magnesium that occupies the same volume as 75.0 g of copper. The density of Cu = 8.96 g/cm 3 and Mg = 1.74 g/cm 3. a. 14.56 g d. 386 g b. 14.6 g 386.2 g c. 15 g 12. Which of the following is an eample of a chemical change? a. water boiling b. ice melting c. alcohol evaporating d. iodine vaporizing a sunburn 13. How many neutrons are there in the chloride ion, 37 17 Cl-? a. 17 b. 18 c. 20 d. 21 38 123 14. How many protons, neutrons, and electrons are in the antimony(iii) ion, 51Sb a. 123p, 72n, 123e b. 51p, 72n, 48e c. 51p, 72n, 51e d. 72p, 51n, 69e 48p, 72n, 51e 3+? Eam 1 Review Distributed on Monday, October 7, 2002 Page 2 of 5
15. An atom that has the same number of neutrons as 59 Co is a. 59 Ni. b. 57 Co. c. 60 Cu. d. 58 F 58 Ni. 16. The atomic mass of Ga is 69.72. There are only two naturally occurring isotopes of gallium, 69 Ga with a mass of 69.0 and 71 Ga with a mass of 71.0. The natural abundance of the 71 Ga isotope must be approimately a. 20%. b. 40%. c. 50%. d. 60%. 80%. 17. The neutral atoms of all the isotopes of the same element have a. different numbers of protons. d. the same mass numbers. b. equal numbers of neutrons. c. the same number of electrons. the same masses. 18. An element, X, has the following isotopic composition: X-200, 90%; X-199, 8.0%; and X-202, 2.0%. Its atomic mass is CLOSEST to a. 199 amu. d. 202 amu. b. 200 amu. c. 201 amu. It cannot be determined. 19. One gram of TNT, C 7 H 5 N 3 O 6, has 7.95 10 21 nitrogen atoms. How many hydrogen atoms are there in 1.00 g of TNT? a. 7.95 10 21 d. 1.59 10 22 b. 9.26 10 21 1.86 10 22 c. 1.33 10 22 20. The formulas of the carbonate ion, the ammonium ion, and the chlorate ion are represented, respectively, as a. CO 2-3, NH - 2, ClO - 3. d. CO 2-3, NH + 4, ClO - 3. b. CO 2-3, NH + 3, ClO - 2. P 3-, NH + 3, ClO - 2. c. CO - 2, NH + 4, ClO -. 21. The chemical formula for iron(iii) sulfide is a. Fe 2 (SO 3 ) 3. b. Fe 2 (SO 4 ) 3. c. Fe 2 S 3. d. Fe 3 (SO 3 ) 2. Fe 3 (SO 4 ) 2. 22. The group(s) that readily form cations is (are) the 1. alkali elements. 2. halogen elements. 3. transition elements. a. 1 only b. 2 only c. 3 only d. 1 and 2 only 1 and 3 only Eam 1 Review Distributed on Monday, October 7, 2002 Page 3 of 5
23. What is the molar mass of ammonium sulfate, (NH 4 ) 2 SO 4, an important synthetic fertilizer? a. 70. g/mol d. 132 g/mol b. 92 g/mol 146 g/mol c. 114 g/mol 24. How many aluminum atoms are there in 25 g of Al 2 S 3? a. 1.0 10 23 b. 2.0 10 23 c. 4.5 10 23 d. 4.0 10 21 6.0 10 21 25. How many molecules are there in 176 g of ascorbic acid, C 6 H 8 O 6? a. 88 6.0 10 b. 176 c. 6.02 10 23 176 d. 176 6.0 10 23 26. Sodium cyclamate, C 6 H 11 NHSO 3 Na, was used at one time as an artificial sweetener. C 6 H 11 NHSO 3 Na has a molecular mass of 201.2 g/mol. How many moles of sodium cyclamate are contained in a 25.6-g sample? a. 0.127 b. 0.193 c. 0.245 d. 7.86 5180 23 27. Calculate the number of moles of bromine present in 30.0 ml of Br 2 (l) whose density is 3.12 g/ml. a. 0.586 d. 2.34 b. 1.17 c. 1.83 2.75 28. What is the percentage of chlorine in DDT, C 14 H 9 Cl 5? a. 35.0 b. 40.0 c. 45.0 d. 50.0 55.0 29. What is the percentage of mass of oygen in vanillin, C 8 H 8 O 3, which is used as a flavoring? a. 27.3% d. 63.2% b. 31.6% c. 45.8% 68.4% 30. Analysis of a hydrocarbon showed that it contained 14.4% hydrogen and 85.6% carbon by weight. What is its simplest formula? a. CH d. C 2 H 3 b. CH 2 C 2 H 5 c. CH 3 Eam 1 Review Distributed on Monday, October 7, 2002 Page 4 of 5
Answers: 1. C 2. B 3. C 4. B 5. C 6. C 7. A 8. E 9. D 10. A 11. B 12. E 13. C 14. B 15. D 16. B 17. C 18. B 19. C 20. D 21. C 22. E 23. D 24. B 25. C 26. A 27. A 28. D 29. B 30. B Eam 1 Review Distributed on Monday, October 7, 2002 Page 5 of 5