Exam 1
Chem 115
January 30, 2008
Prof. Stephen Drucker
1. Please do not open the exam until instructed to do so.
2. Please ensure that both your name and university I.D. number are written on your answer sheet.
3. A periodic table is included as the last page of the exam.
4. You may use a calculator, but you may not access any data stored in its memory. You may not use your cell
phone or internet-connected device in place of a calculator.
5. Each question has only one correct answer. Your response will be counted as incorrect if you choose more
than one answer.
6. 20 questions are on the exam. The first ten are worth 2 points each. The remaining questions are worth 3 points
each.
7. You may keep this booklet of questions. Turn in only the computer answer form.
8. Good luck! Answers will be sent to you by email this afternoon.
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Solubility Guidelines
All nitrates, acetates, and perchlorates are soluble.
Halides (halogen anions) are generally soluble, except in compounds
containing lead(II) or silver.
Sulfates are generally soluble, except in compounds containing calcium
or barium.
Carbonates are generally insoluble, except in compounds containing
ammonium or Group 1 cations.
The following 10 questions are worth 2 points each:
1. Which of the following elements is most likely to form an anion? [2.7]
A) Ba B) K C) Cs D) Sr E) O
2. Which of the following is not an ionic compound? [2.7]
A) CO2 B) NaOH C) KCl D) Na2SO4 E) LiClO4
3. An ionic compound has the formula M2(SO4)3. What is the charge on M? [2.8]
A) +3 B) +2 C) +6 D) +1 E) –2
4. What answer should be reported if 4.560 is added to 2.6 × 10 –3? [1.6]
A) 4.563 B) 4.56 C) 4.6 D) 4.5626 E) 7.2
5. How many moles of carbon monoxide gas are produced when 2.88 moles of SnO 2(s) react with excess
carbon according to the equation below? [3.4]
SnO2(s) + 2C(s)  Sn(s) + 2CO(g)
A) 2.88 mol B) 1.44 mol C) 11.5 mol D) 5.76 mol E) 1.432 mol
6. The name of NO2– is the [2.8]
A) nitrous ion.
B) nitrite ion.
C) nitrate ion.
D) nitride ion.
E) pernitrate ion.
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7.
Which of the measured numbers below has the greatest number of significant figures? [1.6]
A) 6.02350 B) 0.0060235 C) 0.00060235 D) 6.0235 × 10 3 E) 60235.
8. The number of protons, neutrons, and electrons, respectively, in a neutral atom of 121Sb is [2.5]
A) 51 protons, 51 neutrons, and 51 electrons
B) 70 protons, 51 neutrons, and 70 electrons
C) 51 protons, 70 neutrons, and 51 electrons
D) 51 protons, 121 neutrons, and 51 electrons
E) 121 protons, 70 neutrons, and 121 electrons
9. Which of the following does not exist as molecules ? [2.7]
A) CH3COOH (liq.) B) Cl2 (g) C) ClO2 (g) D) KClO3 (s) E) HCl (g)
10. How many molecules are in 15 g CH4? [3.1]
A) 5.6 × 1022 B) 9.0 × 1023 C) 5.6 × 1023 D) 6.4 × 1023 E) 0.94
The following 10 questions are worth 3 points each:
11. How many moles of sodium sulfate must be added to an aqueous solution that contains excess barium
chloride in order to precipitate 0.50 moles of barium sulfate? [4.3]
A) 0.25 mol B) 1.5 mol C) 1.0 mol D) 0.50 mol E) 2.0 mol
12. When aqueous solutions of calcium chloride and ammonium carbonate are mixed, what are the "spectator
ions" in the reaction? [4.2, 4.3]
A) Ca2+ and CO32–
D) NH4+ and Cl–
B) Ca2+ and Cl–
E) Cl– and CO32–
C) NH4+ and CO32–
13. A sample of phosphorus of mass 3.654 g reacts with chlorine to form 16.20 g of a molecular compound.
What is the empirical formula of this compound? [3.2]
A) P3Cl B) PCl4 C) PCl2 D) PCl3 E) P2Cl3
14. Which of the following pairs of solutions will give a precipitate when mixed? [4.3]
A) Ca(C2H3O2)2(aq) and NH4Cl(aq)
D) K2SO4(aq) and Cu(NO3)2(aq)
B) NaC2H3O2(aq) and Hg(ClO4)2(aq)
E) KC2H3O2(aq) and NaI(aq)
C) AgNO3(aq) and LiCl(aq)
15. How many grams of chromium are in 75.0 g of chromium(VI) oxide? [3.1]
A) 26.4 g B) 1.33 g C) 39.0 g D) 69.3 g E) 144 g
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16.
A gold brick measures 2.00 × 4.00 × 8.00 in. If the density of gold is 19.3 g/cm3, what is the mass of the
brick in kg? (1 in = 2.54 cm) [1.5]
A) 3.14 kg B) 54.3 kg C) 20.2 kg D) 12.4 kg E) 1235 kg
17. How many moles of fluorine atoms are contained in 4.139 g of fluorine gas, F2? [3.1]
A) 9.181 mol B) 0.1089 mol C) 0.2178 mol D) 4.590 mol E) 78.64 mol
18. How many grams of titanium(IV) oxide are needed to have 0.850 mol? [3.1]
A) 95.1 g B) 10.6 g C) 67.9 g D) 94.0 g E) 54.3 g
19. Bismuth has a density of 9.80g/cm3. What is the volume of a chunk of bismuth that has a mass of 59.5 g?
[1.5]
A) 6.07 cm3 B) 9.80 cm3 C) 59.5 cm3 D) 583 cm3 E) 0.165 cm3
20. Consider the following reaction:
3NO2(g) + H2O(l)  2HNO3(l) + NO(g) [3.4]
How many moles of HNO3 are produced starting from 0.250 moles of NO2(g) and 0.100 moles of water?
Hint: one of the reactants is not used up completely.
A) 0.200 mol
B) 0.0833 mol
C) 0.500 mol
D) 0.375 mol
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E) 0.167 mol
Answer Key – Spring 08 Exam 1
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