CHE 105 Spring 2018 Exam 2

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1 CHE 105 Spring 2018 Exam 2 Your Name: Your ID: Question #: 1 A penny contains 373 x 10 2 moles of zinc How many atoms of zinc are in a penny? A 225 x atoms B 221 x atoms C 375 x atoms D 2755 x atoms Question #: 2 For which one will 1 mole of atoms of the element have the largest mass? A carbon B lithium C calcium D sulfur Question #: 3 What is the molar mass of nicotine, C10H14N2? A 134 g/mol B 148 g/mol C 158 g/mol D 162 g/mol E 210 g/mol

2 Question #: 4 One peanut contains 800 milligrams of sucrose The molecular formula of sucrose is C12H22O11 (molar mass = 3423 g/mol) How many moles of sucrose are in a peanut? A 234 x 10 4 moles B 433 x 10 5 moles C 333 x 10 3 moles D 133 x 10 2 moles Question #: 5 What percentage by mass is carbon in Al4C3? A 197 % B 222 % C 250 % D 317 % E 412 % Question #: 6 How many atoms of chlorine are in 500 moles of Freon, CCl2F2? 1 Report your answers with three significant figures Do NOT include units in your answer Use the format 222E2 or 222E 2 for numbers in scientific notation 1

3 Question #: 7 What is the empirical formula of a compound that is 62% carbon, 104% hydrogen, and 275% oxygen by mass? A C3HO B C6HO3 C C6H12O2 D C5H10O E C3H6O Question #: 8 What is the molecular formula for a compound that has a molar mass of 920 g/mol and an empirical formula of NO2? A N2O3 B N3O6 C N2O4 D N4O8 E N2O5 Question #: 9 When nail polish dissolves in ethyl acetate (nail polish remover), ethyl acetate is the 1 [solvent, solute] and nail polish is the 2 [solvent, solute] 1 2

4 Question #: 10 One liter of pure water contains 1000 grams of H2O What is the molarity (M) of water? A 5551 M B 189 x 10 4 M C 1760 x 10 2 M D 1000 M E 1000 M Question #: 11 How many moles of ethanol, CH3CH2OH, are contained in 548 ml of M ethanol solution? A mol B mol C mol D mol E mol Question #: 12 If 234 ml of water is added to a beaker that already contains 766 ml of a 150 M solution of NaCl, what is the final concentration of the solution? 1 M Report your answer with three significant figures Do NOT include units in your answer 1

5 Question #: 13 Which equation shows the balanced reaction of ethane with molecular oxygen to form carbon monoxide and water vapor? A 2C2H6(g) + 7O2(g) 4CO2(g) + 4H2O(g) B C2H6(g) + 5O(g) 2CO(g) + 3H2O(g) C 2C2H6(g) + 5O2(g) 4CO(g) + 6H2O(g) D C2H6(g) + 7O(g) 2CO2(g) + 3H2O(g) Question #: 14 Which compound is the precipitate in the following reaction? K2CO3(aq) + NiCl2(aq)? A NiCO3 B Ni3CO3 C KCl D KCl2 Question #: 15 Based on the solubility rules, which compound should be soluble in water? A (NH4)3PO4 B Ca3(PO4)2 C AlPO4 D Ag3PO4

6 Question #: 16 Which two statements are true regarding strong electrolytes? A Solutions of strong electrolytes conduct electricity B Solutions of strong electrolytes do not conduct electricity C Strong electrolytes will completely dissociate (or ionize) in water D Strong electrolytes will partially dissociate (or ionize) in water Question #: 17 When dissolved in water, acids produce 1 ions, while bases dissolve in water to yield 2 ions 1 2 Question #: 18 What are the two spectator ions in the reaction? Pb(NO3)2(aq) + H2SO4(aq) PbSO4(s) + 2HNO3(aq) A Pb 2+ (aq) B H + (aq) C NO3 (aq) D SO 4 2 (aq)

7 Question #: 19 What is the oxidation number of chromium in the dichromate anion, Cr2O7 2? A +4 B +6 C +8 D +10 E +12 Question #: 20 In the reaction shown below, 1 is oxidized and 2 is the reducing agent Ni(s) + 2AgClO4(aq) Ni(ClO4)2(aq) + 2Ag(s) 1 2 Question #: 21 When the following redox reaction is balanced with the smallest possible whole number coefficients, what is the coefficient of elemental lithium? Li(s) + O2(g) Li2O(s) A 1 B 2 C 3 D 4

8 Question #: 22 Which two are weak acids in aqueous solutions? A acetic acid, C2H4O2 B hydroiodic acid, HI C percholoric acid, HClO4 D nitric acid, HNO3 E citric acid, C6H8O7 Question #: 23 Which two equations represent the ionization of a strong acid? A HCl(aq) H + (aq) + Cl (aq) B HNO3(aq) + H2O(l) H3O + (aq) + NO3 (aq) C NaOH(aq) Na + (aq) + OH (aq) D HCl(aq) + NaOH(aq) H2O(l) + NaCl(aq) E NaCl(aq) Na + (aq) + Cl (aq) Question #: 24 Automotive air bags inflate when sodium azide decomposes explosively into its constituent elements 2NaN3(s) 2Na(s) + 3N2(g) How many moles of N2 are produced by the decomposition of 288 mol of sodium azide? A 192 mol B 864 mol C 432 mol D 0960 mol E 144 mol

9 Question #: 25 What is the limiting reactant when 40 g of magnesium reacts with 38 g of molecular oxygen? 2Mg(s) + O2(g) 2MgO(s) A magnesium B molecular oxygen C They are present in equimolar amounts, so neither is limiting Question #: 26 How many moles of BCl3 are needed to produce 100 g of HCl? BCl3(g) + 3H2O(l) 3HCl(aq) + B(OH)3(aq) A mol BCl3 B 0274 mol BCl3 C 0832 mol BCl3 D 317 mol BCl3 Question #: 27 When 110 g of calcium metal reacts with water, 500 g of calcium hydroxide (molar mass = 7410 g/mol) is produced Given the balanced equation, what is the percent yield of the reaction? Ca(s) + 2H2O(l) Ca(OH)2(aq) + H2(g) A 123% B 246% C 455% D 619% E 840%

10 Question #: 28 What volume of a 0300 M KCl solution will completely react with 200 L of a 0400 M Pb(NO3)2 solution based on the balanced chemical equation? 2KCl(aq) + Pb(NO3)2(aq) PbCl 2(s) + 2KNO 3(aq) A 533 L B 392 L C 451 L D 283 L Question #: 29 From the balanced equation for the titration reaction, how many ml of M phosphoric acid are required to neutralize 4500 ml of M barium hydroxide solution? 3Ba(OH)2(aq) + 2H3PO4(aq) Ba3(PO4)2(s) + 6H2O(l) A 304 ml B 150 ml C 225 ml D 338 ml Question #: 30 What is the concentration in ppm (parts per million) of mercury in a 500 g sample of industrial wastewater containing 048 mg of mercury? A ppm B 4800 ppm C 96 ppm D 96 ppm

DRAFT Do Not Use Until Posted CHE 105 Spring 2018 Exam 2 - Confidential Your Name: Your ID: attachment_for_pubexamuid_lnxp115197488942858838xx_252jpg Question #: 1 A penny contains 373 x 10 2 moles

11 DRAFT Do Not Use Until Posted CHE 105 Spring 2018 Exam 2 - Confidential Your Name: Your ID: attachment_for_pubexamuid_lnxp xx_252jpg Question #: 1 A penny contains 373 x 10 2 moles of zinc How many atoms of zinc are in a penny? A 225 x atoms B 221 x atoms C 375 x atoms D 2755 x atoms Question #: 2 For which one will 1 mole of atoms of the element have the largest mass? A carbon

12 B lithium C calcium D sulfur Question #: 3 What is the molar mass of nicotine, C 10 H 14 N 2? A 134 g/mol B 148 g/mol C 158 g/mol D 162 g/mol E 210 g/mol Question #: 4 One peanut contains 800 milligrams of sucrose The molecular formula of sucrose is C 12 H 22 O 11 (molar mass = 3423 g/mol) How many moles of sucrose are in a peanut? A 234 x 10 4 moles B 433 x 10 5 moles C 333 x 10 3 moles D 133 x 10 2 moles Question #: 5 What percentage by mass is carbon in Al 4 C 3? A 197 % B 222 % C 250 % D 317 % E 412 %

13 Question #: 6 How many atoms of chlorine are in 500 moles of Freon, CCl 2 F 2? 1 Report your answers with three significant figures Do NOT include units in your answer Use the format 222E2 or 222E 2 for numbers in scientific notation 1 602E24 Question #: 7 What is the empirical formula of a compound that is 62% carbon, 104% hydrogen, and 275% oxygen by mass? A C 3 HO B C 6 HO 3 C C 6 H 12 O 2 D C 5 H 10 O E C 3 H 6 O Question #: 8 What is the molecular formula for a compound that has a molar mass of 920 g/mol and an empirical formula of NO 2? A N 2 O 3 B N 3 O 6 C N 2 O 4 D N 4 O 8 E N 2 O 5 Question #: 9 When nail polish dissolves in ethyl acetate (nail polish remover), ethyl acetate is the 1 [solvent, solute] and nail polish is the 2 [solvent, solute]

14 1 solvent 2 solute Question #: 10 One liter of pure water contains 1000 grams of H 2 O What is the molarity (M) of water? A 5551 M B 189 x 10 4 M C 1760 x 10 2 M D 1000 M E 1000 M Question #: 11 How many moles of ethanol, CH 3 CH 2 OH, are contained in 548 ml of M ethanol solution? A mol B mol C mol D mol E mol Question #: 12 If 234 ml of water is added to a beaker that already contains 766 ml of a 150 M solution of NaCl, what is the final concentration of the solution? 1 M Report your answer with three significant figures Do NOT include units in your answer 1 115

15 Question #: 13 Which equation shows the balanced reaction of ethane with molecular oxygen to form carbon monoxide and water vapor? A 2C 2 H 6 (g) + 7O 2 (g) 4CO 2 (g) + 4H 2 O(g) B C 2 H 6 (g) + 5O(g) 2CO(g) + 3H 2 O(g) C 2C 2 H 6 (g) + 5O 2 (g) 4CO(g) + 6H 2 O(g) D C 2 H 6 (g) + 7O(g) 2CO 2 (g) + 3H 2 O(g) Question #: 14 Which compound is the precipitate in the following reaction? K 2 CO 3 (aq) + NiCl 2 (aq)? A NiCO 3 B Ni 3 CO 3 C KCl D KCl 2 Question #: 15 Based on the solubility rules, which compound should be soluble in water? A (NH 4 ) 3 PO 4 B Ca 3 (PO 4 ) 2 C AlPO 4 D Ag 3 PO 4 Question #: 16 Which two statements are true regarding strong electrolytes? A Solutions of strong electrolytes conduct electricity B Solutions of strong electrolytes do not conduct electricity

16 C Strong electrolytes will completely dissociate (or ionize) in water D Strong electrolytes will partially dissociate (or ionize) in water Question #: 17 When dissolved in water, acids produce 1 ions, while bases dissolve in water to yield 2 ions 1 hydronium hydrogen H+ H3O+ 2 hydroxide OH- Question #: 18 What are the two spectator ions in the reaction? Pb(NO 3 ) 2 (aq) + H 2 SO 4 (aq) PbSO 4 (s) + 2HNO 3 (aq) A Pb 2+ (aq) B H + (aq) C NO 3 (aq) D SO 4 2 (aq) Question #: 19 What is the oxidation number of chromium in the dichromate anion, Cr 2 O 7 2? A +4 B +6 C +8 D +10 E +12 Question #: 20

17 In the reaction shown below, 1 is oxidized and 2 is the reducing agent Ni(s) + 2AgClO 4 (aq) Ni(ClO 4 ) 2 (aq) + 2Ag(s) 1 Ni nickel Ni(s) 2 Ni nickel Ni(s) Question #: 21 When the following redox reaction is balanced with the smallest possible whole number coefficients, what is the coefficient of elemental lithium? Li(s) + O 2 (g) Li 2 O(s) A 1 B 2 C 3 D 4 Question #: 22 Which two are weak acids in aqueous solutions? A acetic acid, C 2 H 4 O 2 B hydroiodic acid, HI C percholoric acid, HClO 4 D nitric acid, HNO 3 E citric acid, C 6 H 8 O 7 Question #: 23 Which two equations represent the ionization of a strong acid? A HCl(aq) H + (aq) + Cl (aq) B HNO 3 (aq) + H 2 O(l) H 3 O + (aq) + NO 3 (aq)

18 C NaOH(aq) Na + (aq) + OH (aq) D HCl(aq) + NaOH(aq) H 2 O(l) + NaCl(aq) E NaCl(aq) Na + (aq) + Cl (aq) Question #: 24 Automotive air bags inflate when sodium azide decomposes explosively into its constituent elements 2NaN 3 (s) 2Na(s) + 3N 2 (g) How many moles of N 2 are produced by the decomposition of 288 mol of sodium azide? A 192 mol B 864 mol C 432 mol D 0960 mol E 144 mol Question #: 25 What is the limiting reactant when 40 g of magnesium reacts with 38 g of molecular oxygen? 2Mg(s) + O 2 (g) 2MgO(s) A magnesium B molecular oxygen C They are present in equimolar amounts, so neither is limiting Question #: 26 How many moles of BCl 3 are needed to produce 100 g of HCl? BCl 3 (g) + 3H 2 O(l) 3HCl(aq) + B(OH) 3 (aq) A mol BCl 3

19 B 0274 mol BCl 3 C 0832 mol BCl 3 D 317 mol BCl 3 Question #: 27 When 110 g of calcium metal reacts with water, 500 g of calcium hydroxide (molar mass = 7410 g/mol) is produced Given the balanced equation, what is the percent yield of the reaction? Ca(s) + 2H 2 O(l) Ca(OH) 2 (aq) + H 2 (g) A 123% B 246% C 455% D 619% E 840% Question #: 28 What volume of a 0300 M KCl solution will completely react with 200 L of a 0400 M Pb(NO 3 ) 2 solution based on the balanced chemical equation? 2KCl(aq) + Pb(NO 3 ) 2 (aq) PbCl 2 (s) + 2KNO 3 (aq) A 533 L B 392 L C 451 L D 283 L Question #: 29 From the balanced equation for the titration reaction, how many ml of M phosphoric acid are required to neutralize 4500 ml of M barium hydroxide solution? 3Ba(OH) 2 (aq) + 2H 3 PO 4 (aq) Ba 3 (PO 4 ) 2 (s) + 6H 2 O(l)

20 A 304 ml B 150 ml C 225 ml D 338 ml Question #: 30 What is the concentration in ppm (parts per million) of mercury in a 500 g sample of industrial wastewater containing 048 mg of mercury? A ppm B 4800 ppm C 96 ppm D 96 ppm

CHE 105 FA17 Exam 2. How many moles of beryllium are in 15.0 grams of Be?

CHE 105 FA17 Exam 2. How many moles of beryllium are in 15.0 grams of Be? CHE 105 FA17 Exam 2 Your Name: Your ID: Question #: 1 How many moles of beryllium are in 150 grams of Be? A 66 B 13515 C 901 D 0601 Question #: 2 Vanillin, C8H8O3, is the molecule responsible for the vanilla