CHEM MISC General Chemistry I Spring 2020 – Exam 3 Version A Questions and Answers,100% CORRECT

CHEM MISC General Chemistry I Spring 2020 – Exam 3 Version A Questions and Answers Instructions: 1. Do NOT open this exam until you are told to do so. Opening the exam before the start of the exam is considered an act of Academic Dishonesty. 2. All answers must be bubbled into the scantron answer sheet. 3. No credit will be given for answers written on this exam. 4. You must use a #2 pencil to bubble in the answers on your scantron. 5. This is a multiple-choice exam consisting of 31 questions (8 pages). Each question is worth 6.67 points. There are a total of 206.77 points on this exam. 200 points is full credit. 6. Attached to the back of this exam you will find 2 blank pages, an appendix, and a periodic table. You may remove these from the exam at your convenience. 7. On the FRONT of your scantron. • Write your last name, followed by your first name. • Write your exam version (A or B) 8. On the BACK of your scantron: • Write and bubble in BOTH your last and first name. Make sure to bubble in your names as follows: Last Name (SPACE) First Name NOTE: You must Bubble in the space on your scantron! Multiple Choice Questions (6.67 pts each) 1) Consider the heating curve to the right. What is the physical state of the substance at 110 ˚C? a. Solid b. Solid and liquid c. Liquid d. Liquid and gas e. Gas 2) From the phase diagram shown to the right, estimate the normal boiling point. a. 0 ˚C b. 10 ˚C c. 25 ˚C d. 50 ˚C e. 75 ˚C 3) What is the molar mass of sodium bicarbonate (NaHCO3)? a. 84.02 g/mol b. 68.02 g/mol c. 100.02 g/mol d. 61.02 g/mol 4) How many moles of titanium(IV) chloride are there in 57.6 g? a. 3.29 moles b. 0.691 moles c. 0.254 moles d. 0.304 moles 5) How many moles of argon are there in 50.0 L at 100 ˚C and 1.0 atm. a. 1.63 moles b. 6.10 moles c. 0.612 moles d. 3.54 moles 6) If you make a 1.5 L solution with 65.6 g of iron(III) phosphate (FePO4) what is the molarity? a. 0.290 M b. 0.425 M c. 0.652 M d. 1.35 M 7) Rank these four molecules starting from LOWEST TO HIGHEST boiling point. a. I, II, III, IV b. VI, III, II, I c. I, IV, III, II d. I, IV, II, III e. I, II, IV, III 8) The balanced chemical equation for the reaction of iron with oxygen to make rust is 4Fe (s) + 3O2 (g) → 2Fe2O3 (s) If 4.8 moles of iron are sealed in a container with 5.3 moles of oxygen then: a. Iron is the limiting reactant because there are fewer moles of iron than oxygen b. Iron is the limiting reactant because there is not enough iron to react with the 5.3 moles of oxygen c. Oxygen is the limiting reactant because there are more moles of oxygen than iron d. Oxygen is the limiting reactant because there is not enough oxygen to react with the 4.8 moles of iron 9) Aspirin (C9H8O4, Mw = 180.154 g/mol) is prepared by the acetylation of salicylic acid (C7H6O3, Mw = 138.118 g/mol) according to the following balanced equation: C7H6O3 + (CH3CO)2O  C9H8O4 + CH3COOH If the yield of this reaction is 83%, what mass of salicylic acid would be needed to prepare 1000 g of aspirin? a. 766 g b. 636 g c. 1200 g d. 1300 g 10) For a given chemical reaction if we produce 862 kg when we run the reaction in the lab, and the percent yield is 92%, how much we will be the theoretical yield for the reaction? a. 936 kg b. 793 kg c. 7.9x104 kg d. 1.06x10-3 kg 11) An unknown compound is known to contain 40% Carbon, 6.7% Hydrogen, and 53.3% Oxygen. How many hydrogen atoms are there in the empirical formula for this compound? a. 1 b. 2 c. 3 d. 4 12) What is the molecular formula of a compound if the molar mass of the compound is found to be 264 gram/mol and the empirical formula is C2H4O? a. CHO b. C6H12O3 c. C2H4O d. C12H24O6 13) What is the percent by mass of carbon in dimethylsulfoxide (CH3)2SO? a. 30.7% b. 44.3% c. 15.4% d. 20.0% 14) A small glass of water contains 75.96 grams of water (Mw = 18 g/mol). How many moles of hydrogen atoms are in this glass of water? a. 5.08 x 1024 b. 2.54 x 1024 c. 4.22 d. 8.44 15) Consider the following conditions for the same gases in two different containers A and B: V = 6L and V A B = 3L T = -73C and T A B = 327C Which container experiences a greater pressure? a. The pressure is the same b. Container A c. Container B d. Can not be determined 16) A gas has a volume of 250.0 mL at 17°C and 3.00 atm pressure. To what volume the gas will expand under STP conditions? a. 771 mL b. 797 mL c. 78.4 mL d. 706 mL 17) How does gas particles respond to an increase in volume? a. Increase in kinetic energy and decrease in temperature b. No change in kinetic energy and increase in pressure c. Increase in kinetic energy and increase in temperature d. No change in kinetic energy and decrease in pressure 18) How many water molecules are there in 5.33 moles of water? a. 5.33 × 1023 b. 5.78 × 1025 c. 3.21 x 100 d. 7.12 × 1024 e. 3.21 × 1024 19) Consider the unbalanced chemical equation below. How many grams of CO2 can you produce from 5.33 × 1025 HCl particles? (assume excess Na2CO3) Na2CO3 + HCl → CO2 + NaCl + H2O a. 44.3 g b. 1.95 × 103 g c. 1.10 g d. 3.90 × 103 g e. 5.33 × 1024 g 20) What is the NET IONIC equation for the reaction between potassium bromide and mercury sulfate in aqueous solution? a. 2K+ (aq) + 2Br- (aq) + Hg2+ (aq) + SO42- (aq) → 2K+ (aq) + 2Br- (aq) + HgSO4 (s) b. 2Br- (aq) + Hg2+ (aq) → HgBr2 (s) c. 2K+ (aq) + SO42- (aq) → K2SO4 (s) d. Hg2+ (aq) + SO42- (aq) → HgSO4 (s) 21) You have a sodium hydroxide stock solution with a molarity of 6.0 M. You now take out 50 mL and want to make a 0.75 M solution. How much water to you need to add? a. 400 mL b. 300 mL c. 225 mL d. 175 mL e. 350 mL 22) Below are the heating curves for 4 different substances. Energy was put into the system at a constant rate. Which of the curves represent the substance with the largest value for Hvap? a. A b. B c. C d. D 23) Dimethoxyethane (DME) and ethylene glycol (EG) are two important organic solvents with similar structures. The boiling point of one is more than 100 ˚C higher than the other. What is the reason for this large difference in boiling points? a. DME has the higher boiling point because it forms hydrogen bonds b. EG has the higher boiling point because it’s less polar c. DME has the higher boiling point because there are more LDFs d. EG has the higher boiling point because it can form two hydrogen bonds 24) A given mass of gas in a rigid container is heated from 100°C to 500°C. Which of the following responses best describes what will happen to the pressure of the gas? a. The pressure will decrease by a factor of five. b. The pressure will increase by a factor of five. c. The pressure will increase by a factor of about two. d. The pressure will increase by a factor of about eight. e. The pressure will increase by a factor of about twenty-five. 25) An unknown gas effuses 1.73 times faster than krypton. What is the molar mass of the gas? a. 28.0 g/mol b. 48.4 g/mol c. 110 g/mol d. 251 g/mol 26) What is the kinetic energy of a ball with a mass of 5 kg rolling at 10 m/s? (HINT: 1J= kg•m2•s-2) a. 5.0 J b. 250 J c. 25 J d. 50 J 27) How many moles of ions are there in 20 g of magnesium phosphate, Mg3(PO4)2? a. 5.0 moles b. 0.038 moles c. 0.19 moles d. 0.38 moles 28) How many H atoms are there in a sample of C5H10 that contains 6.59 x 1026 C atoms a. 1.31 x 1027 H atoms b. 3.29 x 1026 H atoms c. 2.19 x 103 H atoms d. 1.09 x 103 H atoms 29) When C3H8 hydrocarbon combustion reaction occurs the products are: a. 4CO2 + 3H2O b. 3CO2 + 4H2O c. 2CO2 + 3H2O d. 3CO + 4H2O 30) Which of the following represent a dissolution reaction? a. NaCl (aq) + AgNO3 (aq) → AgCl (s) + NaNO3 (aq) b. NaCl (s) → Na+ (aq) + Cl- (aq) c. CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (g) d. N2 (g) + 2O2 (g) → 2NO2 (g) 31) You have 500 mL of a 1.25 M Pb(NO3)2 solution. How much solid sodium chloride do you need to add to react all of the lead? ? (HINT: react lead (II) nitrate with sodium chloride) a. 54.6 g b. 44.3 g c. 146 g d. 73.1 g This page was intentionally left blank This page was intentionally left blank City University of New York GenChem I 12 Spring 2020 Exam 3A City University of New York General Chemistry I: Exam Appendix Constants Equations R = 8.314 J/mol-K R = 0.082 L-atm/mol-K h = 6.626 x 10-34 J-s c = 3.00 x 108 m/s NA = 6.022 x 1023 particles/mole E = (-2.18x10-18J) Z2/n2 E = hc/λ E = mc2 KE = (1/2)mvo2 KE = (3/2)nRT PV = nRT T(K) = T(oC) + 273 Solubility Rules • all ammonium salts and group 1A salts are soluble • all nitrates are soluble • most chlorides, bromides, and iodides are soluble except silver, mercury, and lead • most sulfates are soluble except calcium (slightly soluble), barium, strontium, and lead • all chlorates and perchlorates are soluble • all acetates (C2H3O2-) are soluble • phosphates are insoluble (except ammonium and Group 1A) • carbonates are insoluble (except ammonium and Group 1A) • chromates (CrO42-) are insoluble (except for ammonium, Group 1A, magnesium) • hydroxides are insoluble (except ammonium, Group 1A, barium, strontium, calcium) • sulfides are insoluble (except ammonium, Group 1A, magnesium, barium, strontium, calcium) Electromagnetic Spectrum Molecular Orbital Arrangements σ2p* π2p* σ2p π2p σ2s* σ2s B2 C2 N2 σ2p* π2p* π2p σ2p σ2s* σ2s O2 F2 GenChem I 13 Spring 2020 Exam 3A