CHE 131 Exam 1 Fall 2024 PDF

CHE 131, Exam 1 Fall 2024 Form 1A CHE 131 Exam 1 Fall 2024 Version 1A Directions: 1. Do not open this exam until told to do so. 2. Place your ID (face up), pencils, eraser...

CHE 131, Exam 1 Fall 2024 Form 1A CHE 131 Exam 1 Fall 2024 Version 1A Directions: 1. Do not open this exam until told to do so. 2. Place your ID (face up), pencils, erasers, and a scientific calculator at your desk. 3. Place all other items out of sight at the side of the room and/or under your seat. 4. Verify that the Form number (1A, 2B, 3C, or 4D) on your Scantron and your exam packet match. a. On your Scantron, write and bubble in: i. LAST NAME ii. FIRST NAME iii. IDENTIFICATION NUMBER 5. Under Course Name, write “CHE 131”. 6. All Scantron forms must be submitted by 9:35 pm. No extra time will be given. 7. All answers must be entered on the Scantron answer sheet, which you must turn in before leaving. Scantrons will not be returned; record your answers in the space provided in the exam packet next to each question for comparison with the answer keys when they are posted on Brightspace. Use blank spaces between questions, backs of pages, and extra sheets for scratch work and calculations. 8. Once you open the exam, double check that you have all exam pages, including a Periodic Table and a sheet of useful conversions, constants, and equations. Page numbers and total number of pages are at the bottom of each page. If you are missing pages, request a new copy of the exam. 9. During the exam you will be asked to show your ID and sign in on an attendance sheet. 10. General Chemistry Policies: a. Possession of cell phones, other digital devices, or any unauthorized materials during the exam will result in a grade of 0 on this exam, a report to Academic Judiciary, and a possible grade of F for the course. b. If you do not have an ID to verify your identity, you must see Dr. Ivarson the day after the exam and show her a valid ID. 1 CHE 131, Exam 1 Fall 2024 Form 1A Blank Page 2  CHE 131, Exam 1 Fall 2024 Form 1A Conversion Factors Mass Temperature Pressure 1 lb = 453.59237 g TC = 5/9(TF – 32) 1 Pa = 1 N m-2 1 lb = 16 oz TK = TC + 273 K = 1 kg m-1 s-1 TF = (9/5)TC + 32 1 atm = 101.325 kPa Length = 760 mmHg 1 km = 0.62137 miles Energy =760 Torr 1 Å = 10-10 m 1 Joule = 1 kg m2 s-2 = 14.70 lb/in2 1 in = 2.54 cm = 0.2390 calorie 1 bar = 1 x 105 Pa =1Cx1V Volume = 1 Pa m3 1 L = 1.056710 qt 1 L atm = 101.325 J 1 gallon = 4 quarts 1 Cal = 1000 cal Physical and Chemical Constants electron mass = 9.109 × 10–31 kg kB = 1.381 x 10-23 J K-1 F = 96,485 C mol-1 proton mass = 1.672621 × 10–27 kg RH = 2.178 x 10-18 J 1 Ci = 3.70 x 10-10 d/s –27 neutron mass = 1.674927 × 10 kg 1 MeV = 1.6022 x 10-13 J ke = 8.9875 x 109 N m2 C-2 electron charge = 1.602 × 10–19 C 1 amu = 1.66054 x 10-27 kg p = 3.141592654 23 NA = 6.002 x 10 mol 1 amu = 931.5 MeV R = 0.08206 L atm mol-1 K-1 = 8.314 J K-1 mol-1 c = 2.988 x 108 m s-1 h = 6.626 x 10-34 J s Properties of Water Heat Capacities J g-1 K-1 J mol-1 K-1 r = 1.00 g//mL = 1.00 g/cm3 Water (steam) 2.080 37.47 DHfus = 6.01 kJ/mol Water (liquid, 25°C) 4.184 75.327 DHvap = 40.68 kJ/mol Water (ice, -10°C) 2.050 38.09 Kw = 1.00 x 10-14 at 298 K Standard Thermodynamic Conditions 1 atm 1M 298 K STP: 1 bar, 0°C Equations DE = q + w c = ln PV = nRT PA = XA x Ptotal DH = DE + PDV @ constant pressure E = hn 𝑛! 𝑎 𝑛" !𝑃 + ! ' (𝑉 − 𝑛𝑏) = 𝑛𝑅𝑇 𝑋" = 𝑉 𝑛#$#%& w = -PextDV E= '( 𝑃* 𝑉* 𝑃! 𝑉! 𝑘𝑞* 𝑞! ) = 𝐹= 𝑛* 𝑇* 𝑛! 𝑇! 𝑟! DH°rxn = SmDH°f (products) - SnDH°f (reactants) q = mCsDT 3𝑅𝑇 𝑐+,- = 5 𝑀𝑀 DH°rxn = SDH°reactant bonds broken - SDH°product bonds formed 𝑢" 𝑀𝑀. =5 𝑢. 𝑀𝑀" 3 CHE 131, Exam 1 Fall 2024 Form 1A 4  CHE 131, Exam 1 Fall 2024 Form 1A MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The result of (4.980 – 1.8621) × 2.5630 is properly written as 1) A) 7.991. B) 0.207. C) 7.9912 D) 0.2074. E) 8.000. 2) Which formula/name pair is incorrect? 2) A) Mn(NO3 )2 manganese(II) nitrate B) Mg(NO3 )2 magnesium nitrate C) Mg N 3 2 magnesium nitrite D) Mn(NO2 )2 manganese(II) nitrite E) Mg(MnO4 )2 magnesium permanganate 3) Which of the following samples contains the greatest number of atoms ? 3) A) 150 g of NaCl B) 50 g of Li2 O C) 40 g of C2 H2 D) 200 g of Fe2 O3 E) 100 g of CO2 4) Which of the following two atoms are isotopes? 4) 24 12 12 13 A) Mg and C B) C and C 12 6 6 6 40 40 35 80 C) Ar and Ca D) Cl and Br 18 20 17 35 5) A compound of bromine and fluorine is used to make UF6 , which is an important 5) chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula. A) Br2 F3 B) Br3 F C) BrF3 D) BrF2 E) BrF 6) Read the length of the metal bar with the correct number of significant figures. 6) A) 15.0 cm B) 20 cm C) 15.000 cm D) 15.00 cm E) 15 cm 5  CHE 131, Exam 1 Fall 2024 Form 1A 7) The following measurements were made by a group of students using the same balance and a 7) 30.00 gram weight. Trial Mass (g) 1 23.96 2 24.01 3 23.98 4 23.97 The data would be considered: I) accurate and precise II) accurate but not precise III) precise but not accurate IV) neither precise nor accurate V) evidence of a systematic error VI) evidence of large random errors A) I only B) II and VI C) III and V D) IV and VI E) IV, V, VI 8) The formula of nitrobenzene is C6 H5 NO2. The molecular weight of this compound is ________ 8) amu. A) 123.11 B) 43.03 C) 3.06 D) 107.11 E) 109.10 9) A wooden object has a mass of 10.782 g and occupies a volume of 13.72 mL. What is the density of 9) the object determined to an appropriate number of significant figures? A) 8 × 10-1 g/mL B) 7.9 × 10-1 g/mL C) 7.86 × 10-1 g/mL D) 7.859 × 10-1 g/mL E) 7.8586 × 10-1 g/mL 10) In the combustion analysis of 0.600 g of C6 H12O6, what mass of H2 O will be produced? 10) A) 0.147 g B) 0.360 g C) 1.240g D) 0.060 g E) 0.880 g 11) The mass of a sample is 550 milligrams. Which of the following expresses that mass in 11) kilograms? A) 5.5 × 10–4 kg B) 5.5 × 105 kg C) 5.5 × 108 kg D) 5.5 × 10–6 kg E) 5.5 × 10–1 kg 12) A small amount of salt dissolved in water is an example of a ________. 12) A) compound B) homogeneous mixture C) heterogeneous mixture D) pure substance E) solid 6  CHE 131, Exam 1 Fall 2024 Form 1A 13) There are ________ protons, ________ neutrons, and ________ electrons in 238U+5. 13) A) 92, 92, 87 B) 92, 146, 87 C) 146, 92, 92 D) 146, 92, 97 E) 92, 146, 92 14) Calculate the percentage by mass of oxygen in Pb(NO3 )2. 14) A) 19.3 B) 33.4 C) 29.0 D) 9.7 E) 14.5 15) Household sugar, sucrose, has the molecular formula C12H 22O 11. What is the percent of 15) carbon in sucrose, by mass? A) 26.7% B) 33.3% C) 42.1% D) 41.4% E) 52.8% 16) The correct name for HNO2 is ________. 16) A) pernitric acid B) nitrous acid C) nitric acid D) hydrogen nitrate E) hyponitrous acid 17) Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % 17) O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound? A) CH5 O B) C 5 H 12O 5 C) C 5 H 10O 5 D) C 4 H 8 O 6 E) C 6 H 12O 4 18) The element X has three naturally occurring isotopes. The masses (amu) and % abundances of the 18) isotopes are given in the table below. The average atomic mass of the element is ________ amu. Isotope Abundance Mass 221X 74.22 220.9 220X 12.78 220.0 218X 13.00 218.1 A) 218.5 B) 221.0 C) 220.4 D) 220.42 E) 219.7 19) Atomic nuclei are made of protons and neutrons. Which of the following substance has the 19) smallest number of protons? A) 1.2 mols of C2 H2 B) 20 grames of NaCl C) 0.6 moles of Oxygen gas D) 20 grams of Fe2 O3 E) 20 grames of Pb 7  CHE 131, Exam 1 Fall 2024 Form 1A 20) What is the mass percentage of H in a uniform mixure of 1 mole of C2 H6 and 1 mol of 20) N H3 ? A) 29.8% B) 20.0% C) 37.6% D) 17.6% E) 19.1% 21) Aluminum oxide, Al2 O 3 , is used as a filler for paints and varnishes as well as in the 21) manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2 O 3. A) 1.105 mol B) 0.4207 mol C) 2.146 mol D) 2.377 mol E) 0.4660 mol 22) Combustion analysis of 2.400 g of an unknown compound containing carbon, hydrogen, and 22) oxygen produced 4.171 g of CO2 and 2.268 g of H2 O. What is the empirical formula of the compound? A) C2 H5 O2 B) C3 H8 O2 C) C2 H5 O D) C2 H10O3 E) C6 H16O4 23) How many significant figures should be retained in the result of the following calculation? 23) 12.00000 × 0.9893 + 13.00335 × 0.0107 A) 2 B) 3 C) 4 D) 5 E) 6 24) Which compounds do not have the same empirical formula? 24) A) C2 H5 COOCH3 , CH3 CHO B) C2 H4, C3 H6 C) C2 H2, C6 H6 D) CO, CO2 E) C2 H4 O2 , C6 H12O6 25) One million oxygen gas contain ________ mol of oxygen atoms. 25) A) 3.32 × 10-18 B) 6.0 2× 1023 C) 1.66× 10-18 D) 3.32 E) 1.0 × 106 26) Which of the following compound contains the most number of anions ? 26) A) 1 mol of Li2 O B) 1 mol of CO2 C) 1 mol of C6 H6 D) 1 mol of CaCl2 E) 1 mol of Na3 P 8 CHE 131, Exam 1 Fall 2024 Form 1A Blank Page 9 CHE 131, Exam 1 Fall 2024 Form 1A Blank Page 10  CHE 131, Exam 1 Fall 2024 Form 1A Answer Key 1) A 2) C 3) E 4) B 5) C 6) A 7) C 8) A 9) D 10) B 11) A 12) B 13) B 14) C 15) C 16) B 17) C 18) C 19) E 20) E 21) E 22) B 23) C 24) D 25) A 26) D 11