Chemistry Exam Notes: Conversions, Formulas, and Reactions, Exams of Chemistry

Download Chemistry Exam Notes: Conversions, Formulas, and Reactions and more Exams Chemistry in PDF only on Docsity! Convert 3.21 x 10-5 = negative exponent = smaller than 1, move decimal 5 Chem 103 Module 1 Exams Questions and Answer 12 Answered Questions MODULE 1 EXAM - = 8.453 x 102 1. 24.6 grams =? kg 2. 6.3 ft =? inches please always use the correct units in your final answer Question 3 31 y Question 8 = 70Ga +3 31 protons = Ga31, 39 neutrons = 70Ga31, 28 electrons = (+31 - 28 = +3) 1. PF5 - binary molecular = phosphorus pentafluoride 2. Al2(CO3)3 - nonbinary ionic = aluminum carbonate - 2 2. Manganese (IV) acetate - Mn+4, C2H3O -1 = Mn(C2H3O2)4 - MODULE 2 EXAM H2CrO4 - nonbinary acid = chromic acid Question 2 Click this link to access the Periodic Table. This may be helpful throughout the exam. Show the calculation of the number of moles in the given amount of the following substances. Report your answerto 3 significant figures. 1. 13.0 grams of (NH,),CO; 2. 16.0 grams of C;H.NO.Br Question 3 Click this link to access the Periodic Table. This may be helpful throughout the exam. Show the calculation of the number of grams in the given amount of the following substances. Report your answer to 1 place after the decimal. 1. 1.20 moles of (NH,),CO; 2. 1.04 moles of C,H.NO,Br Question 4 Click this link to access the Periodic Table. This may be helpful throughout the exam. Na2HAsO3: Na is metal in group I = +1 (total is +2), H = +1, each O is -2 H3AsO4: H is +1 (total is +3), each O is -2 (total is -8), so As is +5 KBrO3: K is metal in group I = +1, each O is -2 (total is -6), so Br is +5 2KMnO4 + 1 KI + 1 H2O → 1 KIO3 + 2MnO2 + 2KOH KMnO4 + KI + H2O → KIO3 + MnO2 + KOH KMnO4: K is metal in group I = +1, each O is -2 (total is -8), so Mn is +7 → 3. H2 + NiO → Ni + H2O = Single Replacement, Hydrogen displaces KIO3: K is metal in group I = +1, each O is -2 (total is -6), so I is +5 2 C6H6 + 15 O2 → 12 CO2 + 6 H2O 1.582 mole CO2 x (12.01 + 2 x 16.00) = 69.6 g CO2 → → = 1.58 mole CO2 MnO2: Each O is -2 (total is -4), so Mn is +4 1. - (mwarn H2O x cwarn H2O x ∆twarn H2O) = (mcool H2O x ccool H2O x ∆tcool H2O) MODULE 3 EXAM Question 1 740 ml/1000 = 0.740 liters = Vi 710 mm/760 = 0.934 atm = Pi 460 ml/1000 = 0.460 liters = Vf 1.20 atm = Pf 35oC + 273 = 308oK = Ti (0.934) x (0.740) / 308 = (1.20) x (0.460) / Tf Tf = 246 oK ΔHrxn = 2(+74.6) + 3(0) + 2(-110.5) + 4(-285.8) = - 1215.0 kJ/mole 710 mm/760 = 0.934 atm = P 35oC + 273 = 308oK 2 C6H6 (g) + 15 O2 (g) → 12 CO2 (g) + 6 H2O (g) 25.5 grams 37.75 liters ↓ ↑ by V = nRT / P Question 9 nN2 = gN2 / (MWN2) = 7.60 g / 28.02 = 0.2712 mol nO2 = gO2 / (MWO2) = 8.40 g / 32.00 = 0.2625 mol → (MW = 78) (MW = 32) (MW = 44) (MW = 18) 0.632 mole = n R = 0.0821 XO2 = 0.2625 / (0.2712 + 0.2625) = 0.4918 Question 10 (rN2 /runknown)2 = MWunknown / MWCO2 (1.83/1)2 = MWunknown / 44.01 MWunknown = (1.83)2 x 44.01 Fe26 = 26 electrons = 1s2 2s2 2p6 3s2 3p6 4s2 3d6 MODULE 4 EXAM .e tc.) .e tc.) S16 = 16 electrons = 1s2 2s2 2p6 3s2 3p4 XN2 = 0.2712 / (0.2712 + 0.2625) = 0.5082 Question 8 Click this link to access the Periodic Table.This may be helpful throughout the exam. 1. List and explain which of the following atoms forms a positive ion with more difficulty. Sn orl 2. List and explain which of the following is the smaller atom. Sn or Te ls Question 9 Click this link to access the Periodic Table.This may be helpful throughout the exam. On a piece of scratch paper, draw the orbital configuration of the C, atom and use it to draw the Lewis structure for the C, atom. Then choose the correct Lewis structure for C, from the options listed below. A) iC: B) :C. C):c. D):c: E) Cc 9  tr tr ↑↓ ↑↓ ↑↓↑↓↑↓ ↑↓ ↑↓↑↓↑↓ ↑↓ ↑↓↑↓↑↓↑↓↑↓↑↓ ↑↑↑ MODULE 5 EXAM → Se-2 gain 2e Se34 (nonmetal = gain electrons) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4 3 3 H-C bond electronegativity difference = 2.5 - 2.1 = 0.4 <0.5 NH3 (Hydrogen Bonding) Question 1 Not yet graded / 10 pts Question 2 Not yet graded / 10 pts Question 3 Not yet graded / 10 pts Please note in this question you are not being asked to list BPs but the compounds in a list from highest to lowest BP on the basis of the type of compound. forms ions in solution. Sugar (C6H12O6) is a molecular compound but does not FP: Al2(SO4)3 < GaCl3 < MgCl2 < NaI Question 4 Not yet graded / 10 pts - - → - → → - → - Question 5 Not yet graded / 10 pts molality = (gsolute / MW) / (gsolvent / 1000) Question 6 Not yet graded / 10 pts Molarity = (gsolute / MW) / (mlsolvent / 1000) Question 7 Not yet graded / 10 pts molality = ∆tf / Kf = 1.35 / 1.86 = 0.726 m molality = (gsolute / MW) / (gsolvent / 1000) 2. Convert 3.21 x 10-5 = negative exponent = smaller than 1, move decimal 5 FINAL EXAM - = 8.453 x 102 ∆tf = Kf x m 3. 18oF - 32 ÷ 1.8 = -7.8 + 273 = 265.2 oK oF → oC → oK → → f 2 6 f f 2 f 2 6 f f 2 1. %Al = 2 x 26.98/342.17 x 100 = 15.77% %S = 3 x 32.07/342.17 2 C2H6 (g) + 5 O2 (g) → 4 CO (g) + 6 H2O (l) ΔH 0 C H (g) = -84.0 kJ/mole, ΔH 0 CO (g) = -110.5 kJ/mole, ΔH 0 H O (l) = -285.8 ΔHrxn = 2(+84.0) + 5(0) + 4(-110.5) + 6(-285.8) = - 1988.8 kJ/mole → kJ/mole kJ/mole 1. List and explain which of the following is the smaller atom.C or N 2. List and explain which of the following atoms holds its valence electronsmore tightly. Br or | CH4 has all nonpolar bonds which makes it Nonpolar and since it is Nonpolar → Br-1 gain 1e Br35 (nonmetal = gain electrons) 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5 Question 11 Question 12 Click this link to access the Periodic Table. This may be helpful throughout the exam.