Old Exam 1 with Answer Key - General Chemistry I | CHE 1103, Exams of Chemistry

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1. Abox is 252.56 cm wide, 19.23 cm deep and 6: 10* g. What is the density of the box? 2.5 ¥ \0.23 xe 900 = AISUS. 4712. cm3 ) 0.7938 gfem 5 b) 3.160 x 10” g/cm’ 3.01 «10% a |.2v0g om? c) 1.255 x 10° g/cm Sores +. Cy 4 , @)) 1.260 g/icm* 3\ O08. 1372 Cy) e) 3.200 x 104 g/cm? 2. ~ is the mass number of a copper atom with 36 neutrons? ae IC=IA=P Mass = Waepry 1 a) 63.55 —b) 36 c) 29 d) 63 @/Jes . - ue 3. What answer should be reported with the correct number of significant figures for the following calculation? (249.362 + 41) / 63.498 PA0.2W2. [V3.44€ = Aly %~ @) 46 4.57 c) 4.573 d) 4.5728 e) 4.57277 wy. A pure substance was found to contain only hydrogen a Cl ified 25 clon oe 2. PROBLEMS(8 points each). d A sample of magnetic iron oxide, Fe304, reacts completely with hydrogen at red heat. The water vapor formed by the reaction Fes0, + 4H2 —> 3Fe + 4H,0 ls condensed and found to weigh 28.15 g. How many grams of Fe30, reacted? _23\ 65 26.10 FoD. lola) . \molabr a4qFeaDa . oq 8 0.7875 a Laci are 2a a AS } b) 3.150g Geral AuLys0 \woDIE c) 2.363 g d)} 90.45 g e) 8.064g y6. How many moles of dinitrogen trioxide contain 2.55 x 10” oxygen atoms? Le ede .41 mol " <4 b) 4.23mol 25x \0°F0atpmas, mol 0 = 49S M0 Ni 022003 aomcn eS 787 mol WD22AD” atOMSD | | Dl Nada e) 2.82 mol Amo\ Oats 7. ‘wo samples of potassium iodide are decomposed into their constituent elements. The first sample produced 13.0 g of potassium and 42.3 g of iodine. If the second sample produced 24.4 kg of potassium, how many kg of iodine were produce? JA, Ki . +EG = 24-4009 K a)13.3kg b)22.5kg (c)¥94kg d)44.4kg ©) 92.4kg BOQ . | “1A 29% S4uibal leq