Question

14. Styrene oxide is a fairly simple aromatic organic compound that has a pleasant odor and is often used in the perfume industry. If 2.07 g of the compound is vaporized completely into a closed 1.04 L flask at 435 °C, the pressure in the flask is found to be 735 torr. Calculate the formula weight of styrene oxide. 15. a. A sample of dichloroethane, a dry cleaning solvent, is vaporized into a 266.4 mL flask at 99.8 °C. Some of the sample leaves the flask through a pinhole through the stopper until the pressure in the flask is the same as the outside pressure. A barometer shows the pressure to be 745.3 torr. When the flask is cooled, the mass of dichloroethane in the flask is measured to be 0.8447 g. Calculate the formula weight of dichloroethane. b. Is the formula of dichloroethane CH2Cl2, C2H4Cl2, or C&HgCl2? 5. Diborane, B2H, is a highly explosive compound formed by the reaction 3 NaBH4(s) + 4 BF3(g) - 2 B2H6(g) + 3 NaBF4(s) What mass of NaBH4 is required to give 1.00 L of diborane at 0.0 °C and 1.00 atm? For the reaction, as written: Sg(s) + 8 O2(g) - 8 SO2(g) AH = -2368 kJ a. How much heat is evolved when 25 moles of sulfur is burned in excess oxygen? b. How much heat is evolved when 275 grams of sulfur is burned in excess oxygen? How much heat is evolved when 150.0 grams of sulfur dioxide is produced?

Answer 1

let molecular yurs of styrene oxide is 59.*** W = 2.079 from idal gas quels V = 1.04 L PvIRRT T = 435°C £435+273)K PV 2 RT. 708 K ORT P 2 73 store Pv 0-082 2-678 8314x708K 1.04 752 235 35 360 iM = 119.62 After cooling 09 @ W ChuCl = 0.8447 V = 266.4mL T = 99.8°C =g9-8-273 2372.8K P = 745.3 ten 248.3 760 us atm عطمنممنههطل then form idal gesel PV=nRT 24 ne po 348.3 x<0-2664 760 0.0821 372-8 let molar then 28.54 X10-3 mans of bem con then = 98.9 0- 8497 8.sux10 3

② 244022 2 B H 6 (g) + 3NaBFq (s) (16 3Na BM& & 4B F2 (g) ginen PV = nRT Pr - ory a 2 PVM = 1x18 28 M VB266 = 12 sem idel gens eft T = 273K P = latin Mbaho = 28 g/mol. o 2 RT = 0.88214273 = 1.25 9 Mono = 35 mole to no mole of Na Buq (s) required to produce 35 mole of Behb = 3 x 35 Na Bh4 = 2x35 x 38 = 1995g S8(6+ 808) 850₂ (9) jan 2-2 368 kg (a) for n = 25 mole - enegy evole = 258 2368 kJ (6) Wsz z 275 n.se = 275 = 1-6742 mole enegy evoked = 1:8742%2368 kg =2543 Asig Wso = isog suy = 150/4=2.34 Energy Cheut) nelered = 82.34 x 256. AT - Gariskt 259200K