Chemistry Exam Questions: Equations and Constants - Prof. Sara L. Mcintosh, Exams of Chemistry

Download Chemistry Exam Questions: Equations and Constants - Prof. Sara L. Mcintosh and more Exams Chemistry in PDF only on Docsity! Equations and Constants NA = 6.022 x 1023 R = 8.314 J/mol K = 0.08206 L atm/mol K me = 9.10939 x 10-31kg c = 2.998 x 108 m/sec h = 6.626 x 10-34 J s RRydberg = 1.096776 x 107 m-1 1 atm = 760 mmHg = 760 torr = 1.01325 bar = 1.01325 x 105 Pa PV = nRT PA = χA PTotal MM RT urms 3  a acbb x 2 42   q = mcΔT ΔE = q + w dw = -pdV ΔH = ΔE + PΔV ΔHorxn = ΣmΔHof (products) – ΣnΔHof (reactants) E = hν c = νλ mu h   h p  En = -(2.18 x 10-18J) 1/n2 (Hydrogen Atom) KE(electron) = hν – Ф KE = ½mu2          2 2 2 1 111 nn RRydberg  (where n2 > n1) pH = -log[H+] pOH = -log[OH-] pH + pOH = 14 Ka·Kb = Kw Kw = 1.0 x 10-14 (at 25oC) M1V1 = M2V2 Table of Electronegativities H 2.1 Li 1.0 Be 1.5 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0 K 0.8 Ca 1.0 Sc 1.3 Ti 1.5 V 1.6 Cr 1.6 Mn 1.5 Fe 1.8 Co 1.9 Ni 1.9 Cu 1.9 Zn 1.6 Ga 1.6 Ge 1.8 As 2.0 Se 2.4 Br 2.8 EXAM 2 Spring 2010 Chemistry 1100 50 Minutes 25 Questions 4 Points Each 1. A certain gas has a density of 2.23 g·L–1 at 0 °C and 760 mmHg. Its molar mass (g/mole) is (A) 5.00 (B) 50.0 (C) 49.0 (D) 51.0 2. Which gas, present in the same closed system, has the greatest average kinetic energy at a given temperature? (A) hydrogen (B) neon (C) carbon dioxide (D) None; the average kinetic energy is the same for each gas. 3. The Kelvin temperature of one liter of gas is doubled and its pressure is tripled, volume will then be (A) 1/6 L (B) 2 / 3 L (C) 3/2 L (D) 6 L 4. A 10.0 cm3 container of helium is sealed at 22.0 °C and 1.00 atm pressure. What pressure would be exerted by the helium if the container were heated to 220 °C? (A) 10.0 atm (C) 1.67 atm (B) 2.01 atm (D) 1.08 atm 12. A common laboratory reaction is the neutralization of an acid with a base. When 50.0 mL of 0.500 M HCl at 25.0°C is added to 50.0 mL of 0.500 M NaOH at 25.0°C in a coffee cup calorimeter, the temperature of the mixture rises to 28.2°C. What is the heat of reaction per mole of acid? Assume the mixture has a specific heat capacity of 4.18 J/(g·K) and that the densities of the reactant solutions are both 1.00 g/mL. (A) 670 J (B) 27 kJ (C) > 100 kJ (D) 54 kJ (E) 1300 J 13. The heats of formation, H f 0 in are shown in the table. What is H in kJ for the reaction 2C2H2 + 5O2(g)  4CO2(g) + 2H2O(g) H = ? Compound H f 0 C2H2(g) +227 H2O(g) –242 CO2(g) –393 (A) –4 393– 2  242 + 227 (B) –4 393– 2 242–227 (C) –4  393– 2  242– 2  227 (D) –4 393– 2  242+ 2  227 14. The heat of combustion for one mole of carbon is 410 kJ. C(s) + O2(g)  CO2(g) The reaction is exothermic to the right. How many kJ of heat would be liberated on the complete combustion of 60 g of carbon? Atomic Molar Mass C 12.0 g·mol–1 (A) 5  410 kJ (C) 44  410 kJ (B) 12  410 kJ (D) 60  410 kJ 15. What is the value of H for this reaction? 3H2(g) + O3(g)  3H2O(l) H2(g) + 1/2O2(g)  H2O(l) H = –286 kJ 3O2(g)  2O3(g) H = +271 kJ (A) –15 kJ (D) –995 kJ (B) –558 kJ (E) –1130 kJ (C) –722 kJ 16. A 10.0 g sample of silver is heated to 100.0 °C and then added to 20.0 g of water at 23.0 °C in an insulated calorimeter. At thermal equilibrium the temperature of the system was measured as 25.0 °C. What is the specific heat of silver? Data for Water specific heat(water) 4.2 J·g–1·°C–1 (A) 0.11 J/g·K (B) 17 J/g·K (C) 34 J/g·K (D) 0.22 J/g·K 17. Given these equations SO2(g)  O2(g) + S(s) H = +300 kJ 2SO2(g) + O2(g)  2SO3(g) H = –200 kJ calculate the heat of formation of SO3(g). (A) –500 kJ·mol–1 (B) –400 kJ·mol –1 (C) +100 kJ·mol–1 (D) +200kJ·mol–1 18. What is the energy of the photon needed to ionize a hydrogen atom from the n = 5 level? En = -(2.18 x 10-18J)/n2 (c = 2.998 x 108 m/s, h = 6.626 x 10-34 J·s ) (A) 8.72 x 10 -20 J (B) 9.11 x 10-9 J (C) 3.97 x 10-26 J (D) 4.36 x 10-19 J (E) 2.18 x 10-18 J