Chemistry 400: General Chemistry Miller Exam II November 4, 2015 Approximately 150 points

Size: px

Start display at page:

Download "Chemistry 400: General Chemistry Miller Exam II November 4, 2015 Approximately 150 points"

Brent Rich
5 years ago
Views:

Chemistry 400: General Chemistry Name: Miller Exam II November 4, 2015 Approximately 150 points Please answer each of the following questions to the best of your ability.

1 Chemistry 400: General Chemistry Name: Miller Exam II November 4, 2015 Approximately 150 points Please answer each of the following questions to the best of your ability. If you wish to receive partial credit, please show your work. For multiple choice, there is no partial credit (unless otherwise noted) and there is only one correct answer. For multiple choice, please clearly mark the correct answer. Good luck! New equation for your equation sheet: w = -P DV 1 L atm = J I. Multiple choice are 4 points. Each blank is worth two points. 1. : anything that has the capacity to do work 2. : a force acting over a distance 3. : the measure of the amount of thermal energy within a sample of matter 4. Which of the following scenarios has the lowest energy? A. a hydrogen atom with an electron in the n = 1 principal energy level B. a hydrogen atom with an electron in the n = 2 principal energy level C. a hydrogen atom with an electron in the n = 3 principal energy level D. a hydrogen atom with an electron in the n = 4 principal energy level 5. Which of these could be the values of l and m l for an electron in a 4p sublevel: A. l = 0, m l = 0 B. l = 1, m l = 1 C. l = 0, m l = 1 D. l = 1, m l = 2 E. l = 2, m l = 2 6. Wave-like property of electromagnetic radiation: Besides the amplitude of an electromagnetic wave, an electromagnetic wave can be characterized by one other variable, either or. 7. Particle-like properties of an electron: An electron, a particle, has two properties of any particle: and. 8. Wave-like property of an electron: Because an electron has so little mass, it also exhibits wave-like properties, such as wavelength. Calculate the wavelength of an electron traveling at 5.0x10 6 m/s. (6 points) 1 28 points

2 9. If gas A (molar mass = g/mol) and gas B (molar mass = g/mol) are in different containers of the same volume at the same temperature and have equal numbers of moles, what is the relationship between their pressures: A. P A > P B B. P A < P B C. P A = P B D. There is not enough information to tell the relationship. 10. Which of these substances has the highest heat capacity on a per mole basis (not a per gram basis)? A. Aluminum B. Hydrogen gas C. Gold D. Octane E. Carbon dioxide 11. Using the graph below for which T = 0 C, determine the gas that has the lowest molar mass. A. A B. B C. C D. D E. All of the gases have the same molar mass at 0 C. II. Free Response 1. A 150 gram block of iron is heated to 225 C and then is dropped into a coffee cup calorimeter containing 250 g of water at 25.0 C. What is the final temperature of the system? (Assume all heat from the iron is transferred to the water). (10 points) Specific heat capacity of iron = J/g C 2 22 points

2. How much work in Joules does it take to pump a bicycle pump if the initial volume is 3 L, the final volume is 0.2 L, and you apply 5 atmospheres of pressure? (8 points) 1 L atm = 101.

3 2. How much work in Joules does it take to pump a bicycle pump if the initial volume is 3 L, the final volume is 0.2 L, and you apply 5 atmospheres of pressure? (8 points) 1 L atm = J 5 atm 3 L 0.2 L 3. Write out the electron configuration for each of the following chemical species: (10 points) Full electron configuration: A. Cl atom Noble gas core electron configuration: B. Fe 2+ ion 4. Circle the chemical species with the larger radius and explain why: A. sodium atom or potassium atom (8 points) B. chlorine atom or sulfur atom (8 points) C. F ion or O 2 ion (8 points) 3 42 points

5. The Helium-Neon (HeNe) laser pictured below emits light at a wavelength of 633.8 nm and an energy of 10 mj/sec. Please determine the following for this laser: A.

4 5. The Helium-Neon (HeNe) laser pictured below emits light at a wavelength of nm and an energy of 10 mj/sec. Please determine the following for this laser: A. The frequency (4 points) B. The energy of one photon (4 points) C. The energy of the light in kj/mol (kj per mol of photons) (4 points) D. The number of photons emitted in 5 seconds. (6 points) 4 18 points

5 6. Calculate the temperature of 2.20 moles of gas occupying 3.50 L at 3.30 atm. (6 points) 7. A flask at room temperature contains exactly equal amounts (in moles) of nitrogen and xenon. (3 points each) A. Which of the two gases exerts more pressure? B. The molecules or atoms of which gas have the greater velocity? C. The molecules or atoms of which gas have the greater average kinetic energy? D. If a small hole were opened in the flask, which gas would effuse more quickly? 18 points 5

6 8. In Game of Thrones, dragons breathe fire. How could dragons breathe fire? It would definitely involve some thermochemistry. As dragons digest their food, there is a build up of the gas methane, CH 4, that in humans would become flatulence. However, let's suppose that dragons store this methane in a separate sac that connects with their throats such that they can exhale the methane. That methane could then burn to produce fire: CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(g) A. What is the change in the enthalpy of reaction, ΔH rxn, for the above reaction? (6 points) B. Draw a reaction Energy Diagram for the above reaction. Label the x- and y-axes, reactants and products, and ΔH rxn. (6 points) C. What would the volume of the storage sac for the methane have to be if a "breath of fire" had an energy of -25,000 kj? Assume that the pressure is 1 atm and the temperature is 37 C. (10 points) D. Is this a realistic volume given that a dragon has a typical height of 10 meters and a width of 5 meters? Show calculations to justify your answer. The volume of a cube equals length cubed. (4 points) 6 26 points

7 Chemistry 400 Conversions and Equations 1 L = qt 1 m = in 1 gal = 4 qt 1 qt = 4 cups 1 mile = 5280 feet g = 1 lb 1 yd = 36 in = 3 ft 1 lb = 16 oz 1 atm = kpa = bar = 14.7 psi ºF = 1.8 º C + 32 N a = 6.02 x calorie = J For gases: standard T = K, P = 1 atm q = Energy = (mass) (C sp ) (ΔT) specific heat of water = J/g C average atomic mass = (mass isotope 1)(%) + (mass isotope 2)(%) + (mass isotope 3)(%) 100% P O2 = (% O 2 ) P T P 1 V 1 / T 1 = P 2 V 2 / T 2 P T = P 1 + P 2 + P 3 + PV=nRT w = -P ΔV λ = c ν $ E = J Z n 1 ' & 2 ) % 2 n 1 ( E = hν λ = h mv KE = ½ mv2 ΔxmΔv = h 4π Mass of electron = kg h = J s K w = [H 3 O + ] [OH ] = [H + ] [OH ] = c = m/s C 1 V 1 = C 2 V 2 % yield = actual/theoretical 100% 1 L atm = J R= L atm/mol K = J/mol K Specific heat of ice: 2.09 J/g C Specific heat of water: J/g C Specific heat of steam: 2.03 J/g C Heat of fusion of H 2 O = ΔH fus = 6.02 kj/mol Heat of vaporization of H 2 O = ΔH vap = 40.7 kj/mol " ΔT = m i K π = i M R T ln P % 2 $ ' = ΔH " vap 1 1 % $ # P 1 & R # T 2 T 1 & ' 1 ppm = 1 x 10-6 g/ml 1 ppb = 1 x 10-9 g/ml 1

Chemistry 400 Conversions and Equations Average Single Bond Dissociation Energy (in kj/mol) H C N O F Si P S Cl Br I 436 414 389 464 565 323 322 368 431 364 297 H 347 305 360 485 301 272 339 276 213

8 Chemistry 400 Conversions and Equations Average Single Bond Dissociation Energy (in kj/mol) H C N O F Si P S Cl Br I H C N O F Si P S Cl Br 151 I Comparison of Average Single, Double and Triple Bond Energies (in kj/mol) Bond Type Single Bond Double Bond Triple Bond C C N N O O C N C O * 1072 C Cl *For CO 2, the C=O bond is 799 kj/mol Boiling Point Elevation and Freezing Point Depression Constants Solvent Formula K b ( C/m) K f ( C/m) Water H 2 O Ethanol CH 3 CH 2 OH Chloroform CHCl Benzene C 6 H Diethyl ether CH 3 CH 2 OCH 2 CH Element Electronegativity F 4.0 O 3.5 Cl 3.0 N 3.0 S 2.8 Br 2.8 C 2.5 H 2.1 2

9 Chemistry 400 Conversions and Equations Material ΔH f (kj/mol) Material ΔH f (kj/mol) Ag(s) 0 H + (aq) 0 Ag + (aq) H 2 (g) 0 Al(s) 0 H 2 O(g) Al 3+ (aq) H 2 O(l) Al 2 O 3 (s) H 2 O(s) AlCl 3 (aq) H 2 O 2 (aq) AlCl 3 (s) H 2 O 2 (l) Br(g) H 3 O + (aq) Br 2 (g) 30.9 HBr(g) 36.3 Br 2 (l) 0 HCl(aq) C(g) HCl(g) 92.3 C(s, dia) 1.88 H 2 SO 4 (l) 814 C(s, gr) 0 HgO(s) 90.8 C 2 H 4 (g) 52.4 Hg(l) 0 C 2 H 4 O(g) I 2 (g) C 2 H 5 OH(l) I 2 (s) 0 acetate ion(aq) Mg 2+ (aq) acetic acid(aq) MgCl 2 (aq) acetic acid(l) N(g) C 6 H 12 O 6 (s) N 2 (g) 0 C 3 H 8 (g) N 2 H 4 (l) 50.6 butane(g) N 2 O(g) 81.6 butane(l) N 2 O 4 (g) 11.1 hexane(l) Na(s) 0 octane(l) Na + (aq) Ca(g) Na 2 SO 4 (s) Ca(OH) 2 (aq) 1003 NaCl(aq) Ca(OH) 2 (s) NaCl(s) Ca(s) 0 NaOH(aq) Ca 2+ (aq) NH 3 (aq) Ca 2+ (g) NH 3 (g) 45.9 CaCl 2 (s) NH + 4 (aq) CaCO 3 (s) NH 4 Cl(aq) CaF 2 (s) NH 4 Cl(s) CaO(s) NH 4 NO 3 (aq) CH 3 OH(g) NH 4 NO 3 (s) CH 4 (g) 74.6 NI 3 (s) 192 CHCl 3 (l) 134 NO(g) 91.3 Cl (aq) NO 2 (g) 33.2 Cl(g) O(g) Cl 2 (g) 0 O 2 (g) 0 ClF 3 (g) O 3 (g) CO(g) OH (aq) CO 2 (g) SO 2 Cl 2 (g) 364 Cu(s) 0 SO 2 (g) Cu 2+ (aq) 64.9 SO 2 4 (aq) CuCl 2 (s) S 2- (aq) 33.1 CuSO 4 (s) Zn(s) 0 F(g) Zn 2+ (aq) F (aq) HgO(s) 90.8 Fe 2 O 3 (s) 824 Hg(l) 0 Fe 3 O 4 (s) 1118 H(g) 218 3

Chemistry 400: General Chemistry Miller Fall 2015 Final Exam Part Deux December 14, 2015 Approximately 150 points

Chemistry 400: General Chemistry Name: Miller Fall 2015 Final Exam Part Deux December 14, 2015 Approximately 150 points Please answer each of the following questions to the best of your ability. If you