130 Chem Exam 2 Fall 2005 1. Which of the following orbital representations is (are) allowed? 1. 3s 2. 3p 3. 3d a. b. c. d. e. 1 only 2 only 3 only 1 and 2 only 1, 2, and 3
2. At standard conditions (STP), 2.75 L of a gas weighed 5.39 g. The gas is a. NO b. N2 c. F2 d. N2O e. NF3 3. The temperature of a gas in a sealed container changes from 313 K to 353 K. If the volume remains constant, the pressure will change from 750 mmHg to a. 375 mmHg b. 665 mmHg c. 846 mmHg d. 893 mmHg e. 1500 mmHg 4. Which of the following samples has the least moles of gas? a. 1.00 L of HCl at 20oC and 1.00 atm b. 1.00 L of CH4 at STP c. 1.00 L of H2 at 0.0oC and 1.10 atm d. 1.00 L of NH3 at STP e. 1.00 L of Ar at -10.0oC and 1.00 atm 5. The following two reactions are known: Fe2O3(s) + 3CO(g) = 2Fe(s) + 3CO2(g) delta H = -26.8 kJ FeO(s) + CO(g) = Fe(s) + CO2(g) delta H = -16.5 kJ Determine the delta H value for the reaction below Fe2O3(s) + CO(g) = 2FeO(s) + CO2(g) a. -43.3 kJ b. -10.3 kJ c. 6.2 kJ d. 10.3 kJ e. 22.7 kJ
6. What is the partial pressure of oxygen in a container that contains 2.0 mol of oxygen, 3.0 mol of nitrogen, and 1.0 mol of carbon dioxide when the total pressure is 900 mmHg? a. 150 mmHg b. 200 mmHg c. 300 mmHg d. 450 mmHg e. 600 mmHg 7. Which radiation has the longest wavelength? a. blue light b. gamma rays c. red light d. x-rays e. microwaves 8. The maximum number of electrons in a 4d subshell is a. 1 b. 3 c. 5 d. 8 e. 10 9. The value of the angular momentum quantum number for a 4f electron is a. 0 b. 1 c. 2 d. 3 e. 4 10. The formation reaction for NH3(g) is a. N2(g) + 3H(g) = NH3(g) b. N(g) + 3H(g) = NH3(g) c. N2(g) + 3/2H2(g) = NH3(g) d. N(g) + 3/2H2(g) = NH3(g) e. N2(g) + H2(g) = NH3(g) 11. The sign of delta H for the process NaCl(s) = NaCl(l) is a. positive, and the process is exothermic b. negative, and the process is endothermic c. positive, and the process is endothermic d. negative, and the process is exothermic e. impossible to predict because delta Hof for NaCl(s) and delta Hof for NaCl(l) are not given
12. What is the quantity of heat evolved when 200 g H2O(l) is formed from the combustion of H2(g) and O2(g)? H2(g) + O2(g) = H2O(l) delta H = -285.8kJ a. 285.8 kJ b. 1590 kJ c. 3170 kJ d. 4360 kJ e. 57200 kJ 13. H2 and F2 react according to the following equation, forming HF. H2 + F2 = 2HF delta H = -271kJ/mol If H2(g) and F2(g) were mixed in a thermally insulated vessel, the reaction that occurred would be a. b. c. d. e. endothermic, and the temperature of the reaction system would rise exothermic, and the temperature of the reaction system would rise endothermic, and the temperature of the reaction system would fall exothermic, and the temperature of the reaction system would fall we could not tell unless the original and final temperatures were given
14. To dilute a solution from 0.600 M to 0.100 M the final volume must be: a. 6 times the original volume b. 1/6 the original volume c. 60 L d. 0.7 L e. more information is needed to answer this question 15. What volume of 0.200 Na2CO3 M (FW = 106) solution contains 53.0 g of Na2CO3? a. 0.500 L b. 0.200 L c. 1.60 L d. 0.400 L e. 2.50 L 16. How many values are there for the magnetic quantum number when the value of the angular momentum quantum number is 3? a. 1 b. 3 c. 5 d. 7 e. 9
17. 350.0 mL of 2.50 M HCl are added to 400.0 mL of 5.00 M HCl. Assuming that the volumes are additive, the final concentration is a. 4.17 M b. 3.65 M c. 4.33 M d. 3.83 M e. 4.50 M 18. Consider the following specific heats of metals. Metal Specific Heat Lithium 3.56 J/(goC) Gallium 0.372 J/(goC) Nickel 0.444 J/(goC) Gold 0.129 J/(goC) Sodium 1.23 J/(goC) If the same amount of heat is added to 200 g samples of each of the metals, which are all at the same temperature, which metal will attain the lowest temperature? a. b. c. d. e. nickel lithium gold gallium sodium
19. What is the wavelength of light in nanometers having a frequency of 1.5 x 1018 s-1? (The speed of light is 3.00 x 108 m/s) a. 2.0 x 10-3 b. 2.0 x 10-1 c. 5.0 x 1016 d. 5.0 x 1018 e. 4.5 x 1035 20. When ammonium nitrate undergoes decomposition, only gases are produced, according to the equation NH4NO3(s) = N2O(g) + 2H2O(g) What is the total volume of gases produced at 546 K and 1.00 atm pressure when 240 g of ammonium nitrate undergoes the above decomposition reaction? a. 201.6 L b. 67.2 L c. 268.8 L d. 134.4 L e. 403.2 L
21. A soluble salt, MX, is added to water in a beaker. The experiment is performed at room temperature. The thermochemical equation for the dissolving of the salt is: MX(s) = M+(aq) + X-(aq) delta H > 0 Circle your answer to each of the following statements: a. immediately after the salt dissolves, the solution is i. warmer ii. colder b. the heat flows i. into the beaker ii. out of the beaker
c. after the salt dissolves and the solution returns to room temperature, the value of the heat of reaction is i. positive ii. zero iii. Negative 22. True/False questions Circle your answer to each of the following statements: a. When a closed-end manometer is used for pressure measurements, and the closed end is under vacuum, the level of mercury in the closed arm can never be lower than that in the other arm. T F b. Line spectra are characteristic of atoms in the gas phase. T F c. In the Rydberg equation, for a series of spectral lines with fixed value of n1, the longest wavelength line has n2 = infinity. T F d. In the quantum mechanical treatment of the hydrogen atom, the probability of finding an electron at any point is proportional to the wave function. T F
23. a. Draw a graph representing the pressure-volume relationship for ideal gases (Boyle's law). Your graph should have correctly labeled axes and you should write what are the necessary conditions for the law to be obeyed.
b. Draw the graph representing the energy levels for a Hydrogen atom. Label all the lines you draw with appropriate letters, symbols, and/org numbers.
c. Sketch the shape of the dxz orbital. Make sure your drawing has all necessary details allowing identification of this orbital.