课程名称︰普通化学乙上 课程性质︰必修 课程教师︰彭旭明 开课学院：理学院 开课系所︰心理系 森林系 考试日期（年月日）︰2011/11/16 考试时限（分钟）：120 min 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. Write the formulas for these compounds: (6%) (a) disodium ammonium phosphate (b) perchloric acid (c) hydroiodic acid (d) rubidium nitrite (e) iodine heptafluoride (f) iron(III) chromate 2. Name these compounds in English: (6%) (a) K2Cr2O7 (b) K2HPO4 (c) NH4NO2 (d) Na2CO3．10H2O (e) FeCl2 (f) KMnO4 3. (8%) (a) Describe Rutherford's experiment and how it led to the structure of the atom. How was he able to estimate the number of protons in a nucleas from the scattering of the α particles? (b) Consider the Na(23) atom. Given that the radius and mass of the nucleus are 3.04 ×10^-15 m and 3.82 ×10^-23 g, respectively, calculate the density of the space occupied by the electrons in the sodium atom. Do your results support Rutherford's model of an atom? [The volume of a sphere is (4/3)πr^3, where r is radius.] 4. A sample of iron weighting 15.0 g was heated wit potassium chlorate (KClO3) in an evacuated container. The Oxygen generated from the decomposition of KClO3 converted some of the Fe to Fe2O3. if the combined mass of Fe and Fe2O3 was 17.9 g, calculate the mass of Fe2O3 formed and the mass of KClO3 decomposed.(6%) 5. Ammonium nitrate (NH4NO3) is one of the most important nitrogen-containing fertilizers. Its purity can be analyzed by titrating a solution of NH4NO3 with a standard NaOH solution. in one experiment a 0.2041 g sample of industrially prepared NH4NO3 required 24.42 mL of 0.1023 M NaOH for neutralization. (6%) (a) Write a ionic equation for the reaction. (b) What is the percent purity of the sample? 6. The concentration of Cu(2+) ions in the water (which also contains sulfate ions) discharged from a certain industrial plant is determined by adding exess sodium sulfate (Na2S) solutoin to 0.8000 L of the water. The molecular equation is: Na2S(aq) + CuSO4(aq) → Na2SO4(aq) + CuS(s) Write the net ionic equation and calculate the molar concentraton of Cu(2+) in the water sample if 0.0177 g of solid CuS is formed. (6%) 7. A 5.012g sample of an iron chloride hydrate was dried in an oven. The mass of the anhydrous compound was 3.159 g. The compound was dissolved in water snd reacted with an excess of AgNO3. The precipitate of AgCl formed weighted 7.225 g. What is the formula of the original compund? (6%) 8. The maximum of each speed distribution plot is called the most probable speed (μmp) because it is the speed posessed by the largest number of molucules. It is given by: (6%) μmp = √(2RT/M) (a) Compare μmp with μrms for nitrogen at 25。C. (μrms is root-mean-square speed) (b) The following diagram shows the Maxwell speed distribution curves for an ideal gas at two different T1 and T2. Calculate the value of T2. (T1=300K，图形的顶峰对应的molecular speed是 500 m/s T2图形的顶峰对应的molecular speed是 1000 m/s) 9. A barometer having a cross-sectional area of 1.00 cm^2 at a sea level measures a pressure of 76.0 cm of mercury. The pressure exerted by this column of mercury is equal to the pressure exerted by all the air on 1 cm^2 of Earth's surface. Given that the density of mercury is 13.6g/mL, and the average rarius of Earth is 6371 km. Calculate the total mass of Earth's atmosphere in kiloframs. (6%) (Hint: The surface area of a sphere is 4πr^2) 10. The density of a pure gaseous compound was measures at 0.00。C as a function of pressure to give the following results: ───────────────────── Density (g/L) Pressure(atm) ───────────────────── 0.17893 0.2500 0.35808 0.5000 0.53745 0.7500 0.71707 1.000 ───────────────────── Calculate the molar mass of this compound, crrected for any nonideal behavior of the gas. (R = 0.08206 L atm mol^-1 K^-1)(8%) 11. (6%) (a) A person drinks 4 glassed of cold water (3.0。C) every day. The volume of each glass is 250 mL. How much heat (in kJ) does the body have to supply to raise the temperature of the water to 37。C, the body temperature? (b) How much heat would your body lose if you were to injest 800 g of snow at 0。C to quench thirst? (The amount of heat necessary to melt snow is 6.01 kJ/mol) 12. For hydrogenlike ions, that is, ions containing only one electron, equaton (7.5) is modified as follows: En = -R Z^2(1/n^2), where Z is the atomic number of the parent atom. The figure here represents the emission spectrum of such a hydrogenlike ion is the gas phase. All the lines result from the electronic transitions from exited states to then n=2 state.(8%) (a) What electronic transitions correspond to the lines B and C. (b) If the wavelength of line C is 27.1 nm, calculate the wavelengths of lines A and B. (c) Calculate the energy needed to remove the electron from the ion in the n=1 state. (d) What is the physical significance of the continuum? C B A █▍▎▏▏│ │ │ █▍▎▏▏│ │ │ █▍▎▏▏│ │ │ █▍▎▏▏│ │ │ ───────────→ λ 13. Indicate the electron configuraton and the number of upaired electrons present in each of the following atoms: B, Mn, Se, Fe, I. (10%) 14. Consider the followinf energy levels of a hypothetical atom; (6%) E4____________ -1.0 ×10^-19 J E3____________ -5.0 ×10^-19 J E2____________ -10 ×10^-19 J E1____________ -15 ×10^-19 J (a) What is the wavelength of the photon needed tp exite an electron from E1 to E4? (b) What is the energy (in J) a photon must have in order to exite an electron from E2 to E3? (c) When an electron drops from E3 level to E1 level, the atom is said to undergo emission. Calculate the wavelength of the photon emitted in this process. 15. Suppose that you begin at a distance far from the nucleus on the z axis, through the nucleus to a distance far on the -z axis. How many nodal surfaces would you pass through for each of following orbitals: (5%) (a) 1s (b) 2s (c) 2pz (d) 3pz (e) 3dz^2 16. For a hydrogen atom in its ground state, the wavefunction is: 1 ╭ 1 ╮^3/2 Ψls = ──│──│ e^(-r/a0), a0 = 5.29 ×10^-11 m √π╰ a0 ╯ Calculate the relative probability of finding the electron in the area described. Assuming the probability of a sphere of volume is identical. (a) in a sphere of volume 1.0 ×10^-3 pm^3 centered at nucleus. (b) in a sphere of volume 1.0 ×10^-3 pm^3 centered on a point 1.0 ×10^-11 m from the nucleus. (c) in a sphere of volume 1.0 ×10^-3 pm^3 centered on a point 53 pm from the nucleus. (d) in a shell between two concentric spheres, one with rarius 9.95 pm and the other with radius 10.05 pm. (e) in a shell between two concentric spheres, one with rarius 52.85 pm and the other with radius 52.95 pm. --

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