课程名称︰普通化学甲 课程性质︰必带 课程教师︰许益瑞 开课系所︰农业化学系 　大气科学系 　地质科学系 考试日期︰Nov.-14th-2008 考试时限：140分钟 是否需发放奖励金：是 试题 :〈不附图〉 1. (a) Four students (A, B, C and D) measure 25.0 mL of water on a balance. If the density of water is 1.00g/mL ate the temperature of the experiment, following graphs are the results from the four students. (i) Which student(s) yield the same average result? (2 points) (ii) Which student(s) display high precision? (2 points) (iii) Which student(s) diaplay high accuracy? (2 points) (iv) Which student(s) show(s) a systematic error? (2 points) (b) Carry out the following calculations, paying special attention to siginificant figures, rounding, and units (J=joule, the SI unit of energy; mol=mole, the SI unit of amount of substance) (2 points) (6.022 x 10^23 atms/mol)(2.18 x 10^-18 J/atom)(1/2^2 - 1/3^2), where the number 2 and 3 in the last term are exact number. 2. Hemoglobin, a protein in red blood cells, carries O2 from the lungs to the body's cells. The most important part in charge of the O2 transportation is the heme group with the formula C34H32FeN4O4. The numbers of heme groups are unknown in the protein. According to some analysis, the molar mass of hemoglobin is about 6.8 x 10^4 g/mol and the iron (as ferrous ion, Fe2+) makes up 0.33 mass % of this protein. To remove the heme, hemoglobin is treated with acetic acid and NaCl to form hemin (C34H32N4O4FeCl). Please answer the following questions: (a) How many Fe2+ ions are in one hemoglobin protein? (3 points) (b) What is the mass % of heme in hemoglobin (ie: heme/hemoglobin)? (2 points) (c) At a crime scene, a blood sample contains 0.45g of hemoglobin. How many grams of heme, Fe, and hemin could be formed for a forensic chemist to measure? (5 points) 3. Draw the structures or give the name of each compound (including geometric isomers): (2 points for each one) (i) trans-2, 3-dimethyl-3-hexene (ii) (iii) NaNO2 (iv) Fe(ClO4)2 (v) barium hydroxide octahydrate (vi) ethanol→(oxidation)ethanal (vii) 3-pentanol→(oxidation)3-pentanone 4. Complete and balance each of the following reactions. (3 points for each one) (a) Ms(s)+Fe(NO3)3(aq)→Mn(NO3)2(aq)+Fe(s) (b) Calcium hydroxide+nitric acid (c) HCl(aq)+NH4Cl(aq)+K2Cr2O7(aq)→KCl(aq)+CrCl3(aq)+N2(g)+H2O(l) (d) IO3-(aq)+H+(aq)+I-(aq)→I2(aq)+H2O(l) 5. Calcium dihydrogen phosphate, Ca(H2PO4)2, and sodium hydrogen carbonate, NaHCO3, are ingredients of baking powder that react with each other to produce CO2, which causes dough or batter to rise: (10 points) Ca(H2PO4)2(s)+NaHCO3(s)→CO2(g)+H2O(g)+CaHPO4(s)+Na2HPO4(s) [unbalanced] If the baking powder contains 31% NaHCO3 and 35% Ca(H2PO4)2 by mass: (a) How many moles of CO2 are produced from 1.00g of baking powder? (b) If 1 mol of CO2 occupies 37.0 L at 350.0^oF (a baking temparature), what volume of CO2 is produced from 1.00g of baking powder? 6. Three 5-L flasks, fixed with pressure gauges and small valves, each contain 4 g of gas at 273K. Flask A contains H2, flask B contains He, and flask C contains CH4. Rank the flask contents in terms of (a) pressure, (b) average molecular kinetic energy, (c) diffusion rate after the valve is opened, (d) total kinetic energy of the moleciles, (e) density (3 points for each one) 7. A balloonist is preparing to make a trip in a helium-filled balloon. The trip begins in the early morning at a temperature of 15.0^oC. By mid afternoon, the temperature has increased to 30.0^oC. Assuming the pressure remains constant at 1.00 atm, for each of helium, calculate: (a) The initial and final volumes (2 points) (b) The change in initial energy, ΔE. (Hint: Helium bahaves like a ideal gas) (2 points) (c) The work (w) done by the helium (in J) (2 points) (d) The heat (q) transferred (in J) (2 points) (e) ΔH for the process (in J) (2 points) (f) Explain the relationship between the answers (d) and (e) (2 points) 8. Fatty acids and sugars are the building blocks of fats and carbonhydrates, respectively, two of the major sources of energy in the diet. Please answer the following questions: (12 points) (a) Compare the energy released upon combustion per gram of long-chain fatty acids such as palmitic acid, CH3(CH2)14CO2H (ΔH^of=-891.5 KJ/mol) and glucose C6H12O6 (ΔH^of=-1273.3 KJ/mol) (b) Calculate the amount of available energy obtained from the biological oxidation of 1.000g of the amino acid alanine(C3H7NO2). Remember that the nitrogen-containing product is urea, not N2, so biological oxidation of alanine will yield less energy than that of combustion. The value of ΔHcomb for alanine is -1577 KJ/mol. (c) What is the minimum number of Calories expended by a 160-lb person who climbs a 30-story building? (Assume each flight of stairs is 14 ft high.) If the body is only about 30% efficient in using the energy in glucose, how many grams of glucose are required to supply this amount of energy? (1 lb=454g, 1 ft=12in, 1 in.=2.54cm) 9. (a) According to the following data at 450^oC, please find the rate law and the overall reaction order for the reaction, (3 points) H2(g)+I2(g)→2HI(g) Experiment Initial Rate(mol/L‧s) Initial[H2](mol/L‧s) Initial[I2](mol/L‧s) 1 1.9 x 10^-23 0.0113 0.0011 2 1.1 x 10^-22 0.0220 0.0033 3 9.3 x 10^-23 0.0550 0.0011 4 1.9 x 10^-22 0.0220 0.0056 (b) At 25^oC, hydrogen iodide breaks down very slowly to hydrogen and iodine. 2HI(g)→H2(g)+I2(g) Give the rate constants of 9.51 x 10^-9 L/mol‧s at 500.0K and 1.10 x 10^-5 L/mol‧s at 600.0K. (i) Please find the Ea value? (ii) Can you estimate the rate constant at 25^oC? (Assume Ea is temperature independent. (8 points) (c) If Iodine-123 is used to study thyroid gland function. This radioactive isotope breaks down in a first-order process with a half-life of 13.1 hours. What is the rate constant for the process? (4 points) (d) Based on some spectroscopic evidence, the reaction mechanism of (a) is proposed by a three-step reactions: (5 points) (1) I2(g)←→2I(g) [fast] (2) H2(g)+I(g)←→H2I(g) [fast] (3) H2I(g)+I(g)→2HI(g) [slow] Show that this mechanism is consistent with the rate law of (a). 10. The mean free path can be calculated by the formula, λ=kT/{[2^(1/2)]π(d^2)P}, where d is collision diameter. For oxygen at 25^oC, the collision diameter is 0.361 nm. What is the mean free path with an external pressure at (1) 10 bar and 1 Pa? (2) Which one is suitable for the idea gas law? If the 1 mol O2 gas is stored in 1 liter container. Please adjust the real gas pressure for the one which is not suitable for the idea gas law. (The van der Waals constants a and b of oxygen gas are 1.36 atm‧L^2/mol^2 and 0.0318 L/mol, respectively.) (8 points) Some useful information: 不赘述了。 --

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