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（年月日）︰Jan.-16th-2009 考试时限（分钟）：140分钟 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1.Fish-liver oil is a good source of vitamin A, which is measured spectrophotometrically at a wavelength of 329nm. (a)In what region of the spectrum does this wavelength lie?(2 points) (b)When 0.1232g of fish-liver oil is dissolved in 500.0 ml of solvent, the absorbance is 0.724 units.When 1.67*10^-3g of vitamin A is dissolved in 250.0 ml of solvent, the absorbance is 1.018 units. Calculate the vitamins A concerntration in the fish-liver oil.(8 points) 2.After we solved the Schrodinger equation of hydrogen atom, the quantized energy and atomic orbital of 1s, 2s, and the 3s are given as following, En=-h^2/(8π^2 Me a0^2 n^2) (n=1,2,3......),h is Planck's costant, Me is the electron mass and a0 is 0.5292 A Ψ100(r)= 1/√π* (1/a0)^3/2 * e^-σ Ψ200(r)= 1/4√2π* (1/a0)^3/2 * (2-σ)e^-σ Ψ300(r)= 81/√3π* (1/a0)^3/2 * (2-18σ-2σ^2)e^-σ/3 σ=r/a0, a0 = 0.5292 please answer the question. (a)What physical meaning is attributed to the square of the wave function, |Ψ|^2 (3 points) (b)Explain your own words it means for the peak in the radial probability distribution 4πr^2*|Ψ100|^2 plot for the hydrogen 1s orbital at a0=0.529A(3 points) (c)If the electron moving near the atomic nuclear has a speed of 6*10^6m/s ±1%.What is the uncertainty in its position?(4 points) (d)According to the result of(c), do you think we can precisely locate the electron? Explain your answer.(4 points) (e)How many nodes you can find in Ψ100,Ψ200 andΨ300?(3 points) (f)Find the ΔE between n=2 and n=3, and its corresponding wavelength? (4point) 3.(a)Draw the H2 Molecular Orbital (MO) diagrams( 5points) (b)Use the MO diagram in (a) to predict whether H2+ and H2- exist? Determine their bond order and electron configuration (6 points) 4.Nitrogen monoxide (NO) is an odd electron molecule with a vital biochemical function. Heating NO can convert it to N2O and NO2. (a)Please write down and balance the chemical reaction.(3 points) (b)Please write down the most stable Lewis structure of N2O, and its oxidation state of each N, and explain the molecular shape N2O by VSEPR theory(6 points) (c)NO2 has many resonance forms. Please drow two Lewis resonance structure with one lone electron and one double bond, and assign the formal charge to each atomin these two structure.(3 points) (d)If two NO2 collide to form N2O4, please draw the Lewis structure of N2O4 and explain which form in (c) is more important in this reaction. (4 points) (e)Please draw the Lewis structure of nitronium ion (NO2+) and nitrite ion (NO2-).(4 points) (f)Please use VSEPR theory to explain the bond angle differences among NO2+, NO2, NO2- .(6 points) 5.Draw the molecular shapes and predict the bond angles (relative the ideal angle ) of (i)COCl2(ii)SF2(iii)S2F2(iv)SOF4(v)BrF5 (2 poimts for each) 6.Please draw the following orbital shapes.(The horison and vertical axes should be labeled. )(10 points) (a)Px(b)Pz(c)dxy(d)dx2-y2(e)dxz 7.(a)Rank the ion in each set in order of increasing size and explain your reason.(i)Li+,K+,Na+(ii)O2-,F-,N3-(3 points for each one) (b)Arrange the following set in order of increasing bond strength: (i)H-Br,H-Cl,H-I(ii)C-C,C=C,C≡C (3 points for each one) (c)Rank the members of each set of compounds in order of increasing ionic character of their bonds. Use polar arrows to indicate the bond polarity of each: (i)HBr,HCl,HI (ii)H2O,CH4,HF (iii)SCl2,PCl3,SiCl4 (3 points for each one) 8.The treatment of partical in a one-dimentional box can be extended to a rectangular box of dimensions Lx,Ly,Lz, yielding the following expression of energy: E=h^2/8m * (nx2/Lx2+ny2/Ly2+nz2/Lz2) The three quantum number nx,ny,nz independently can assume only interger values. (a)Determine the energies of the three lowerest levels, assuming that the box is cubic.(3 points) (b)Describe the degeneracies of all the levels that correspond to quantum numbers having value of 1 or 2. How will these degeneracies change in a box where LX≠ LY≠ LZ(3 points) 9.(a)Write the condensed ground-state electron configuration of these transitions metal ions, and the state which are paramagnetic or diamagnetic ions: (i)Co2+ (ii)Mn2+ (iii)Mo3+(3 points) (b)Some chemist found that the ClO2-,ClO-,Cl- can form CuClO2, CuClO and CuCl2. (i)What is the oxidation number of Cu in each compounds? Which copper ion is a paramagnetic ion?(3 points) (ii)What is the oxidation number of Cu in each compound?(3 points) (iii)In order to estimate the effective nuclear charge Zeff=Z-σ,where Z is the atomic number and σ is the screen constants, Slater gave empirical method to estimate the screen constant,σ. For an electron in an orbital with principal quantum number n, the screen effect is mainly from the other electron with quantum number less or equal to n. According to his rule, we can make a summery table as follow,(10 points) ┌──────┬──────┬──────┬──────┬──────┐ │ │n'=n-1 │n'=n-1 │n'=n │ n'>n │ ├──────┼──────┼──────┼──────┼──────┤ │1s │ │ │0.30 │0 │ ├──────┼──────┼──────┼──────┼──────┤ │ns,np │1 │0.85 │0.35 │0 │ ├──────┼──────┼──────┼──────┼──────┤ │nd,nf 　　│1 │1 │0.35 │0 │ └──────┴──────┴──────┴──────┴──────┘ For example, Z=15, 1s2 2s2 2p6 3s2 3p3 An electron in n =2, theσ2s2p=2*0.85+7*0.35=4.15, so that Zeff= 15- 4.15= 9.85 According to this rule, please calculate the Zeff of an electron with n=3 of all Cl in three compounds. --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 140.112.251.181