※ [本文转录自 NTU-Exam 看板] 作者: youngsam (要加油要加油) 看板: NTU-Exam 标题: [试题] 93上化学系普通化学甲期末考 牟中原陈振中合开 时间: Wed Feb 16 22:06:42 2005 课程名称︰普通化学甲上 班次︰01(化学系) 课程性质︰必修 课程教师︰牟中原 陈振中合开 开课系所︰化学系 考试时间︰2005.01.12 试题 : 国立台湾大学 九十三学年度 第一学期 化学系 普通化学甲 期末考 2005年 1月 12日 Planck's constant 6.6X10^-34 J s Electron mass 9.1X10^-31 kg Light speed 3.0X10^8 m/s MHz = 10^6 Hz μs = 10^-6 sec femtosecond = 10^-15 sec 1. (10%) Consider an EM wave of freduency equal to 300MHz, how many quanta will be emitted if we switch on the source (1kW) for 5μs? 2. (10%) Write down the orbital diagram of a silicon atom. Sketch the shapes of py, dz2, dxz and dx2-y2 orbitals(indicate the signs of the lobes). 3. (20%) Given the first ionization energies shown in the following diagram: (a) Explain the general trend of the data across a period. (b) Explain why the first ionization energy drops from Be to B, and from N to O. 4. (14%) The Balmer series has an equation of the following form: 1 1 1 ─── = R[─── ─ ───] λ 2^2 n^2 The energy expression of th Bohr's model of a one-electron atom: En = -2.178 X 10^-18( Z^2 / n^2 ) (a) Derive the value of R. (b) What is the shortest wavelength of the emission spectrum of Be^3+ 5. (10%) For a particlr in a two-dimensional box, all the orbitals and the corresponding energies can be written as x y φNx,Ny(x,y) = { √(2/a) sin(Nxπ─)}{√(2/b) sin(Nyπ─)} a b h^2 Nx^2 Ny^2 Energy = ( ── )(── + ──) 8m a^2 b^2 Nx= 1,2,3,4,..... Ny= 1,2,3,4,..... b=2a Suppose we have the same set of orbitals when eight particles are placed in the box. Each particles has a spin quantum number of 3/2. (a) If the particles do not obey the Pauli exclusion principle, mark the position(s) in the rectangular box where we can most likely find a particle at 0K. (b) If the particles obey the Pauli exclusion principle, mark the position(s) in the rectangular box where we can most likely find a particle at 0K. 6. (6%) In a rencent article [J. Itatani et al., Nature, 2004, vol. 432, pp 867-871], a group of scientists use femtosecond laser technology to inage the electron cloud of an N2 molecule. They first use a laser pulse (wavelength 800 nm) to ionize the N2 molecule: N2(g) → N2+(g) + e- The valence electron taken away from the N2+ molecule is then forced to collide with the parent N2+ molecule. Through this process, the recolliding electron has gained a lot of kinetic energy. Estimate the velocity of the recolliding electron. (Ignore the descriptions of "high harmonics","grating", and "orbital shadow".) 7. (14%) Cadmium sulfide (CdS) is used in some semiconductor applications. Calculate the value of the solubility product (Ksp) for CdS given the following standard reduction potentials: CdS + 2e- → Cd + S2- ε°= -1.21V Cd2+ + 2e- → Cd ε°= -0.402V 8. (16%) A zinc-copper battery is constructed as follows: Zn│Zn2+(0.10M)││Cu2+(2.50M)│Cu Zn2+ + 2e- → Zn ε°= -0.76V Cu2+ + ce- → Cu ε°= 0.34V The mass of each electrode is 200g. a. Calculate the cell potential when this battery is first connected. b. Calculate the cell potential after 10.0A of current has flowed for 10.0h (Assume each half-cell contains 1.00L of solution) c. Calculate the mass of each electrode after 10.0h d. How long can this battery deliver a current of 10.0A before it goes dead? -- ╭═╮╭╮═══╮═╮╭╮═══╮═══╮═══╮═══╮═╮═╮ ║▌╰╯║▌╭╮║▌║║║▌╭╮║╭╮▌║▌ ╯▌╭╮║▌╧ ║ ╰˙ ╭╯˙╰╯║˙╰╯║˙║║║╰╯˙║˙══╮˙╰╯║˙★╭║ ╰═╯ ═══╯═══╯═╯╰╯═╮ ║═══╯═╯╰╯ ╯ ╰╯ …∵‥∴…∵‥∴…∵‥∴…∵‥∴…╰══╯∵‥∴…∵‥∴…∵‥∴… --

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