Soal Latihan Kimia Dasar II (28-05-2013)Waktu 2 jam

1. At 25 C, the vapor pressure of pure benzene is 100 torr, while that of pure ethyl alcohol is 44 torr. Assuming ideal behavior, calculate the vapor pressure at 25 C of a solution which contains 10.0 g of each substance. 2. The freezing point of a sample of naphthalene was found to be 80.6 C. When 0.512 g of a substance is dissolved in 7.03 g naphthalene, the solution has a freezing point of 75.2 C. What is the molecular weight of the solute? The molal freezing constant of naphthalene is 6.80 C.kg/mol3. How long will it take for a uniform current of 6.0 A to deposit 78.0 g gold from a solution of AuCl4-? When mass of chlorine gas will be formed simultaneously at the anode of the electrolytic cell?4. For the following cell reactions, write each half-cell reaction, and calculate E and E for the cell.Hg2Cl2(s) 2 Hg(l) +Cl2 (0.80 atm)EHg2Cl2 = 0.270 V ECl2 = 1.36 V5. A pure radiochemical preparation was observed to disintegrate at the rate 4280 counts/min at 1:35 p.m. At 4:55 p.m. of the same day, the disintegration rate of the sample was only 1070 counts/min. The disintegration rate is proportional to the number of radioactive atoms in the sample. What is the half-life of the material?6. The suns energy is believed to come from a series of nuclear reactions, the overall result of which is the transformation of four hydrogen atoms into one helium atom. How much energy is released in the formation of one helium atom?a. 1H: 1.00783 u and 4He: 4.00260 u7. Name the following (where en=ethylenediamine, py=pyridine):a. [Cr(en)2Cl2]Clb. [Pt(py)4][PtCl4]8. Write formulas for the following compounds:a. Sulfatopentaamminecobalt(III) bromideb. Ammonium heptafluorozirconate(IV)