Part A.Answer all eight questions(5 marks each). 1.What kind of hybrid orbitals does the S atom use in a molecule of H2S? H、 S The structure of H2S is Since this structure has two lone pairs and two bonding pairs about theS atom,then the S atom must be using sp'hybrid orbitals. 2.In a buffered system composed of (C2Hs)N and(C2Hs)NHCl)will the pH increase or decrease as more (C2Hs)3NHCl(ag)is added?Why? din o the Hendern bIe id sh (C2Hs)3NHCla Adding more of it will therefore lower the pH. 3.Name the strongest intermolecular force between two molecules of(CH3)NH.Be specific. Due to the polar N-H bonds,two molecules of this compound will be attracted by H-bonds. 4.For the reaction MgCO=MgOs+COx),which way will the equilibrium shift if pressure is increased? Why? The equilibrium will shift left so as to reduce the pressure.Note that there is only one gaseous species in the e reaction 5.Define the term"state function"and give three examples of one. e function is one whose value is the same no matter wh path istaken om reactants to products.Some examples are S.H..V. eaction and no matter what Part B.Answer all four questions(20 marks each). 1. For the reaction H+CO=CO+H2O at equilibrium at 25C,the following partial pressures were measured: Pa =0.387atm Pco =0.152atm Peo=.180atm Pu.o=0.252atm (a)Calculate the equilibrium constant Kp K=PcoPu,o PHa Pcoz _01800252=0.71 (0.387)0.152)Part A. Answer all eight questions (5 marks each). 1. What kind of hybrid orbitals does the S atom use in a molecule of H2S? The structure of H2S is Since this structure has two lone pairs and two bonding pairs about the S atom, then the S atom must be using sp3 hybrid orbitals. S H H .. .. 2. In a buffered system composed of (C2H5)3N(aq) and (C2H5)3NHCl(aq), will the pH increase or decrease as more (C2H5)3NHCl(aq) is added? Why? According to the Henderson Hasslebalch equation, a 10 [acid] pH pK log [base] = + . In this system, the acid is the (C2H5)3NHCl(aq). Adding more of it will therefore lower the pH. 3. Name the strongest intermolecular force between two molecules of (CH3)2NH. Be specific. Due to the polar N-H bonds, two molecules of this compound will be attracted by H-bonds. 4. For the reaction MgCO3(s) = MgO(s) + CO2(g), which way will the equilibrium shift if pressure is increased? Why? The equilibrium will shift left so as to reduce the pressure. Note that there is only one gaseous species in the reaction. 5. Define the term “state function” and give three examples of one. A state function is one whose value is the same no matter what the rate of reaction and no matter what path is taken from reactants to products. Some examples are S, H, G, p, V, T. Part B. Answer all four questions (20 marks each). 1. For the reaction H2(g) + CO2(g) = CO(g) + H2O(g) at equilibrium at 25o C, the following partial pressures were measured: 2(g) 2(g) (g) 2 (g) H CO CO H O p 0.387 atm p 0.152atm p 0.180atm p 0.252atm = = = = (a) Calculate the equilibrium constant Kp 2 2 2 CO H O p H CO p p K p p (0.180)(0.252) 0.771 (0.387)(0.152) = = =