9501 - 32 1>$I b R$ F ~ l l Sodium oxide(Na20 crystallizes...

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32 1 >$I) b- / % R$ ( Fl **& [~%%+l . Sodium oxide (Na20) crystallizes in a structure in which the 02- ions are in a face-centered cubic lattice and the ~a+ ions are in tetrahedral holes. The number of ions in the unit cell is: (a) 2 ('J) 3 (c) 4 (4 6 (e) 8 , A material is made fiom Al, Ga, and As. The mole fraction of each element is 0.25,0.26, and 0.49, respectively. This material would be (a) an n-type semiconductor (b) ap-type semiconductor (c) an insulator (d) a metallic conductor because A1 is present (e) none of the above . Which statement about semiconductor nanoparticles such as CdSe is incorrect? (a) Band gap of the material may decrease due to quantum confinement (b) Absorption band may blue-shift (c) Emission band may blue-shift (d) Relative intensities of the peaks in the XRD pattern may be different (e) Widths of the peaks in the XRD pattern may become broader. . In which of the following processes will energy be evolved as heat? (a) sublimation (b) melting (c) vaporization (d) crystallization (e) none of the above . Which of the following coordination compounds will form a precipitate when treated with aqueous solution of AgN03? (a) [CrCNH3)3Cbl (dl Na3 [CrClaI i. Classify the following molecule: (CH3)2CHNH2 (a) primary arnine (b) secondary arnine (d) amino acid (e) secondary alcohol (c) tertiary amine 1. Lead (11) nitrate reacts with sodium chloride in aqueous solution to form a precipitate. What is the net ionic equation for this reaction? (a) ~b~+(aq) + 2N03-(aq) -+ Pb(N03)2(s) (b) pb2+(aq) + 2C1-(aq) PbClz(s) (c) ~a+(aq) + C1-(aq) + NaCl(s) (d) ~a+(a~) + NOs-(aq) -, NaN03(s) (e) ~a+(aq) + c 12-(aq) Na2C l(s)
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$+a I- #€I.r~*/Ir-ol #I&. g R*3g&[g%%+lB+$% 8. Ammonia is prepared industrially by the reaction N2(g) + 3H2(g) * 2NH3(g) For the reaction, LVf = -92.2 kJ and K (at 25 OC) = 4.0 x lo8. When the temperature of the reaction is increased to 500 OC, which of the following is true? (a) K for the reaction will be larger at 500 OC than at 25 OC (b) At equilibrium, more NH3 is present at 500 "C than at 25 "C (c) The reaction of N2 with H2 to form ammonia is endothermic (d) Product formation (at equilibrium) is not favored as the temperature is raised , (e) None of the above is true 9. The conjugate acid and conjugate base of bicarbonate ion, HC03-, are, respectively: (a) H~O+ and OH- (b) H~O' and ~03" (c) H2C03 and OH (d) ~03~- and H2C03 (e) H2C03 and ~0~~- 10. Equal volume of 0.1 M HCl and 0.1 M HC2H302 are titrated with 0.1 M NaOH. Which of the following would be equal for both titrations?
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9501 - 32 1>$I b R$ F ~ l l Sodium oxide(Na20 crystallizes...

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