Sample Examination II Questions 1. Identify the substance that will hydrolyze to form a basic solution. a. 2. 3. a. [SiO4] n4n- d. [SiO3] n2n- d. BiCl3 83 b. [Si4O11] 6- c. [Si6O18]12- is present in CaH2. can be considered a bonding m.o. that encompasses three atoms. is present in BF3. describes the bonding in boron halides such as B2Cl4. OL3S b. O4L3S O2L3S2 c. O8L6S Mg2Si reacts with HCl(aq ) to give SiCl4 (g) and MgH2(s ). A silicone contains organic molecules attached to a (-Si-O-Si-O)n backbone. Silanes burn spontaneously when they are exposed to air. During discharge, Pb(s ) is oxidized to PbSO4(s ) in the Pb storage battery. The substance whose conductivity should increase with increasing temperature is a. NaF b. SrH2 c. Mg3N2 d. GaAs The compound that will produce an acidic solution because of hydrolysis is a. 8. CrBr3 24 Identify the INCORRECT statement about the group 14 elements. b. c. d. 7. c. Express the empirical formula of the compound in terms of O (open), L (large dark) and S (small dark) atoms: a. 6. Ba(NH2)2 A three-center, two-electron bond a. d. 5. b. The composition of the silicate illustrated in which each apex represents a O atom and an Si atom is in the center of each tetrahedron is best described as a. b. c. d. 4. NH4ClO3 NaCl b. Al2Br6 c. Al2O3 d. BaI2 e. Na2O2 Which of the following solids when added to water will not produce a basic solution? a. Na b. CaH2 c. Mg d. LiH 9. Which reaction will proceed as written? (All are balanced.) (See the activity series on the bottom of the page) a. b. c. d. 10. 12. an insulator. an intrinsic semiconductor. an n-type semiconductor. 2. b. d. a conductor. a p-type semiconductor. BaCl2 3. 1. BaCO3 a. c. Only one is soluble. Only three are soluble. AgNO3 47 b. d. 4. Pb(C2H3O2)2 Only two are soluble. All are soluble. A solution containing Na2SO4(aq ) is electrolyzed in an electrolysis cell. b. H2(g ) forms at the anode. Na( ) forms at the cathode. d. Na+ ions migrate to the anode. O2(g ) forms at the cathode. [SO4]2- ions migrate to the anode. Cs has the smallest ∆HI.E. and smallest ∆Hsublimation of the group 1 elements, yet Li(s ) is the strongest reducing agent because 55 a. b. c. d. 14. 2 KH(s ) + K2SO4(s ). CuS(s ) + Pb(s ). 2 Cl3Al→BF3(s ). 2 Na+ + 2 [Al(OH2)2(OH)4]1- + 3 H2(g ). Consider the water solubility of the four compounds: a. c. e. 13. → → → → The darkened area represents the valence band. The material is a. c. e. 11. 4 K(s ) + H2SO4( ) PbS(s ) + Cu(s ) (in H2 O) Al2Cl6(s ) + 2 BF3(g ) 2 Al(s ) + 2 NaOH(aq ) + 10 H2O lithium is a better Lewis base than the other elements. lithium’s small size enables it to come close to other ions and transfer an electron. Li+(g ) has an exceedingly high hydration energy. Li(g ) has the highest electron affinity, ∆HE.A.. Identify a Lewis acid-base reaction. a. b. c. d. KOH(aq ) + HCl(g ) 55BaF2(s ) + BeF2(g ) 4 KO2(s ) + 2 CO2(g ) K2HPO4(aq ) + KHSO4(aq ) → → → → KCl(aq ) + H2O. Ba[BeF4](s ). 2 K2CO3(s ) + 3 O2(g ). K[H2PO4](aq ) + [SO4]2- + 2 K+. Activity series: Li > K > Ca > Na > Mg > Al > Zn > Cr > Fe > Cd > Ni > Sn > Pb > H2 > Cu > Hg > Ag -2- 15. The compound that will form when SO2(g ) is forced through powdered SrO(s ) is a. 16. c. d. SrSO4 After a brief interlude while the Al2O3 coat is penetrated, a vigorous reaction ensues. After a slow beginning white clouds of Al2Br6 come into the room. A black powder fuse initiates the reaction, which then proceeds vigorously. The reaction begins instantly with a shower of sparks. The heat produced by the reaction causes most of the CO2(s ) to sublime. Magnesium reduces the CO2(s ) to CO(g ) and forms white MgO(s ). Magnesium reacts with the BaO2(s ) to form a black powder and MgO(s ). Magnesium reduces CO2(s ) to black C(s ) and MgO(s ); most of the CO2(s ) remains. only B, Al and Ga can be oxidized to the 3+ oxidation state. the 1+ oxidation state becomes available after the 3d block is filled. the stability of the 3+ oxidation state increases as Al3+ < Ga3+ < In3+ < Tl3+. the 3+ halides, e.g., 81TlCl3, are strong Lewis bases. Reduction of Al(s ) to Al2O3 is exceedingly exothermic. After a brief induction period required to remove the oxide coat on the Al, Fe2O3 was oxidized to Fe( ). BaO2(s ) provided oxygen needed to ignite the Al and start the reaction. BaO2(s ) caused a shower of sparks to shoot between the cracks in the pot. Identify a correct statement about ’hard water.’ a. b. c. d. 21. d. A mixture of powdered Al(s ), red Fe2O3(s ), and a small amount of BaO2(s ) confined in a clay pot were ignited with a black powder fuse. Which statement is correct? a. b. 20. SrS2O3 In the group 13 s 2 p 1 elements a. b. c. d. 19. c. Powdered Mg(s ), a small amount of BaO2(s ), and a fuse are inserted into a block of solid CO2. The fuse is ignited. a. b. c. d. 18. SrS2O7 Al(s ) is dropped into Br2( ). a. b. c. d. 17. SrSO3 b. Shells of eggs boiled in hard water always crack. Temporary hard water forms when SO2(g )-saturated water passes over limestone, CaCO3(s ). Permanent hard water can be softened by boiling. Hard water that contains [HCO3]1- anions can be softened by adding Na2CO3(aq ). Identify the compound that is least likely to explode if heated intensely. a. NH4NO3 b. NH4NO2 c. -3- NH4ClO4 d. (CH3)4NI 22. Sheldon added first methyl violet and then CH3OH to Al2Cl6 dissolved in CH2Cl2. The initial yellow (acidic) solution turned blue (basic) when CH3OH was added. a. b. c. d. 23. Identify the correct statement about the group 2 family of elements. a. b. c. d. 24. palladium wire was heated to a red heat by the exothermic reaction. reaction slowed down when O2(g ) was bubbled through the ammonia. nitric oxide reacted immediately with the ammonia to give ammonium nitrite. wire cooled down when removed from the flask, but when reinserted again glowed red. Identify a Brønsted acid/base reaction. a. b. c. d. 27. White phosphorus is kept under mineral oil to protect it from air. In an excess of chlorine PCl5 results. White phosphorus does not react with air, but ignites instantly in chlorine gas. The reaction produces POCl3 in a deficiency of chlorine. In the catalytic oxidation of ammonia to nitric oxide and water, the a. b. c. d. 26. All the hydroxides, E(OH)2, are amphoteric. All the iodides, EI2, are Lewis acids. Oxide basicity increases ↓. Electronegativity increases ↓, so it is more easy to prepare the peroxide of barium (BaO2 (s) ) than of the lighter analogues. Identify the correct statement about the reaction of white phosphorus with chlorine gas. a. b. c. d. 25. The oxygen atom of CH3OH is a better Lewis base than is methyl violet. Three CH3OH reacts with ½ Al2Cl6 to form 3 CH3Cl and basic Al(OH)3. The oxygen atom of CH3OH donates electrons to the acidic methyl violet, making it basic. The hydroxyl group of CH3OH bonds to the methyl violet, making it basic. Cl2(aq ) 4 KClO3(s ) HF(l ) AgI(s ) + + + + → → H2S2O7(l ) → 2 Na2S2O3(aq ) → HCCH(g ) heat 2 HCl(g ) + KCl(s ) [H2F]+ [Ag(S2O3)2]3- 2 C(s ) + 3 KClO4(s ) + [HS2O7]1+ 4 Na+(aq ) + I1-()aq Write on the answer sheet the sum of the coefficients x and y in the balanced equation Zn(s ) + HNO3(aq ) → x Zn(NO3)2(aq ) + NO(g ) + y H2O -4-