SCH4U: End of Year Review

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1 SCH4U: End f Year Review Unit 1: Energy and Rates 2 1) When 13.4 g f ammnium chlride disslve int 2.00x10 g f water the temperature changes frm 20.0 C t 15.3 C. Determine the mlar enthalpy f slutin f ammnium chlride, write a balanced thermchemical equatin fr the reactin and sketch an enthalpy diagram fr this reactin. (Ans: kj/ml) 2) The fllwing chemical reactin ccurs in a car battery: Pb(s) + PbO 2(s) + 2H2SO 4(aq) 2PbSO 4(s) + 2H2O(l) a) Given the fllwing enthalpy f frmatin values, calculate the enthalpy f reactin fr the abve reactin PbO 2(s) = -227 kj/ml PbSO 4(s) = kj/ml H2SO 4(aq) = kj/ml H2O(l) = kj/ml Answer = kj b) If it takes 39.5 kj t start yur car, what mass f lead (II) sulphate is prduced when starting the car? (Ans: 65.5 g) 3) The cmbustin f ethane is illustrated by the fllwing equatin: 2C H (g) + 7O (g) 4CO (g) + 6H O(g) a) Shw hw the fllwing equatins can be cmbined using Hess s Law t determine the enthaly f cmbustin f ethane (Ans: kj) 1) C2H 4(g) + 3O 2(g) 2CO 2(g) + 2H2O(g) ÄH = kj 2) C2H 4(g) + H 2(g) C2H 6(g) ÄH = kj 3) H (g) + ½ O (g) H O(g) ÄH = kj b) If yu wish t burn ethane as a fuel t heat g f water frm 12.5 C t C, hw many mles f ethane will be required? (Ans: 0.13 ml) 4) Page in yur text: Questins: 13, 14, 15, 16, 18 Unit 2: Chemical Equilibrium a) Intrductin t Equilibrium 1) Frm yur text: Page 457 Questins: 1-4, Page 465 Questins: 1,2 page 481 Questins: 1-8 b) Slubility Equilibrium 1) Cnsider the fllwing salts (text Ksp table : pg. 802) AgI AgNO3 AgCl Ag2CO3 Ag2CrO4 a) List these salts in rder f increasing slubility. b) Write the chemical equilibrium equatin fr the frmatin f an aqueus slutin f the least sluble silver salt. c) Determine the slubility in ml/l and in g/l fr the least sluble silver salt (Ans:9.2x10 ml/l, 2.2x10 g/l) d) Determine the slubility in ml/l f the least sluble silver salt in a slutin cntaining M -15 NaI(aq). (Ans: 3.4x10 ml/l) 2) Yu are given a ml sample f M silver nitrate slutin and a sdium carbnate -4 (Na2CO 3) prepared by disslving 6.4x10 g f sdium carbnate in water t frm ml f slutin. If the tw slutins are mixed at 25 C, will a precipitate f silver carbnate frm? -12 (Ans: Kt = 7.5x10 )

2 -2- c) Acid/Base Equilibrium 1) Determine the ph f the fllwing: (a) M KOH slutin. (b) M HNO 3 slutin (ANS: a) ph 12.4 b) ph 1.1) 2) Nictinic acid is a weak mnprtic rganic acid with the frmula C6H4NCOOH. a) Write the equilibrium equatin fr nictinic acid in water. b) If a M slutin f nictinic acid has a ph f 3.1, determine the Ka f this acid. -5 (ANS: 1.3x10 ) 3) Cnsider the fllwing salts: KNO3 LiC6H5COO N2H5Cl LiCN NH4I a) Grup the salts int the fllwing categries: i) neutral salts, ii) acidic salts, iii) basic salts b) Fr the salts that yu classified as acidic r basic write the equilibrium reactin that will explain this prperty. 4a) What vlume f M HNO 3 is needed t titrate 30.0 ml f M NaOH t the equivalence pint? What will the ph be at this pint? (ANS: 50.0 ml, ph 7) 4b) Determine the ph f the slutin after adding 49.5 ml f HNO 3 (ANS: ph 9.97) 4c) Determine the ph f the slutin after adding 50.5 ml f HNO (ANS: ph 4.03) 5) Hydrsulphuric acid is a weak acid with a Ka = 9.1x H2S + H2O H3O + HS a) Determine the ph f a M slutin f this acid. (ANS: ph 4.6) b) What is the percent dissciatin f this acid? (ANS: 0.035%) 6) Hydrcyanic acid is a weak acid with a Ka = 4.9x HCN + H2O CN + H3O a) Determine the ph f a buffer slutin prepared using 0.25 M HCN and M NaCN. (ANS: ph 7.9) -5 b) What is the Kb f the cyanide in? (ANS: Kb= 2.0x10 ) c) Determine the ph f a 0.15 M NaCN slutin. (ANS: ph 11.2) Unit 3: Atmic Structure and Classificatin f Slids 1) Describe the cntributins f the fllwing scientists t ur current understanding f atmic structure and the quantum thery: a) Bhr b) DeBrglie c) Heisenberg d) Schrdinger e) Pauli 2) Based n the quantum mechanical mdel f the atm: a) What is an rbital? b) What is the maximum electrn carrying capacity f the fllwing energy levels: n=2, n=4 c) Describe the sublevel and rbital structure f the fllwing energy levels: n=2, n=4 3) a) Write the energy level diagram fr a neutral atm f nitrgen. b) Assign the quantum numbers t each f the electrns in yur nitrgen atm. 2+ 4) Write the electrn cnfiguratin fr the fllwing: a) a neutral atm f cbalt, b) an Fe in 3

3 -3-5) Use Lewis diagrams t draw the fllwing mlecules r ins. Once cmpleted, use the VSEPR Thery t predict the shape f each. Fr each mlecule, decide whether it is plar r nn-plar. 2- a) PCl3 b) SiF4 c) CO3 d) H2S e) XeCl f) PO g) O h) CO i) NO j) SF ) Methane and flurmethane are tw very similar mlecules, despite their similarities, there is an 86 C difference between their biling pints. Which f these tw substances wuld have the higher biling pint, explain yur answer. 7) The element idine exists as slid crystals cmpsed f I 2 mlecules. A chemist wishing t disslve idine has a chice f tw slvents; water and tetrachlrmethane. Which f these tw slvents wuld be the best chice? Explain yur answer. 8) Cnsider a mlecule f ethanal. a) What type f rbital hybridizatin is each atm in the mlecule using fr bnding? b) What gemetric arrangement wuld each f these rbitals take? c) Describe the rbital verlap that accunts fr each bnd, and specify the type f bnd frmed (sigma, pi) d) What are the bnd angles arund each carbn atm in this mlecule? 9) Cnsider the data in the fllwing table fr substances labelled A t G Substance Melting pint ( C) Biling pint ( C) Slubility in H2O Electrical cnductitvity as: slid/liquid/aq. sl. A SOLUBLE NO/NO/NO B INSOLUBLE NO/NO/NA C INSOLUBLE NO/NO/NA D INSOLUBLE YES/YES/NA E SOLUBLE NO/YES/yes F INSOLUBLE NO/NO/NA G slightly SOLUBLE NO/YES/slightly a) Classify each substance as t the type f slid it represents (ie; mlecular, metallic, inic, netwrk) b) The substances labeled A t G abve are identified in randm rder belw. Match the letter t the crrect name and explain yur reasning. Quartz, calcium xide, aluminum, methanl, sulphur, methane, ptassium chlride

4 -4- Unit 4: Organic Chemistry 1) Draw the structural frmula fr the fllwing cmpunds: a) N,N-dimethyl-2-pentanamine b) 3-ethylcyclhexene c) methylprpanal d) 4-chlr-3-methyl-1-hexyne e) 2-ethxyprpane f) prpylbenzate g) N-ethylprpanamide h) 2,3-diflurbutanic acid i) cyclbutanne j) 2-methyl-3-hexanl k) phenyl methanate l) 2,4-hexadiene 2) Name the fllwing rganic cmpunds: 3) Cmplete the fllwing chemical reactins by naming and drawing the mlecular frmula the rganic prduct(s). Assume all required cnditins are available fr each reactin. a) 3-methyl-1-butyne + 2Cl 2 b) methane + excess O2 c) 2-methyl-3-pentanl + KMnO4 d) methylprpene + HBr e) 2-methylbutanal + KMnO 4 f) cyclpentene + H2O (H2SO 4 catalyst) g) dimethyl-1,3-prpandil + KMnO h) ethanic acid + phenl 4 4) Cnsider the fllwing rganic cmpunds: prpanne, 2-prpanl, 2-chlrprpane, prpanic acid, prpane a) Fr each cmpund, identify the type f intermlecular frces acting between mlecules b) Rate the slubility f each cmpund in water as: insluble, slightly sluble r very sluble c) Arrange the cmpunds in rder f increasing biling pint.

5 -5- Unit 5: Electrchemistry 1) Cnsider the fllwing electrchemical cells. Fr each, write the crrect xidatin and reductin half-reactins and determine the verall cell reactin and the standard cell ptential. Identify the cathde and ande in each cell. A) Zn Zn Cl Cl B) Pb Pb Na Na C) Au Au Ag Ag (ANS: E = (A) 2.12 V (B) 2.58 V (C) 0.70 V) cell 2) Draw and label a diagram f the fllwing electrchemical cell. Include in yur diagram a salt bridge, label each electrde, shw the directin f electrn flw determine the verall cell reactin and calculate the standard cell ptential. (ANS: E = 3.18V) cell 2+ + Mg Mg Ag Ag 3) Balance the fllwing redx reactins by the methd indicated: b) half-reactin methd in acidic slutin: - 2+ MnO + H C O Mn + CO a) half-reactin methd in basic slutin: Cr(OH) + BrO CrO + Br c) xidatin number methd: K + KNO 3 N 2 + K2O