IJSO Training: Atoms and Molecules - edb.gov.hk ?· Exercise (Module: Atoms and Molecules) IJSO Training:…

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Exercise(Module:AtomsandMolecules)IJSOTraining:AtomsandMoleculesExercise1. Give2examplesforeachofthefollowing:(a) Elements(b) Compounds(c) Ioniccompoundswithmonoatomicionsonly(d) Ioniccompoundswithpolyatomicions(e) Covalentcompounds(f) Compoundscapableof forminghydrogenbond(g) Gaseouselements(h) Liquidelements(i) Elementsthatformstableionsof+1charge(j) Elementsthatformstableionsof+2charge(k) Elementsthatformstableionsof 1charge(l) Elementsthatformstableionsof 2charge(m) Elementsthatformstablemonoatomicmolecules(n) Elements thatformstablediatomicmolecules2. Whichofthefollowingis/aregoodconductor(s)ofelectricity atroomtemperature?(a) Aluminium(b) Iodine(c) Phosphorus(d) Sulphur(e) Carbon(graphite)(f) Mercury(g) Sodiumchloride3. Whichofthefollowingis/aregoodconductor(s)ofelectricityinmoltenstate?(a) Calcium(b) Sodiumchloride(c) Sugar(d) Iodine(e) Sulphur(f) LeadbromideExercise(Module:AtomsandMolecules)4. Whichofthefollowinghas/havesimilarchemicalpropertiesassodium?(a) Magnesium(b) Cesium(c) Lithium(d) Hydrogen(e) Calcium5. Whichelementhasthelargestatomicradius?(a) Na(b) Mg(c) K(d) Al6. Whichelementhasthehighestmeltingpoint?(a) Sodium(b) Magnesium(c) Potassium(d) Calcium7. Whichelementishardest?(a) Phosphorus(b) Sodium(c) Magnesium(d) Chromium8. WhoproposedthePlumPuddingAtomicModel?(a) JohnDalton(b) J.J.Thomson(c) D.I.Mendeleev(d) E.RutherfordExercise(Module:AtomsandMolecules)9. Magnesiumhasthreestableisotopes,24Mg,25Mgand26Mg. Theiratomicmassesandnaturalabundancesareshownbelow. Calculatetherelativeatomicmassofmagnesium.Isotope Atomicmass(au) Naturalabundance(%)24Mg 23.9850 78.9925Mg 24.9858 10.0026Mg 25.9826 11.0110. Strontiumhasfourstableisotopes,84Sr,86Sr,87Sr,and88Sr. Theiratomicmassesandnaturalabundancesareshownbelow. Calculatetherelativeatomicmassof strontium.Isotope Atomicmass(au) Naturalabundance(%)84Sr 83.9134 0.5686Sr 85.9093 9.8687Sr 86.9089 7.0088Sr 87.9056 82.5811. Givethenumbersof protons,neutronsandelectronsthatpresentin thefollowingspecies.Species No.ofprotons No.ofneutrons No.ofelectrons(a)24Mg2+(b)37Cl(c)40Ca2+(d)CO32(e)SO42Considerthemostabundantisotopesforitem(d)and(e)12. Anelementformsstable2+ionsthathavethesameelectronconfigurationasargon. Whatistheelement?13. Givetheelectron arrangements ofthefollowingelements:(a) Chlorine(atomicnumber17)(b) Calcium(atomicnumber20)(c) Nickel(atomicnumber28)(d) Zinc(atomicnumber30)(e) Arsenic(atomicnumber33)(f) Bromine(atomicnumber35)Exercise(Module:AtomsandMolecules)14. Balancethefollowingchemicalequations:(a) Pb(NO3)2 + NaCl PbCl2 + NaNO3(b) C2H5OH + O2 H2O + CO2(c) CCl4 + SbF3 CCl2F2 + SbCl3(Advancedexercisesbalancingredoxreaction thetotalchargesonbothsidesmustalsobebalanced)(d) MnO4 + Fe2+ + H+ Mn2+ + Fe3+ + H2O(e) MnO4 + C2O4 + H+ Mn2+ + CO2 + H2O15. CalculatethevolumeofCO2producedfrom burring14mLofC2H5OH(ethanol).Assumethegasvolumewasmeasuredat25oCand1atm.(Ethanol:density=0.789gcm3,MW =46.0688)16. Howmanyoxygenatomsarepresentin12.5gofcalciumcarbonate?17. WhatisthemassofH2Oproducedfromthecombustion of15gofCH4?18. CalculatethevolumeofCO2producedfromthecombustion of1.000kgofgasoline?(assumingthatthegasolineiscomposedof100%octaneC8H18,andthegasvolumeismeasuredat25oCand1atm)19. WhatisthevolumeofCO2producedfromthereactionof4.5gofCaCO3withexcessacid? Assumethegasvolumewasmeasuredat25oCand1atm.20. WhatisthevolumeofH2producedfromthereactionof2.4gofsodiummetalwith water? Assumethegasvolumewasmeasuredat25oCand1atm.Exercise(Module:AtomsandMolecules)21. Shownbelowisthechemicalstructureofacommondrug aspirin. Givethenumberof:HCHCCHCHCCOCOCH3OHO(a) bonds(b) bonds(c) sp3hybridizedatoms(d) sp2hybridizedatoms(e) lonepairelectrons(f) carbonatomshavingthetrigonalplanargeometry(g) atomshavingthetetrahedralgeometry22. Whichofthefollowingcompoundshassphybridizedcarbonatom?(a) H2C=CH2(b) H2C=O(c) CO2(d) CH423. BrieflyexplainwhyBF3hasatrigonalplanarstructurewhileBF4hasatetrahedralstructure.(hint:considerthehybridizationoftheboronatom)24. WhichofthefollowingcompoundshastheshortestCHbond?(a) CH4(b) H2C=CH2(c) HCCH(d) H2C=O25. Whichofthefollowingelementsformscolouredions?(a) Aluminium(b) Nickel(c) Cesium(d) LeadExercise(Module:AtomsandMolecules)26. Whichelementhasthehighestelectronegativity?(a) Fluorine(b) Oxygen(c) Bromine(d) Nitrogen27. Whichofthefollowingtypeofintermolecularinteractionsarepresentinammonia?(a) hydrogenbonding(b) dipoledipoleinteraction(c) iondipoleinteraction(d) induceddipoleinduceddipoleinteraction. TheEnd