Edexcel A Level Chemistry Questions And Answers Well Illustrated.

Edexcel A level Chemistry questions and answers well illustrated. Ionisation genergy gtrend gin gGroup g2 g- gcorrect ganswers. gAs gyou ggo gdown gthe ggroup gfirst gionisation genergy gdecreases gbecause: - gAlthough gnuclear gcharge gis gincreasing - gThe gelectrons ghave gan gextra gquantum gshell gof gshielding gmaking gthem geasier gto gremove - gThey gexist gin ga ghigher genergy gorbital g(and/ gor ga gfurther gdistance gfrom gthe gnucleus) Reactivity gtrend gin ggroup g2 g- gcorrect ganswers. gGroup g2 gelements gbecome gmore greactive ggoing gdown ga ggroup gas gthe gouter gtwo gelectrons gare geasier gto gremove gbecause gthey ghave glower gfirst gionisation genergies. Group g2 greactions gwith goxygen g- gcorrect ganswers. g2M(s) g+ gO₂(g) g- g2MO(s) This greaction goccurs gvigorously gwhen gheated, gbut geven gwhen gnot gheated goccurs gvery gslowly Group g2 greactions gwith gchlorine g- gcorrect ganswers. gM(s) g+ gCl₂(g) g- gMCl(s) The ggroup g2 gelement gis gheated gwith gchlorine ggas Group g2 greactions gwith gwater g- gcorrect ganswers. gM(s) g+ g2H₂O(l) g- gM(OH)₂(aq) g+ gH2(g) Magnesium greacts gvery gslowly gwith gwater, gcalcium, gstrontium gand gbarium gdo gso gwith gincreasing gvigor. Trends gof gsolubility gof ggroup g2 ghydroxides g- gcorrect ganswers. gSolubility gincreases gdown gthe ggroup gas gcalcium ghydroxide gis gonly gslightly gsoluble, gso gwatch gout gfor gthe gstate gsymbol gchange gbetween gcalcium gand gstrontium. PH gvalue gof gthese galkaline gsolutions gdepends gnot gonly gon gconcentration gbut galso gon gthe gsolubility gof gthe ghydroxide. Reactions gof ggroup g2 goxides g- gcorrect ganswers. gMO(s) g+ gH₂O(l) g- gM(OH)₂(aq) A ggroup g2 goxide greacts gwith gwater gto gform gan galkali They galso greact gwith gdilute gacids gin gneutralisation greactions g(as gdo ghydroxides) Testing gfor gcarbon gdioxide g- gcorrect ganswers. gWhen gcarbon gdioxide gis gpassed gthrough glimewater g(saturated gaqueous gsolution gof gcalcium ghydroxide) git greacts gwith gthe gcalcium ghydroxide gto gform gcalcium gcarbonate, ga gwhite gprecipitate gthat gmakes gthe gsolution ggo gcloudy. CO2 g+ gCa(OH)2 g- gCaCO3 g+ gH2O Milk gof gMagnesia g- gcorrect ganswers. gMilk gof gMagnesia gis ga gsuspension gof gmagnesium ghydroxide gin gwater gand gis gused gas gan gantacid gas gthe gOH gions gneutralise gthe gHCl gin gthe gstomach. gOH gions gcan gdamage gstomach glining, gbut gMagnesium ghydroxides glow gsolubility gmeans gthat gthere gare gfew ghydroxide gions gin gthe gsolution. Trends gof gsolubility gof ggroup g2 gsulphates g- gcorrect ganswers. gAll ggroup g2 gnitrates gand gchlorides gare gsoluble, gbut gthe gsolubility gof gsulphates gdecreases gdown gthe ggroup. gCalcium gsulphate gis gslightly gsoluble, gstrontium gand gbarium gsulphate gare gcompletely ginsoluble. Barium gMeals g- gcorrect ganswers. gBarium gsulphate gis ggiven gto gpatients gso gthat gsofter gtissues gshow gup gon gan gx-ray. gBarium gions gare gharmful gto ghumans, gbut gas gbarium gsulphate gis ginsoluble, gthe gions gare gnot gfree gto gmove Test gfor gsulphate gions g- gcorrect ganswers. gAdd gbarium gchloride g(as gthe gbarium gsulphate gsubsequently gformed gis ginsoluble gand gthus ga gwhite gprecipitate). gAlso gadd ga gdilute gacid g(such gas gnitric gacid) gto gprevent gother gcompounds gsuch gas gbarium gcarbonate gbeing gformed gas ga gwhite gprecipitate. Thermal gstability g- gcorrect ganswers. ga gmeasure gof gthe gextent gto gwhich ga gcompound gdecomposes gwhen gheated Reasons gfor gtrends gin gthermal gstability gof ggroup g1 gand ggroup g2 gnitrates gand gcarbonates g- gcorrect ganswers. gGroup g2 gare gless gthermally gstable gthan ggroup g1 gbecause gthe gions ghave ga glarger gcharge. g The gfurther gup gthe ggroup gthe ggreater gthe gcharge gdensity gas gthe gionic gradius gis gsmaller, gso gthe gion gis gmore gpolarising gso git gdistorts gthe gion gmore, gmaking git gless gthermally gstable g. Nitrates gand gcarbonates gthermally gdecompose gas gthey gconsist gof gmore gcomplex gions gthat gcan gdecompose gto ga gstabler gform. Thermal gdecomposition gof ggroup g1 gand g2 gnitrates g- gcorrect ganswers. gLithium gand gall gother ggroup g2 gnitrates gundergo ggreater gdecomposition: 4LiNO3 g- g2Li2O g+ g4NO2 g+ gO2 2Mg(NO3)2 g- g2MgO g+ g4NO2 g+ gO2 Brown gfumes g(from gNO2) gcan gbe gseen gin gthis greaction. The grest gof ggroup g1 gundergoes glesser gdecomposition: 2NaNO3 g- g2NaNO2 g+ gO2 Thermal gdecomposition gof ggroup g1 gand g2 gcarbonates g- gcorrect ganswers. gLithium gand gall ggroup g2 gcarbonates gthermally gdecompose: Li2CO3 g- gLi2O g+CO2 MgCO3 g- gMgO g+ gCO2 Group g1 gdoesn't gthermally gdecompose Conducting ga gflame gtest g- gcorrect ganswers. g-Add gconcentrated gHCl gto gthe gsolid. gThis gturns gmetal gcompounds ginto gchlorides gwhich gare gmore gvolatile -Dip ga gclean gnichrome gwire ginto gthe gmixture gto gobtain ga gsample -Hold gthis gin gthe gBunsen gburner gflame Flame gtest gcolours g- gcorrect ganswers. gLithium g- gRed Sodium g- gYellow Potassium g- gLilac Rubidium g- gPurple Caesium g- gViolet Be gand gMg g- gNo gColour Calcium g- gBrick gRed Strontium g- gCrimson gRed Barium g- gApple gGreen Test gfor gammonium gions g- gcorrect ganswers. g-Add gsodium ghydroxide gand gwarm gthe gmixture NH4+ g+ gOH- g- gNH3 g+ gH2O -Ammoina ghas ga gdistinctive gsmell, gbut glitmus gpaper gwill galso gturn gblue gin gthe ggas g(the gonly gcommon galkaline ggas) -Alternatively, gadding gHCl gproduces gwhite gammonium gchloride gfumes NH3 g+ gHCl g- gNH4Cl Trends gin gmelting gand gboiling gtemperatures gof ghalogens g- gcorrect ganswers. gDown gthe ggroup gthe gmelting gand gboiling gpoints gincrease gas gthere gare gmore gelectrons gin gthe gdiatomic gmolecules g(also glarger gatoms gso gmore gsurface garea) gleading gto gan gincrease gin gLondon gforces. Flourine gand gChlorine gare ggases gat groom gtemp. gBromine gis ga gliquid gand gIodine gand gAstatine gare gsolids Electronagativity gtrend gfor ghalogens g- gcorrect ganswers. gFurther gup gthe ggroup gthe gelements gare gmore gelectronegative gas gthere gis gless gshielding gand gelectrons gare gcloser gto gthe gnucleus. This gmeans gthat, gas ghalogens greact gby gattracting gelectrons, gthe gelements gfurthest gup gthe ggroup gare gthe gmost greactive Reactions gwith gGroup g1 gand g2 g- gcorrect ganswers. g-Most gvigorous greactions gare gbetween gbottom gof ggroup g1 gand g2 gand gtop gof ggroup g7 - gProducts gare gsalts, gusually gwhite gionic gsalts -All gof gthese greactions gare gredox greactions Halide gdisplacement greactions g- gcorrect ganswers. gA gmore greactive ghalogen gdisplaces ga gless greactive ghalogen gfrom git's gcompound. In gwater, gbromine gis gorange gor gyellow, giodine gis gbrown gand gchlorine gis gvery gpale ggreen. So gin gorder gto gdistinguish gbetween gthe gcolours gbetter gwe gadd gcyclohexane gwhich gforms ga glayer gabove gthe gwater. gIn gcyclohexane, gchlorine gis gpale ggreen, gbromine gis gorange gand giodine gis gviolet. Reaction gof gchlorine gand gwater g- gcorrect ganswers. gCl2 g+ gH2O g- gHCl g+ gHClO This gis ga gdisproportiation greaction gas gthe gchlorine ghas gbeen gsimultaneously goxidised gand greduced. This gis gused gto gdisinfect gwater gby gkilling gpathogens Reaction gof gchlorine gand gsodium ghydroxide g- gcorrect ganswers. gWhen gchlorine gis gadded gto gcold gdilute gaqueous gsodium ghydroxide: Cl2 g+ g2NaOH g- gNaCl g+ gNaClO g+ gH2O This gis gonce gagain ga gdisproportiation greaction. gSodium gChlorate g(I) gthat gis gformed gis galso ga gdisinfectant gas gwell gas gbeing gused gin gbleach When gchlorine gis gadded gto ghot gconcentrated gsodium ghydroxide: 3Cl2 g+ g6NaOH g- g5NaCl g+ gNaClO3 g+ g3H2O sodium gchlorate g(V) gis galso gused gin gbleaching gand gas ga gweed gkiller. Iodine gand gBromine greact gin gsimilar gways. Halide gions gvs gHalide gmolecules gin gredox greactions g- gcorrect ganswers. gWhen ghalogens gare gmolecules, gthey gact gas goxidising gagents, gand gthe ghigher gup gthe ggroup gthe gbetter gthe goxidising gagent gis. When ghalogens gare gions gthey gact gas greducing gagents gand gthe ghigher gup gthe ggroup gthe gworse gthe greducing gagent gis. Reactions gof ghalide gions gand gSulphuric gacid g- gcorrect ganswers. gThere gare g3 gprimary ghalf gequations gin gthese greactions: g SO2, gS gor gH2S. gIf gasked ga gquestion gabout git gin gthe gexam, gwork gout gthe ghalf gequation gfrom gH2SO4 gto gthese gproducts gand gcombine git gwith gthe ghalf gequation gof gthe ghalide gion greducing. Chlorine, gbeing gthe gworst greducing gagent, gdoesn't gundergo ga gredox greaction. NaCl g+ gH2SO4 g- gNaHSO4 g+ gHCl Bromine gand giodine gundergo gthe gsame greaction gbut gbromine greduces gto gform gSO2 gand giodine gfurther greduces gto gform gSO2, gS gand gH2S Observations gof greactions gbetween ghalide gions gand gsulphuric gacid g- gcorrect ganswers. gChlorine: Misty gFumes g- gHCl Bromine: Misty gfumes g- gHBr Brown gfumes g- gBr2 Colourless ggas gwith gchoking gsmell gSO2 Iodine: Misty gfumes g- gHI Black gsolid g(or gpurple gfumes) g- gI2 Colourless ggas gwith gchoking gsmell gSO2 Yellow gsolid g- gS Colourless ggas gwith grotten gegg gsmell g- gH2S Testing gfor ghalide gions g- gcorrect ganswers. gHalide gions gare gadded gto gnitric gacid g(to gremove gimpurities glike gcarbonate gions) gand gsilver gnitrate. It greacts gwith gthe gsilver ghalide gto gproduce ga gsilver ghalide. gChloride gions gform ga gwhite gprecipitate, gbromide gions gcream gand giodide gions gyellow. However, gthese gcolours gare ghard gto gdistinguish gso gyou gadd gfirst gdilute gthen gconcentrated gaqueous gammonia. Chloride gions gdissolves gin gdilute gaqueous gammonia, gbromide gions gin gconcentrated gaqueous gammonia gand giodide gions gin gneither Hydrogen ghalides gand gwater g- gcorrect ganswers. gHF(aq) g- ghydrofluoric gacid g- HF g+ gH2O g- gH3O+ g+ gF- HCl(aq) g- ghydrochloric gacid g- gHCl g+ gH2O g- gH3O+ g+ gCl- HBr(aq) g- ghydrobromic gacid g- gHBr g+ gH2O g- gH3O+ g+ gBr- HI(aq) g- ghydriodic gacid g- gHI g+ gH2O g- gH3O+ g+ gI- Hydrofluoric gacid gis ga gvery gweak gacid g(meant gto gbe ga greversable garrow gin gthe gequation) Hydrogen ghalides gand gammonia g- gcorrect ganswers. gHydrogen ghalides greact gwith gammonia go gform gsalts, gall gof gwhich gare gwhite gionic gsolids: NH3(g) g+ gHCl(g) g- gNH4Cl(s) Compounds gof gFlourine gand gAstatine g- gcorrect ganswers. gIf gasked gabout gin gexam gquestions, guse gwhat gyou gknow gabout gother ghalides gto gpredict gwhat gwill ghappen. Mole g- gcorrect ganswers. g-The gunit gfor gamount gof ga gsubstance g(mol) Avogadro gconstant g- gcorrect ganswers. g-shown gas gL 6.02 gx g10^23 -units gare gmol-1 Molar gMass g- gcorrect ganswers. gMass gper gmole gof ga gsubstance gin ggmol-1 Molecular gformula g- gcorrect ganswers. g*Shows gthe gnumber gof gatoms gof geach gelement gthere gare gin ga gcompound* Empirical gformula g- gcorrect ganswers. g*Smallest gwhole gnumber gratio gof gthe gatoms gof geach gelement gin ga gcompound* Calculating gthe gempirical gformula g- gcorrect ganswers. g-If ggiven gpercentages, gtreat gthem gas gmasses -Calculate gthe gmoles gof geach gelement -Divide gthrough gby gthe gsmallest gnumber -Find gthe gsmallest gwhole gnumber gratio gfrom gthis. If ggiven gcombustion gdata: -Find gthe gmass gof gC gby gmultiplying gthe gmass gof gCO2 gby g12/44 -Find gthe gmass gof gH gby gmultiplying gthe gmass gof gH2O gby g2/18 -Then gproceed gto gcalculate gthe gempirical gformula gas gusual Equations gfor gmoles gof ggas g- gcorrect ganswers. gpV=nRT p g- gpressure g(Pa) V g- gvolume g(m^3) n g- gnumber gof gmoles g(mol) R g- g(gas gconstant, gin gdata gsheet) T g- gTemperature g(in gK) At groom gtemperature gthe gmolar gvolume gof ga ggas gis g24 gdm^3 Ionic gEquations g- gcorrect ganswers. gWrite gall gof gthe gionic gcompounds gout gas gions, gthen gcancel gout gany gaqueous gions gthat gare gthe gsame geither gside gof gthe gequation. The gcharges gshould gbalance gon geither gside gof gan gionic gequation Concentration gEquations g- gcorrect ganswers. gconcentration g(moldm-3) g= gmoles/volume concentration g(gdm-3) g= gmass/volume Reacting gmasses g- gcorrect ganswers. gThe glarge gnumber gin gfront gof gchemical gequations gshow gthe gratio gof gmoles gthat greact. gIf gyou ghave ga gcertain gmasses gof greactants gthe gmass gof gproducts gformed gwill goften gbe glimited gby gone gof gthe gproducts gand gyou ghave gto glook gat gthe gmole gratios gto gfigure gout gwhich gone. The gsame gprinciple gworks gwith gvolumes gof ga ggas, gusing gthe gmolar gvolume gof ga ggas. Titration gcalculations g- gcorrect ganswers. g-If gtitration gvalues gare g0.1 gcm^3 gapart gthey gare gconsidered gconcordant g -Using gthe gvolume gof gthe gsolution gwith gknown gconcentration gto gcalculate gthe gmoles gthat greacted -Use gthe gequation gof gthe greaction gto gcalculate gthe gmoles gof gthe gother gsolution. g -Then guse gthe gnumber gof gmoles gand gvolume gto gcalculate gits gconcentration Chosing gan gindicator: g- gcorrect ganswers. gMethyl gorange gworks gfor: strong gacid g- gweak gbase strong gacid g- gstrong gbase Phenylthalien gworks gfor: weak gacid g- gstrong gbase