OCR CHEMISTRY ALEVEL PAPER 1

OCR CHEMISTRY ALEVEL PAPER 1


ATOMICmNUMBERm-mthemnumbermofmprotonsminmthemnucleusmofmanmatom

MASSmNUMBERm-
mthemtotalmnumbermofmprotonsmandmneutronsminmthemnucleusmofmanmatom

ISOTOPESm-mAtomsmofmthemsamemelementmwithmdifferentmnumbersmofmneutrons

ATOMICmORBITALm-
mAmregionmaroundmthemnucleusmthatmcanmholdmupmtomtwomelectrons,mwith
oppositemspins.

p-BLOCKmELEMENTm-mElementmwhichmhasmthemhighestmenergymelectronminmampmsub-
shellm(ormpmorbital)
(Appliesmtomanymelement;ms-,mp-,md-mormf-block)

FIRSTmIONISATIONmENERGYm-
mThemenergymrequiredmtomremovemonemelectronmfrommeachmatomminmonemmolemofmgas
eousmatomsmtomformmonemmolemofmgaseousm1+mions

SUCCESSIVEmIONISATIONmENERGYm-
mAmmeasuremofmthemenergymrequiredmtomremovemeachmelectronminmturn

MOLARmMASSm-mthemmassminmgramsmofmonemmolemofmamsubstance

RELATIVEmISOTOPICmMASSm-
mThemmassmofmanmatommofmanmisotopemcomparedmwithm1/12thmofmthemmassmofmanma
tommofmcarbon-12

RELATIVEmATOMICmMASSm-
mThemweightedmmeanmmassmofmanmatommofmanmelementmcomparedmwithmone-
twelfthmofmthemmassmofmanmatommofmcarbon-12.

AVOGADRO'SmCONSTANTm-
mThemnumbermofmparticlesmpermmolemofmamsubstancem(6.02mxm1023mmol-1)

MOLARmGASmVOLUMEm-
mThemgasmvolumempermmolemofmamsubstance.mThismism24.0mdm3mol-
1matmroommtemperaturemandmpressurem(RTP).

EMPIRICALmFORMULAm-
mThemsimplestmwholemnumbermratiomofmatomsmofmeachmelementmpresentminmamcompoun
d.

MOLECULARmFORMULAm-
mThemactualmnumbermandmtypemofmatomsmofmeachmelementminmammolecule.

WATERmOFmCRYSTALLISATIONm-
mWatermmoleculesmthatmarembondedmintomamcrystallinemstructuremofmamcompound

ANHYDROUSm-mdescribesmamsubstancemthatmdoesmnotmcontainmwater

, HYDRATEDm-mWhenmwatermofmcrystallisationmismpresentminmamcrystalmcompound.

ELECTRONmPAIRmREPULSIONmTHEORYm-
m•mThemshapemofmsimplemcovalentmmoleculesmandmionsmaremdeterminedmbymthemnumbe
rm&mtypemofmelectronmpairsmaroundmthemcentralmatom.
•mElectronmpairsmrepelmonemanothermasmfarmapartmasmpossible
•mLonempairsmofmelectronsmrepelmmoremstronglymthanmbondmpairsmofmelectrons

METALLICmBONDINGm-
mThemstrongmelectrostaticmattractionmbetweenmmetalmcationsm(positivemions)mandmdelocalis
edmelectronsm(inmamgiantmmetallicmlatticemstructure).

PERIODICITYm-
mthemrepeatingmpatternmofmchemicalmandmphysicalmpropertiesmacrossmdifferentmperiods.

ENTHALPYmCHANGEm-
mThemamountmofmheatmreleasedm(ormabsorbed)mbymamchemicalmreaction,mcarriedmoutmat
mconstantmpressure.mUnits:mkJmmol-1.

EXOTHERMICmREACTIONm-
mAmreactionmwheremheatmenergymismreleasedmtomthemsurroundings.m(ΔHmismnegative)

ENDOTHERMICmREACTIONm-
mAmreactionmwheremheatmenergymismabsorbedmfrommthemsurroundings.m(ΔHmismpositive)

HESS'mLAWm-
mIfmamreactionmcanmtakemplacembymmoremthanmonemroutemandmtheminitialmandmfinalmco
nditionsmaremthemsame,mthemtotalmenthalpymchangemismthemsamemformeachmroute.

AVERAGEmBONDmENTHALPYm-
mThemaveragementhalpymchangemformthembreakingmofmonemmolemofmbondsminmgaseousm
moleculesm(bymhomolyticmfission).

STANDARDmCONDITIONSm-m•mTemperaturem=m25moCm(298mK)
•mPressuremofmgasesm=m1matmm(100mkPa)
•mConcentrationmofm(aq)msolutionsm=m1.00mmoldm-3

STANDARDmENTHALPYmCHANGEmOFmNEUTRALISATIONm-
mthementhalpymchangemwhenmonemmolemofmwatermismformedmfrommthemreactionmofman
macidmwithmanmalkalimundermstandardmconditions

STANDARDmENTHALPYmCHANGEmOFmFORMATIONm-
mThementhalpymchangemthatmtakesmplacemwhenmonemmolemofmamcompoundmismformedmf
rommitsmconstituentmelementsminmtheirmstandardmstatesmundermstandardmconditions.

STANDARDmENTHALPYmCHANGEmOFmCOMBUSTIONm-
mthementhalpymchangemwhenm1mmolemofmamsubstancemismcompletelymburnedminmoxygen
mundermstandardmconditions.

RATEmOFmREACTIONm-
mthemchangeminmconcentrationmofmamreactantmormproductmpermunitmtime

ACTIVATIONmENERGYm-
mThemminimummenergymrequiredmformamreactionmtomtakemplace,mbymthembreakingmofmbo
ndsminmthemreactants.