AQA A LEVEL Chemistry QUESTIONS AND ANSWERS LATEST TOP SCORE.

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AQA A LEVEL Chemistry QUESTIONS
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AND ANSWERS LATEST TOP SCORE.
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Relative xatomic xmass x- x x x xANS.The xaverage xmass xof xan xatom xof xan xelement,
xrelative xto x
x
1/12th xof xthe xmass xof xan xatom xof xCarbon-
12
x

Relative xmolecular xmass x- x x x x ANS.Average xmass xof xa xmolecule xcompared xto
x1/12th xof x
x
the xmass xof xa xcarbon-12
xatom
x

The xAvogradro xconstant x- x x x xANS.the xnumber xof xparticles xin xa xmole x
x

ideal xgas xequation x- x x x xANS.pV x= xnRT x
x

empirical xformula x- x x x x ANS.the xsimplest xwhole xnumber xratio xof xatoms xof xeach
xelement xin x
x
a
xcompound
x



percentage xatom xeconomy x- xANS.(Mass xof xdesired xproduct/total xmass xof xreactants)
x x x
xx x
x
100
x

ionic xbonding x- x x x xANS.the xelectrostatic xattraction xbetween xoppositely xcharged xions
xin xa x
x
lattice
x

covalent xbond x- x x x xANS.a xshared xpair xof xelectrons xbetween xnon-metal xelements x
x

co-ordinate xbond x- x x x x ANS.a xshared xpair xof xelectrons xwhere xboth xelectrons xare
xsupplied x
x
by xone

xatom
x

, repulsion xin xshapes xof xmolecules x- x x x xANS.Lone xpair-lone xpair x> xlone xpair-bonding
xpair x> x
x
bonding xpair-bonding

xpair
x

electronegativity x- x x x xANS.the xpower xof xan xatom xto xattract xthe xpair xof xelectrons
xin xa x
x
covalent
xbond
x

hess' xlaw x- x x x xANS.Total xenthalpy xchange xfor xa xreaction xis xindependent xof xthe
xroute x
x
chosen
x

mean xbond xenthalpy x- x x x xANS.The xenergy xrequired xto xbreak xa xcovalent xbond
xinto x
x
gaseous xatoms xaveraged xover xdifferent
xmolecules
x

Bonds xbroken x- xbonds xmade x
x

activation xenergy x- x x x x ANS.The xminimum xamount xof xenergy xneeded xto xstart xa
xchemical x
x
reaction
x

catalyst x- x x x xANS.A xsubstance xthat xincreases xthe xrate xof xa xchemical xreaction
xwithout xbeing xchanged xby xproviding xan xalternative xreaction xpathway xby xlowering

xactivation xenergy x
x

Le xChatelier's xprinciple x- x x x xANS.When xa xsystem xin xdynamic xequilibrium xis
xsubjected xto x
x
change, xthe xposition xof xequilibrium xwill xshift xto xoppose xthe
xchange.
x

oxidising xagents x- x x x xANS.electron xacceptors x
x

reducing xagents x- x x x xANS.electron xdonors x
x
x
Enthalpy xof xformation x- x x x xANS.Enthalpy xchange xwhen xone xmole xof xa
xcompound xis


formed xfrom xits xconstituent xelements xunder xstandard xconditions xin xtheir xstandard
xstates
x

Enthalpy xof xatomization x- x x x xANS.The xenergy xrequired xto xproduce xone xmole xof
xgaseous x
x
atoms xfrom xan xelement xin xits xstandard
xstate
x