AQA A-LEVEL CHEMISTRY DEFINITIONS, FROM
MARK SCHEMES QUESTIONS WITH ANSWERS
2025 - 2026
Activation,Energy,,,ANS,-Minimum,energy,(1)
required,before,a,reaction,can,occur,(1)
Atomic,number,,,ANS,-Number,of,protons,in,one,atom,or,nucleus,(1)
Catalyst,,,ANS,-
A,substance,that,speeds,up,the,reaction,/,alters,the,rate,but,is,chemically,unchanged,at,the,end,/,not,used
,up
Dynamic,Equilibrium,,,ANS,-Rate,of,forward,reaction,=,rate,backward,reaction,(1)
concentration,remains,constant,(1)
Electronegativity,,,ANS,-Tendency,or,strength,or,ability,or,power,of,an,atom/element/nucleus,to
attract,bonding,pair,of,electrons,(1)
In,a,covalent,bond,(1)
Empirical,Formula,,,ANS,-(simplest),ratio,of,atoms,of,each,element,in,compound,(1)
Enthalpy,Change,,,ANS,-Heat,energy,change,(1)
measured,at,constant,pressure,(1)
First,Ionisation,Energy,,,ANS,-
Enthalpy/energy,change/required,when,an,electron,is,removed,to,form,a,positive,ion,(1)
In,the,gaseous,state,(1)
Hess's,Law,,,ANS,-(The,enthalpy,change,for,a,reaction,is),independent,of,the,route,taken,(1)
MARK SCHEMES QUESTIONS WITH ANSWERS
2025 - 2026
Activation,Energy,,,ANS,-Minimum,energy,(1)
required,before,a,reaction,can,occur,(1)
Atomic,number,,,ANS,-Number,of,protons,in,one,atom,or,nucleus,(1)
Catalyst,,,ANS,-
A,substance,that,speeds,up,the,reaction,/,alters,the,rate,but,is,chemically,unchanged,at,the,end,/,not,used
,up
Dynamic,Equilibrium,,,ANS,-Rate,of,forward,reaction,=,rate,backward,reaction,(1)
concentration,remains,constant,(1)
Electronegativity,,,ANS,-Tendency,or,strength,or,ability,or,power,of,an,atom/element/nucleus,to
attract,bonding,pair,of,electrons,(1)
In,a,covalent,bond,(1)
Empirical,Formula,,,ANS,-(simplest),ratio,of,atoms,of,each,element,in,compound,(1)
Enthalpy,Change,,,ANS,-Heat,energy,change,(1)
measured,at,constant,pressure,(1)
First,Ionisation,Energy,,,ANS,-
Enthalpy/energy,change/required,when,an,electron,is,removed,to,form,a,positive,ion,(1)
In,the,gaseous,state,(1)
Hess's,Law,,,ANS,-(The,enthalpy,change,for,a,reaction,is),independent,of,the,route,taken,(1)
