AQA AS and A level Chemistry 300 Past Paper Topic Questions and Answers
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Course
All Chemistry units (7405)
Institution
AQA
Contains AQA AS and A level chemistry ( specification) past paper topic questions all on one document! Has over 200+ past paper topic questions organised by their topics. Answers are included which were taken directly from mark schemes.
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AQA As Chemistry Past Paper questions 7404-7405-2015 specification
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Key
ele-/e-= electron
(2)= a past paper question worth 2 marks
Blue=definitions
Physical chem
Define 1st ionisation energy: the energy required to remove 1 mol of electrons from 1 mol of gaseous atom
Relative atomic mass (Ar) the mean mass of an atom of an element, divided by 1/12 of the mean mass o
Relative molecular mass (Mr)The mean mass of a molecule of a compound, divided by 1/12 of the mean mass o
Electronegativthe power of an atom to attract the pair of electrons in a covalent bond
State a reason why the trend in first ionisation energies for the elements in G2 supports the existence of electro
Explain how ions are accelerated, seperated + detected in ToF, Mass spectrometer (4)ions acceletared by elect
Describe and compare electron impact and electrospray ionisation process in ToF(6) aElectron impact: sample
answer (continued): Electrospray ionisation: s
Define molecular ion (1) (mass spec q'n) A charged particle with the highest mass.
Give 2 reasons why the sulfur dioxide by-product is removed from the exhaust gases ( prevents acid rain; to ma
Explain the pattern in first ionisation energy (I.E) of the elements from Lithium to Neon Generally the 1st I.E incr
Energetics
enthalpy of formation (2) enthalpy change when 1 mol of substance/coompound is fromed from its elements
enthalpy of combustion the enthalpy change when one mole of substance undergoes complete combustion
enthalpy of neutralisation The enthalpy change when one mole of water is formed from its ions in dilute solut
enthalpy of reaction enthalpy change when molar amounts of reactants as stated in the equation, react
Hesses law Enthalpy change is independent of the path taken
Suggest a reason, other than incomplete combustion of heat transfer, why the students value is different from th
what do you do to the value if the reaction put a negative sign!
give 2 features of a dynamic equilibrium(2) forward and back reactions occur at the same rate; products and rea
when question talks about raising temperature what should you write ab Kinetic energy, more molecules have en
Define the term enthalpy of lattice formationEnthalpy chang
Kinetics
,Explain why the boltzmann curve starts at the origin (1) No particles have zero energy.
Explain what is meant by rate of reaction (2The rate of reaction is the change in the concentration of a reactant or
Expalin why the rate of a reaction increases when the conc of HCL increases (2) Increases the number of
how is Kc effected? (1) by temp; unaffected by pressure and catalsy
State and expalin the effect of using a catalyst on equilibrium yield (2) No effect on yeild; increases rate of rea
what is a lewis base has a lone pair of electrons and attacks a positive region ex Water moelcules are le
Oxidation and reduction -3
Give the formula of a nitrate(v) ion, which has an overall charge of -1: NO3 -1 ( it is given that the Nitrogen is +
Exceptions:
What is the oxidation no. of Hydrogen in N -1. Na= +1
What is the oxidation no. of fluorine in F2O -1 because Fluorine is more electronegative than Oxygen. So oxyge
P1 AS level questions
State which element, Mg or Al has the lower 1st I.E (3) Al; electron in 3p orbital; further from nucleus/easier to
Why does the bond enthalpy calculated in the experiment different from the data bookl Data booklet value is der
Explain how permanent dipole-dipole forces arise between hydrogen chloride moleculeDifference in electronega
Explain why F ion has is larger than Na ion? (2) Fluoride ion has (two) fewer protons; Weaker attractio
Explain why the melting point of sodium fluoride is high (2(Electrostatic) forces of attraction between oppositely
Name the type of bond that forms when HF reacts with H+ an explain how this bond is formed (2)
state why the isotopes of rhenium have the same chemical properites(1)same electron configuration;
chlorine gas is bubbles through a solution of NaI. give an observation(1) brown solution (I2)
iodine in water is brown
When haloalkanes (of Chlorine, bromine and iodine) react with silver nitrate, what is the order halogen precipitat
Compounds with the same structural formula but different
arrangements of atoms in space
Organic chemistry
Catalytic cracking catalyst & temp Zeolite catalyst and 550 celcuis
A thin layer of metals is used inside catralytic converters. Explain why a thin layer is used in this way.
Give one reason why bonds in molecules such as carbon dioxide and 1,1,1-trigluoroethane absorb infrared radia
Suggest what antibumping granules do(1) form small bubbles, less explosive bumping
Explain why more 3-bromo-3methylpentane is formed in this reaction than 2-bromo-3-methylpentane
what is an electrophile an electron defficient species
what is a nucleophile has a lone pair of electrons
what is a nitrile has a N triple bonded to it
what is an amine has a NH2 bonded to it
explain why the product is the major producmore stable carbocation; inductive effect of alkyl groups for the seco
C-O bond in IR is both broad for acids and alcohols
,Give a reason why carbon dioxide absorbs infrared radiatiC=O bonds vibrate at the same frequency as IR/ C=O
Intermolecular forces
Expain why a branched moleule has a lower boiling point than a non-branched moleuclHas weaker van der waa
Isomerism compounds with
stereoisomers Have the same structural and molecular formulae but a different arrangement of atoms in 3D spa
Chain isomerism different carbon chain ex methylpropene and but-1-ene
Position isomers different position of functional group ex: but-1-ene and but-2-ene;
Functional group isomers Have the same molecular formula but different functional groups ex aldehydes and
sterioisomerism info lack rotation around C=C; forms E Z isomers;
structural isomerism same molecular formula, different structural formula;
Polymers
Why is plasticiser added (1) more flexible
Explain why polyesters are biodegradable but polyalkenes are not biodepolyesters; polar bonds, polyalkenes ha
Can kevlar do hydrogen bonding?(1) yes
Suggest an environmental advantage of a condensation polymer compared to a addition polymer. Justify your a
Group 7
when chlorine gas is bubbled through sodium iodide what is the observatbrown solid (I2)
What is the colour of silver nitrate and NaF colourless; fluoride does not precipitate
State why the ozone layer is beneficial for living organismsabsorbs/prevents harmful UV
reactions of ozone order: initiation, propagation, termination
what is the purpose of adding nitric acid to form a precipitate of halides?HNO3 removes (hydroxide/carbonate) i
RANDOM pp q'ns
State in terms of electrons, the meaning of the term oxidising agent (1) electron acceptor
Explain how weak forces between chlorine molecules arrise (3) random mov of e- in one molecule, tem
standard enthalpy of combustion(2) enthalpy change when one mole of substance is completely combus
Hydrogen can be produced CH4 + H20 <-> CO + 3H2 .deltaH=+206. Temp 800 deg c, low pressure of 300kPa,
define relative atomic mass (mean mass of an atom of an element divided by 1/12 of the mass of C-12 isotope;;
define enthalpy change as applied to a chemical reaction change in heat energy at a constant pressure;
describe an enthalpy change experiment between CaCO3 (s) and HCl. Describe how an accurate temp change
Explain how ions are detected and relative abundance is measeure in a TOF mass spec (2)
What is potassium cyanide chemical formulCN:- K+
What is on the x axis and y axis of a maxwell boltzmann disx: energy; y: Number of moleNumber of moleucles
, Explain why propanone has a lower boiling point than propan-2-ol (3) Propan-2-ol has a stronger intermolecu
CFC-11 is a green house gas. Stage how this gas is able to contribute to global warming (2)
Thermal cracking and catalytic cracking difference Thermal: no catalyst, 800, alkanes and enes. Catalytic
Explain why poly(propene) is unreactive (1)Non-polar bonds;
explain why the minor product carbocation is less stabe(1)due to ele- raising character; or positive inductive effe
write 3 equations involving bioethanol and greenhouse gaphotosyntheses, combustion and fermentation.
Suggest two reasons why the value of enthalpy of combustion from this experiment is less exothermic than a da
what are concordant titers? within 0.1 cm^3 of eachother;
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