2026) EXAM QUESTIONS AND ALL CORRECT
ANSWERS 100% SOLVED AND GUARANTEED
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Relative atomic mass (AR) - CORRECT ANSWER-Average mass of an atom compared
with one twelfth of the mass of an atom of carbon 12
Electronegativity - CORRECT ANSWER-Power of an atom to attract the pair of
electrons in a covalent bond
Standard enthalpy of combustion - CORRECT ANSWER-Enthalpy change when 1 mole
of a substance burns completely in oxygen under standard conditions with all reactants
and products being in their standard state
Standard enthalpy of formation - CORRECT ANSWER-Enthalpy change when 1 mole
of a compound is formed from its elements under standard conditions in their standard
states
Mean bond enthalpy - CORRECT ANSWER-The average energy needed to break a
certain type of bond over a range of compounds
Activation energy - CORRECT ANSWER-Minimum energy required for colliding
molecules to react
Maxwell-Boltzmann distribution x and y axes - CORRECT ANSWER-x: Energy
y: fraction/number of molecules
What happens to the Maxwell-Boltzmann curve when temperature increases -
CORRECT ANSWER-Moves down and to the right
Rate of reaction - CORRECT ANSWER-Rate at which product formed/reactant used up
Order of reaction - CORRECT ANSWER-Power to which the concentration of a species
is raised in the rate equation
rearrange k=Ae^-Ea./Rat - CORRECT ANSWER-link=-Ea./Rt+lnA
, Conditions for thermal cracking - CORRECT ANSWER-High temperature and high
pressure
Products of thermal cracking - CORRECT ANSWER-High % of alkenes
Conditions for catalytic cracking - CORRECT ANSWER-High temperature, slight
pressure and in the presence of a zeolite catalyst
Products of catalytic cracking - CORRECT ANSWER-Motor fuels and aromatic
hydrocarbons
Why do we crack alkanes? - CORRECT ANSWER-Smaller alkanes/alkenes generally
more useful than longer chain ones
Equation for complete combustion of alkanes - CORRECT ANSWER-alkane + oxygen >
carbon dioxide + water
Equations for incomplete combustion of alkanes - CORRECT ANSWER-alkane +
oxygen > carbon monoxide/carbon + water
Pollutants produced by combustion engines - CORRECT ANSWER-NOx, CO, C and
sunburned hydrocarbons
Reaction of methane with chlorine - CORRECT ANSWER-I: Cl2 > 2Cl•
P: CH4 + Cl• > CH3• + Chi
CH3• + Cl2 > CH3Cl + Cl•
T: CH3• + Cl• > CH3Cl
2 equations showing decomposition of the ozone - CORRECT ANSWER-Cl• + O3 >
Clod• + O2
Clod• + O3 > 2O2 + Cl•
What types of mechanism do halo alkanes undergo? - CORRECT ANSWER--
Nucleophilic substitution by aqueous hydroxide ions, cyanide ions or ammonia
-Elimination with ethanoic hydroxide ions
What type of mechanism do alkenes undergo? - CORRECT ANSWER-Electrophilic
addition by bromine, hydrogen bromide or sulphuric acid