AS-level AQA Chemistry Exam Study Questions
with Complete Solutions Latest Update
2024
Polarity - ANSWER The unequal sharing of the electrons between atoms in a covalent bond
Polar - ANSWER Describes a molecule where the charge is not equally distributed, one end
is more positive, the other more negative
Dipole-dipole forces - ANSWER An intermolecular force between two molecules
with permanent dipoles
van der Waals forces - ANSWER An intermolecular force between all atoms and molecules
caused by instantaneous dipoles which form very weak electrostatic attractions
Hydrogen bonding - ANSWER An intermolecular force between a slightly positive hydrogen
atom and a much more electronegative atom which forms a strong interaction
Electron pair repulsion theory - ANSWER Suggests that the electrons surrounding the central
atom in the atoms repel each other, therefore the atoms form a shape where they are
furthest away from each other
Linear - ANSWER 2 pairs of electrons shape
180 - ANSWER 2 pairs of electrons bond angle
Trigonal planar - ANSWER 3 pairs of electrons shape
120 - ANSWER 3 pairs of electrons bond angle
,Tetrahedral - ANSWER 4 pairs of electrons shape
109.5 - ANSWER 4 pairs of electrons bond angle
Trigonal bipyramid - ANSWER 5 pairs of electrons shape
120 - ANSWER 5 pairs of electrons bond angle
Octahedral - ANSWER 6 pairs of electrons shape
90 - ANSWER 6 pairs of electrons bond angle
-2 - ANSWER Effect of one lone pair on bond angle
Enthalpy change - ANSWER The heat energy change measured under constant pressure whilst
temperature depends on the average kinetic energy of the particles
Enthalpy change of vaporisation - ANSWER The energy required to turn a substance from
a liquid to a gas
Electrical current - ANSWER Usually carried by delocalised electrons or ions
Simple molecular structure - ANSWER Composed of small molecules held together by covalent
bonds
Macromolecular structure - ANSWER Large numbers of atoms are linked in a regular 3D shape
by covalent bonds
, Giant ionic structure - ANSWER Consists of a lattice of positive ions each surrounded
by negative ions and vive versa
Metallic structure - ANSWER Consists of a regular lattice of positively charged metal ions held
together by a cloud of delocalised electrons
Low boiling points - ANSWER Simple molecular compounds melting and boiling points
High boiling points - ANSWER Giant structures general melting and boiling points
Energy to break bonds - ANSWER Energy put in
Energy to make bonds - ANSWER Energy given out
Exothermic reaction - ANSWER Heat energy given out as the reactants change to the products
Endothermic reaction - ANSWER Heat energy taken in as the reactants change to the products
Standard conditions - ANSWER Pressure= 100kPa
Temperature= 298K
Standard molar enthalpy of formation - ANSWER The enthalpy change when one mole of
substance is formed from its constituent elements under standard conditions, all reactants
and products being in their standard states
Standard molar enthalpy of combustion - ANSWER The enthalpy change when one mole of
substance is completely burnt in oxygen under standard conditions, all reactants and
products being in their standard states
with Complete Solutions Latest Update
2024
Polarity - ANSWER The unequal sharing of the electrons between atoms in a covalent bond
Polar - ANSWER Describes a molecule where the charge is not equally distributed, one end
is more positive, the other more negative
Dipole-dipole forces - ANSWER An intermolecular force between two molecules
with permanent dipoles
van der Waals forces - ANSWER An intermolecular force between all atoms and molecules
caused by instantaneous dipoles which form very weak electrostatic attractions
Hydrogen bonding - ANSWER An intermolecular force between a slightly positive hydrogen
atom and a much more electronegative atom which forms a strong interaction
Electron pair repulsion theory - ANSWER Suggests that the electrons surrounding the central
atom in the atoms repel each other, therefore the atoms form a shape where they are
furthest away from each other
Linear - ANSWER 2 pairs of electrons shape
180 - ANSWER 2 pairs of electrons bond angle
Trigonal planar - ANSWER 3 pairs of electrons shape
120 - ANSWER 3 pairs of electrons bond angle
,Tetrahedral - ANSWER 4 pairs of electrons shape
109.5 - ANSWER 4 pairs of electrons bond angle
Trigonal bipyramid - ANSWER 5 pairs of electrons shape
120 - ANSWER 5 pairs of electrons bond angle
Octahedral - ANSWER 6 pairs of electrons shape
90 - ANSWER 6 pairs of electrons bond angle
-2 - ANSWER Effect of one lone pair on bond angle
Enthalpy change - ANSWER The heat energy change measured under constant pressure whilst
temperature depends on the average kinetic energy of the particles
Enthalpy change of vaporisation - ANSWER The energy required to turn a substance from
a liquid to a gas
Electrical current - ANSWER Usually carried by delocalised electrons or ions
Simple molecular structure - ANSWER Composed of small molecules held together by covalent
bonds
Macromolecular structure - ANSWER Large numbers of atoms are linked in a regular 3D shape
by covalent bonds
, Giant ionic structure - ANSWER Consists of a lattice of positive ions each surrounded
by negative ions and vive versa
Metallic structure - ANSWER Consists of a regular lattice of positively charged metal ions held
together by a cloud of delocalised electrons
Low boiling points - ANSWER Simple molecular compounds melting and boiling points
High boiling points - ANSWER Giant structures general melting and boiling points
Energy to break bonds - ANSWER Energy put in
Energy to make bonds - ANSWER Energy given out
Exothermic reaction - ANSWER Heat energy given out as the reactants change to the products
Endothermic reaction - ANSWER Heat energy taken in as the reactants change to the products
Standard conditions - ANSWER Pressure= 100kPa
Temperature= 298K
Standard molar enthalpy of formation - ANSWER The enthalpy change when one mole of
substance is formed from its constituent elements under standard conditions, all reactants
and products being in their standard states
Standard molar enthalpy of combustion - ANSWER The enthalpy change when one mole of
substance is completely burnt in oxygen under standard conditions, all reactants and
products being in their standard states
