OCS A Level Chemistry A 2023 Exam Synthesis and
Analytical Techniques Version 2 Top Prediction 100%
Relative atomic mass - ANSWER: The weighted mean mass of an atom of an element
compared with one-twelfth of the mass of an atom of carbon-12.
Relative isotopic mass - ANSWER: The mass of an atom of an isotope compared with
one-twelfth of the mass of an atom of carbon-12.
empirical formula - ANSWER: The simplest whole number ratio of atoms of each
element present in a compound
molecular formula - ANSWER: A chemical formula that shows the number and kinds
of atoms in a molecule, but not the arrangement of the atoms.
anhydrous - ANSWER: without water
Hydrated - ANSWER: A crystalline compound containing water molecules
Water of crystallisation - ANSWER: Water molecules that are bonded into a
crystalline structure of a compound
strong acid - ANSWER: an acid that ionises/dissociates completely in aqueous
solution
Weak acid - ANSWER: an acid that is only slightly ionised/dissociated in aqueous
solution
Oxidation - ANSWER: loss of electrons
Reduction - ANSWER: gain of electrons
Ionic bonding - ANSWER: The electrostatic attraction between oppositely charged
ions
Covalent bonds - ANSWER: sharing of a pair of electrons
Electronegativity - ANSWER: the ability of an atom to attract the electrons in a
covalent bond
1st ionisation energy - ANSWER: energy change when one mole of electrons is
removed from one mole of gaseous atoms
Metallic bonding - ANSWER: the chemical bonding that results from the attraction
between metal ions and the surrounding delocalised electrons
Analytical Techniques Version 2 Top Prediction 100%
Relative atomic mass - ANSWER: The weighted mean mass of an atom of an element
compared with one-twelfth of the mass of an atom of carbon-12.
Relative isotopic mass - ANSWER: The mass of an atom of an isotope compared with
one-twelfth of the mass of an atom of carbon-12.
empirical formula - ANSWER: The simplest whole number ratio of atoms of each
element present in a compound
molecular formula - ANSWER: A chemical formula that shows the number and kinds
of atoms in a molecule, but not the arrangement of the atoms.
anhydrous - ANSWER: without water
Hydrated - ANSWER: A crystalline compound containing water molecules
Water of crystallisation - ANSWER: Water molecules that are bonded into a
crystalline structure of a compound
strong acid - ANSWER: an acid that ionises/dissociates completely in aqueous
solution
Weak acid - ANSWER: an acid that is only slightly ionised/dissociated in aqueous
solution
Oxidation - ANSWER: loss of electrons
Reduction - ANSWER: gain of electrons
Ionic bonding - ANSWER: The electrostatic attraction between oppositely charged
ions
Covalent bonds - ANSWER: sharing of a pair of electrons
Electronegativity - ANSWER: the ability of an atom to attract the electrons in a
covalent bond
1st ionisation energy - ANSWER: energy change when one mole of electrons is
removed from one mole of gaseous atoms
Metallic bonding - ANSWER: the chemical bonding that results from the attraction
between metal ions and the surrounding delocalised electrons
