Definitions

Question 1

Atomic orbitals?

Answer 1

A region around the nucleus that can hold up to two electrons with opposite spin.

Question 2

What is the 1st ionisation energy?

Answer 2

Energy required to remove one mole of electrons from one mole of gaseous atoms producing ions of charge +1.

Question 3

What is ionic bonding?

Answer 3

Electrostatic attraction between positive and negatively charged ions.

Question 4

What is a covalent bond?

Answer 4

The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms.

Question 5

What is a dative covalent bond?

Answer 5

A covalent bond in which the shared pair of electrons has been provided by one of the bonding atoms only.

Question 6

What is electronegativity?

Answer 6

The ability of an atom to attract the bonding electrons in a covalent bond.

Question 7

What is a dipole?

Answer 7

The difference in charge between two atoms caused by a shift in electron density in the bond.

Question 8

What are intermolecular forces?

Answer 8

Forces between molecules.

Question 9

What is metallic bonding?

Answer 9

The strong electrostatic attraction between positive ions and negatively charged delocalised electrons in a regular lattice.

Question 10

What is a mole?

Answer 10

Amount of substance containing as many particles as there are carbon atoms in exactly 12g of C-12.

Question 11

What is Avogadro’s constant?

Answer 11

Number of particles per mole of a substance.

Question 12

What is empirical formula?

Answer 12

Simplest whole number ration of atoms to each element present in a compound.

Question 13

What is molecular formula?

Answer 13

Number and type of atoms of each element in a molecule.

Question 14

What is the titre?

Answer 14

The final reading off the burette taken from the initial reading.

Question 15

What is water of crystallisation?

Answer 15

Number of water molecules chemically combined in a definite molecular proportion, with the salt in its crystal state.

Question 16

What does hydrated mean?

Answer 16

A solid salt containing water of crystallisation.

Question 17

What does anhydrous mean?

Answer 17

A salt which doesn’t contain water of crystallisation.

Question 18

What is oxidation?

Answer 18

The loss of electrons and the increase in oxidation number.

Question 19

What is reduction?

Answer 19

The gain of electrons and a reduction in oxidation number.

Question 20

What are redox reactions?

Answer 20

When oxidation and reduction occur simultaneously in a reaction.

Question 21

What is enthalpy of combustion?

Answer 21

Enthalpy change for the complete combustion of 1 mole of a substance.

Question 22

What is enthalpy of formation?

Answer 22

When 1 mole of a substance is formed from its elements.

Question 23

What is a homologous series?

Answer 23

A series of organic compounds having the same functional group but with each successive member differing by CH2.

Question 24

What are structural isomers?

Answer 24

Compounds with the same molecular formula but different structural formula.

Question 25

What is a radical?

Answer 25

A species with an unpaired electron.

Question 26

What are stereoisomers?

Answer 26

Same structural formula but with a different arrangement in space.

Question 27

What is E/Z isomerism?

Answer 27

Example of stereoisomerism, in terms of restricted rotation about a double bond and the requirement for two different groups to be attached to each carbon atom of the C=C group.

Question 28

What is cis-trans isomerism?

Answer 28

A special case of E/Z isomerism in which two of the substituent groups are attached to each carbon atom of the C=C group are the same.

Question 29

What are electrophiles?

Answer 29

Electron pair acceptors.

Question 30

What are alkanes?

Answer 30

Saturated hydrocarbons containing single C-C and C-H bonds as sigma bonds.

Question 31

What are sigma bonds?

Answer 31

Overlap of orbitals directly between the bonding atoms.

Question 32

What are the standard conditions?

Answer 32

298K, 1atm, 1moldm-3

Question 33

What is average bond enthalpy?

Answer 33

Breaking 1 mole of bonds in gaseous molecules.

Question 34

What is a heterogenous catalyst?

Answer 34

One that is in a different phase from the other reactants.

Question 35

What is a homogenous catalyst?

Answer 35

One in the same phase as the reactants.

Question 36

What is a nucleophile?

Answer 36

An electron pair donor.

Question 37

What are CFCs?

Answer 37

Organic compounds that only contain chlorine, fluorine and carbon.

Question 38

What is the atomic number?

Answer 38

Number of protons in the nucleus.

Question 39

What is the mass number?

Answer 39

Total number of protons and neutrons in the nucleus.

Question 40

What is an isotope?

Answer 40

Atoms of an element with the same number of protons but different number of neutrons.

Question 41

What is the RAM?

Answer 41

Weighted mean mass compared with 1/12th mass of carbon-12.

Question 42

What is relative isotopic mass?

Answer 42

Mass of ab isotope compared with 1/12th mass of carbon-12.

Question 43

What are giant covalent lattices?

Answer 43

Huge networks of covalently bonded atoms.

Question 44

What are allotropes?

Answer 44

Different forms of the same element in the same state.

Question 45

What is a salt?

Answer 45

When the H+ in an acid is replaced by a metal ion / ammonium ion.

Question 46

What is enthalpy change of neutralisation?

Answer 46

Formation of 1 mole of water from neutralisation.