Unit 1: Rate of Reactions Glossary

Question 1

What is the definition of Activation Energy?

Answer 1

The minimum amount of energy needed for a reaction to begin.

Question 2

What is the definition of a catalyst?

Answer 2

A chemical which speeds up a chemical reaction without being used up itself and which can be removed chemically unchanged at the end of the reaction and can be used again.

Question 3

What is the definition of a catalytic converter?

Answer 3

A catalyst found in an exhaust pf cars. It changes harmful gases into less harmful gasses. It is usually made of platinum.

Question 4

What is the definition of a chemical reaction?

Answer 4

An interaction between substances (chemicals) in which their atoms re-arrange to form new substances.

Question 5

What is the definition of concentration?

Answer 5

The amount of particles in a given volume.

Question 6

What is the definition of an enzyme?

Answer 6

A biological catalyst (i.e. a catalyst found in living things).

Question 7

What is the definition of a fair test?

Answer 7

When only one experimental variable is altered at a time.

Question 8

What is the definition of products?

Answer 8

The substances (chemicals) at the end of a chemical reaction.

Question 9

What is the definition of rate of reaction?

Answer 9

How quickly a reactant is used up or how quickly a product is created.

Question 10

What is the definition of reactants?

Answer 10

The substances (chemicals) at the start of a chemical reaction.

Question 11

What is the definition of surface area?

Answer 11

Total area of a substance which is exposed to the surroundings.

Question 12

What is the definition of a variable?

Answer 12

Something which can be changed in a chemical reaction.

Question 13

What is the definition of Covalent radius?

Answer 13

half the distance between the nuclei of two bonded atoms of an element.

Question 14

What is the definition of density?

Answer 14

The density of a substance is its mass per unit volume, usually in g/cm3.

Question 15

What is the definition of electronegativity?

Answer 15

A measure of the attraction the nucleus of an atom involved in a bond has for the electrons of the bond.

Question 16

What is the definition of the ionisation energy?

Answer 16

The first ionisation energy is the amount of energy required to remove one mole of electrons from one mole of atoms in the GASEOUS state.The second and subsequent ionisation energy refers to the energy required to remove a further mole of electrons from one mole of atoms in the gaseous state.

Question 17

What is the definition of periodicity?

Answer 17

The occurrence of patterns in the periodic table.

Question 18

What is the definition of the screening effect?

Answer 18

When inner electrons shield on outer electron from the attractive effect of the nucleus and less energy is needed to remove the outer electron as a result.

Question 19

What is the definition of bonding electrons?

Answer 19

The shared pair of electrons from both atoms forming the covalent bond.

Question 20

What is the definition of chemical bonding?

Answer 20

The term used to describe the mechanism by which atoms are held together.

Question 21

What is the definition of chemical structure?

Answer 21

Describes the way in which atoms, ions or molecules are arranged.

Question 22

What is the definition of the covalent bond?

Answer 22

A covalent bond is formed when two atoms share electrons in their outer shell to complete the filling of that shell.

Question 23

What is the definition of delocalised?

Answer 23

Delocalised electrons, in metallic bonding, are free from attachment to any one metal ion and are shared amongst the entire structure.

Question 24

What is the definition of D dipole

Answer 24

An atom or molecule in which a concentration of positive charges is separated from a concentration of negative charges.

Question 25

What is the definition of the fullerenes?

Answer 25

Molecules of pure carbon constructed from 5 and 6-membered rings combined into hollow structures. The most stable contains 60 carbon atoms in a shape resembling a ball.

Question 26

What is the definition of Hydrogen bonds?

Answer 26

The electrostatic forces of attraction between molecules containing a hydrogen atom bonded to an atom of a strongly electrongative element such as fluorine, oxygen or nitrogen and a highly electronegative atom on a neighbouring molecule.

Question 27

What is the definition of intermolecular forces?

Answer 27

Forces which attract molecules together. They are weaker than chemical bonds.

Question 28

What is the definition of Intramolecular forces?

Answer 28

Forces of attraction which exist within a molecule.

Question 29

What is the definition of isoelectronic?

Answer 29

Isoelectronic means having the same arrangement of electrons. For example, the noble gases, a sodium ion (Na+) and magnesium ion (Mg2+) are isoelectronic.

Question 30

What is the definition of lattice?

Answer 30

A lattice is a regular 3D arrangement of particles in space. the term is applied to metal ions in a solid, and to positive and negative ions in an ionic solid.

Question 31

What is the definition of London Dispersion forces?

Answer 31

London Dispersion Forces are the intermolecular forces of attraction which result from the electrostatic attraction between temporary dipoles and induced dipoles caused by the movement of electrons in atoms and molecules.

Question 32

What is the definition of Lone pairs?

Answer 32

Lone pairs are pairs of electrons in the outer shell of an atom which take no part in bonding.

Question 33

What is the definition of miscible?

Answer 33

Miscible fluids are fluids which mix with or dissolve in each other in all proportions.

Question 34

What is the definition of polar covalent bonding?

Answer 34

A covalent bond between atoms of different electronegativity, which results in an uneven distribution of electrons and a partial charge along the bond.

Question 35

What is the definition of Van der Waal’s forces?

Answer 35

Is the general name given to all the intermolecular attraction including London dispersion forces, Permanent dipole to permanent dipole interactions and hydrogen bonding.

Question 36

What is the definition of viscosity?

Answer 36

Viscosity id the resistance to flow that is exhibited by all liquids.