Unit 1 - Chemical Changes & Structures

Question 1

A very unstable arrangement of atoms formed at the maximum of the potential energy barrier, during a chemical reaction.

Answer 1

Activated Complex

Question 2

The minimum kinetic energy required by colliding particles before a reaction will occur, since high energy activated complex must be formed.

Answer 2

Activation energy

Question 3

Substance which increases the rate of reaction without being used up, often a transmission metal.

Answer 3

Catalyst

Question 4

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

Answer 4

Chemical Bonding

Question 5

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

Answer 5

Chemical structure

Question 6

Of reactions suggests that, for a chemical reaction to occur, particles must collide.

Answer 6

Collision theory

Question 7

Formed when two atoms share electrons in their outer shell to complete the filing of that shell

Answer 7

Covalent bond

Question 8

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

Answer 8

Covalent radius

Question 9

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

Answer 9

Delocalised electrons.

Question 10

Molecules with only two atoms (e.g. oxygen, O2, and carbon dioxide, CO)

Answer 10

Diatomic molecules

Question 11

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

Answer 11

Dipole

Question 12

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

Answer 12

Electronegativity

Question 13

The energy required to remove one mole of electrons from one mole of atoms in the gaseous state.

Answer 13

First ionisation energy

Question 14

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

Answer 14

Fullerene

Question 15

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

Answer 15

Hydrogen Bonding

Question 16

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

Answer 16

Intermolecular forces

Question 17

Forces of attraction which exist within a molecule.

Answer 17

Intramolecular forces

Question 18

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.

Answer 18

Lattice

Question 19

The forces of attraction which result from the electrostatic attraction between temporary dipoles and induced dipoles caused by movement of electrons in atoms and molecules.

Answer 19

London Dispersion Forces

Question 20

Fluids which mix with or dissolve in each other in all proportions

Answer 20

Miscible

Question 21

The regular recurrence of similar properties when the elements are arranged in order of increasing atomic number.

Answer 21

Periodicity

Question 22

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

Answer 22

Polar bond

Question 23

Shows the enthalpy of reactants and products and the enthalpy change during a chemical reaction

Answer 23

Thermal chemical equation

Question 24

Of a substance are their physical and chemical characteristics. These are often a reflection of the chemical Bonding and structure of the material.

Answer 24

Properties

Question 25

The resistance to flow that is exhibited by all liquids.

Answer 25

Viscosity