Definitions

Question 1

Define diffusion

Answer 1

Process that takes place when a gas/liquid moves from a region of high concentration to a region of lower concentration.

Question 2

Define melting Point

Answer 2

A fixed temperature at which a solid completely changes state to a liquid.

Question 3

Define freezing point

Answer 3

A fixed temperature at which a liquid completely changes state to a solid.

Question 4

Define boiling point

Answer 4

A fixed temperature at which a liquid completely changes state to a gas.

Question 5

Define condensation point

Answer 5

A fixed temperature at which a gas completely changes state to a liquid.

Question 6

Define sublimation

Answer 6

a fixed temperature at which a solid completely changes state to a gas.

Question 7

Define deposition

Answer 7

A fixed temperature at which a gas completely changes state to a solid.

Question 8

Define temperature

Answer 8

A measure of a substance’s internal energy.

Question 9

Define heat

Answer 9

Is the energy in transit due to a difference in temperature and always flows from hot to cold. (Heat is not to be confused with warmth-being warm)

Question 10

Define atom

Answer 10

An atom is the smallest building block of matter.

Question 11

Define atomic mass unit (a.m.u)

Answer 11

One-twelfth of the mass of a carbon-12 atom.

Question 12

Define isotope

Answer 12

An atom with the same number of protons but a different number of neutrons in its nucleus.

Question 13

Define relative atomic mass

Answer 13

The mass of the element compared with the mass of a carbon-12 atom.

Question 14

Define electron configuration

Answer 14

The arrangement of electrons in an atom.

Question 15

Define Pauli’s Exclusion Priniciple

Answer 15

Electrons of opposite spin occupy the same orbital.

Question 16

Define Hund’s Rule

Answer 16

electrons enter orbitals singly before pairing up.

Question 17

Define valence electrons

Answer 17

The electrons in the outermost energy level of the atom that will determine how an atom will react in a chemical reaction.

Question 18

Define core electrons

Answer 18

The remaining electrons that make up the atom

Question 19

Define periodic law

Answer 19

States that the elements are arranged in increasing atomic number and shows periodic change in their properties.

Question 20

Define valence electrons

Answer 20

The electrons in the outermost energy level of the atom that will determine how an atom will react in a chemical reaction.

Question 21

Define ion

Answer 21

Any charged particle.(Charge is created when a neutral atom gains or loses electrons.)

Question 22

Define octet rule

Answer 22

Atoms gain, lose or share electrons to achieve the stable electronic configuration of the noble gases.

Question 23

Define Electron Affinity

Answer 23

The amount of energy released per mole when an elements’ atoms gain an electron.

Question 24

Define electronegativity

Answer 24

A measure of the tendency of an atom to attract a bonding pair of electrons towards itself.

Question 25

Define allotropes

Answer 25

Each of two or more different physical forms in which an element can exist.

Question 26

Define intermolecular forces

Answer 26

A weak force of attraction between molecules, ions, or atoms of noble gases.

Question 27

Define intramolecular forces

Answer 27

A bond which occurs between atoms within molecules.

Question 28

Define viscosity

Answer 28

A measure of the ability of a liquid to flow.(A liquid with high viscosity does not flow very easily).

Question 29

Define electrolysis

Answer 29

Chemical decomposition of a substance by passing an electric current through a liquid or solution containing ions.

Question 30

Define catalyst

Answer 30

A substance which speeds up the rate of a chemical reaction without its chemical composition being changed by the reaction. (In a chemical equation the catalyst is written on top of the arrow.)

Question 31

Define synthesis reaction

Answer 31

A chemical reaction where the product that is formed is more complex than each of the reactants.

Question 32

Define decomposition reaction

Answer 32

A chemical reaction where the product breaks down to form simpler substances.

Question 33

Define exothermic reaction

Answer 33

Reactions which transform chemical potential energy into thermal energy.( Release heat and thus increase the temperature of the reaction mixture)

Question 34

Define endothermic reaction

Answer 34

Reactions which transform thermal energy into chemical potential energy. (Absorb heat and thus decrease the temperature of the reaction mixture)

Question 35

Define the law of conservation of energy

Answer 35

In an isolated system energy cannot be created nor destroyed, it can only be transferred from one place to another.

Question 36

Define the law of constant proportions

Answer 36

Some elements in a chemical compound that bond in a fixed ratio with one another.

Question 37

Define reactants

Answer 37

Substance that combine during a chemical reaction to form the product.(Left-hand side of arrow)

Question 38

Define products

Answer 38

Substances that form during a chemical reaction when the reactants react with each other.(Right-hand side of arrow)