1

Question 1

Chemical symbol

Answer 1

A representation of an element using letters.

Question 2

Chemical formula

Answer 2

A representation of the composition of a substance using chemical symbols and numeric subscripts.

Question 3

Subscript

Answer 3

A whole number that appears to the right and below a chemical symbol in a chemical formula (if no number is written it is assumed to be ‘1’).

Question 4

coefficient

Answer 4

A whole number that appears in front of a reactant or product in a balanced chemical equation (if no number is written it is assumed to be ‘1’).

Question 5

atom

Answer 5

The smallest particle of an element that retains the chemical properties of that element.

Question 6

ion

Answer 6

An atom or group of atoms with a positive or negative charge.

Question 7

anion

Answer 7

A negative ion.

Question 8

cation

Answer 8

A positive ion.

Question 9

monatomic ion

Answer 9

An ion formed from a single atom.

Question 10

polyatomic ion

Answer 10

A group of bonded atoms with a charge.

Question 11

formula unit

Answer 11

The smallest electrically neutral collection of positive and negative ions (anions and cations) in an ionic compound.

Question 12

ionic formula

Answer 12

A chemical formula showing the types and numbers of ions in a formula unit.

Question 13

molecule

Answer 13

A neutral group of atoms held together by covalent bonds, which acts as an independent unit capable of existing on its own.

Question 14

molecular formula

Answer 14

A chemical formula showing the types and numbers of atoms combined in a single molecule.

Question 15

acid

Answer 15

A distinctive class of chemical compounds which you will learn much more about in later units.

Question 16

binary acid

Answer 16

An acid composed of hydrogen and a second element.

Question 17

oxyacid

Answer 17

An acid composed of hydrogen, oxygen, and a third element.

Question 18

mole

Answer 18

A counting unit that measures ‘how many’.

Question 19

Avogadro’s number

Answer 19

The number of particles in one mole of a pure substance; 6.022136736 × 10^23; we will use 6.022 x 10^23.

Question 20

atomic mass unit (amu)

Answer 20

1/12 mass of a carbon-12 atom.

Question 21

atomic mass

Answer 21

The mass of one atom expressed in atomic mass units (amu).

Question 22

formula mass

Answer 22

The mass of one molecule or formula unit expressed in atomic mass units (amu).

Question 23

molar mass

Answer 23

The mass of one mole of atoms, molecules, or formula units expressed in grams or grams per mol.

Question 24

percent composition

Answer 24

The percentage by mass of each element in a compound.

Question 25

law of constant composition

Answer 25

A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

Question 26

empirical formula

Answer 26

A chemical formula showing the simplest whole number ratio of atoms in a compound.

Question 27

hydrate

Answer 27

An ionic compound containing water molecules incorporated into its solid crystal structure.

Question 28

anhydrous salt

Answer 28

The ionic compound that remains after the water has been removed from a hydrate (usually by heating).

Question 29

salt

Answer 29

An ionic compound (usually an ionic compound that does not contain OH- ions).