Formulae, amounts and equations terminology

Question 1

The mole

Answer 1

Unit for amount of a substance
Which is the amount of chemical species found in 12g of carbon-12

Question 2

Avogadro’s constant

Answer 2

The number of atoms in exactly 12g of carbon12
Which is 6.02 x 10⁻²³

Question 3

Molar mass

Answer 3

The mass per mole of a substance
Because different moles of a substance have different masses

Question 4

Relative molecular mass

Answer 4

Average mass of a molecule relative to 1/12th of the mass of an atom of carbon-12

Question 5

Empirical formular

Answer 5

Smallest whole number ratio of atoms of each element in a compound, e.g. the empirical formula of benzene (C6H6) is CH
Useful for giant lattices

Question 6

Molecular formular

Answer 6

The actual number of atoms of an element in a molecule

Question 7

Spectator ions

Answer 7

Ions in a reaction which do not take part

Question 8

Solution

Answer 8

Has a solute dissolved in a solvent

Question 9

Standard solution

Answer 9

The solution with an accurately known concentration

Question 10

Mass concentration

Answer 10

Mass of solute per volume of solution, gdm−3

Question 11

Molar concentration

Answer 11

Moles of solute per volume of solution, moldm−3

Question 12

Primary standard

Answer 12

A substance used for preparation of a standard solution by weighing