Topic 3: Stoichemistry

Question 1

Molecular formula

Answer 1

of a compound is the number and type of different atoms in one molecule

Question 2

Empirical formula

Answer 2

of a compound is the simplest whole number ratio of the different atoms or ions in a compound

Question 3

Relative atomic mass, Ar

Answer 3

is the average mass of the isotopes of an element
compared to 1/12th of the mass of an atom of 12C

Question 4

Relative molecular mass, Mr

Answer 4

is the sum of the relative atomic masses

Question 5

Relative formula mass, Mr

Answer 5

is used for ionic compounds

Question 6

A mole

Answer 6

is the unit of amount of substance and 1 mole contains 6.02 x 10^23 atoms, ions or molecules

Question 7

Avogadro’s Constant

Answer 7

6.02 x 10^23

Question 8

Displayed formula

Answer 8

shows all the atoms and bonds in a molecule.