Empirical and molecular formula

Question 1

What is the empirical formula?

Answer 1

It is the simplest formula for a compound/ simplest whole number ratio of atoms in a molecule.

Question 2

What is the equation that links mass of an element, moles and mass of 1 mole of an element?

Answer 2

Mass of element= number of moles x mass of 1 mole of element

Question 3

What are the steps to find the empirical formula?

Answer 3

1. Find the masses of each of the elements present in a compound (the Mr)
2. Work out the number of moles of atoms in each element
3. Convert the number of moles of each element into a whole number ratio.

Question 4

How do you find the simplest ratio of an element?

Answer 4

1. Find the number of moles of atoms of each element.
2. Find the simplest ratio through dividing the moles by the smallest mole out of them, acting as a denominator.

Question 5

What are the units for moles, mass and mr, aka molar mass?

Answer 5

Mass = g
Moles = mol
Mr = g/ mol

Question 6

What is the molecular formula?

Answer 6

It is the actual number of atoms in each element of a molecule.

Question 7

True or false; the molecular formula is always a multiple of the empirical formula.

Answer 7

True

Question 8

What is the equation for molecular formula?

Answer 8

Relative molecular mass (Mr) / Relative mass of empirical formula