Empirical and molecular formula

Question 1

What is the empirical formula?

Answer 1

A formula that represents the simple whole number ratio of the atoms of each element present in a compound

Question 2

What is the empirical formula for carbon dioxide and what does it show?

Answer 2

The empirical formula for carbon dioxide is CO2 and it shows that for every carbon atom there are two oxygen atoms

Question 3

How do you find the empirical formula?

Answer 3

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

Question 4

Question: A compound contains 23.3% magnesium, 30.7% sulfur and 46% oxygen. What is the empirical formula?

Answer 4

Empirical formula: MgSO3

Question 5

What is the molecular formula?

Answer 5

The molecular formula gives the actual number of atoms of each element in molecule of a compound

Question 6

Is the molecular formula always the same as the empirical formula?

Answer 6

No, the empirical formula can be different from the molecular formula

Question 7

How do you calculate molecular formula?

Answer 7

Relative molecular mass of substance divided by relative mass of empirical formula of substance