empirical and molecular formulae

Empirical formula is…

the simplest whole number ratio of the atoms of each element present in a compound

Empirical formula steps:

1. Calculate…, … and… for each element
2. Divide by…
3. Use mole ratio to form…

calculate mass, mr and moles, divide by smallest, use mole ratio to form formula

If answer for mole ratio is very close to whole number e.g 1.02 or 1.98,…

it can be rounded

If answer is 1.25, 1.33, 1.5, 1.66 or 1.75, then it and all other numbers need to be…

multiplied so answers are whole numbers

Molecular formula gives..

the number and type of atoms of each element in a molecule

Molecular formula steps:

1. Find…
2. Calculate… of empirical formula
3. Divide…by…
4. Multiply all.. by this value

find empirical formula, calculate mr of empirical formula, divide actual mr by empirical, multiply all numbers in formula