Calculating moles of an element.

https://www.youtube.com/watch?v=-_-fNVmDwJk&list=PL9IouNCPbCxUhxxFUbR4SNfwmaRB8mYX3&index=7&ab_channel=Freesciencelessons

What number do we use for relative atomic mass. (Ar)

The top number of a element in periodic table.

How do we work out number of moles.

Number of moles = Mass (g) / Relative atomic mass (Ar)

Explain moles.

Carbon has Ar of 12, meaning 12g of carbon is 1 mole of carbon atoms.

Same for oxygen it has Ar of 16, meaning 16g of oxygen is one mole of oxygen atoms.

You are given a sample of magnesium with mass of 48g. How many moles of Mg have u been given

48 g / 24, which is 2 moles of magnesium