Mr, Ar and moles

• Mr is the relative formula mass
• the relative formula mass of a compound is the sum of the relative atomic masses of the atoms in the number shown in the formula
• one mole of any substance contains 6.02 x 10^23 particles
• moles = number of particles divided by 6.02 x 10^23
• number of particles = moles x (6.02 x 10^23)
• moles = mass divided by Ar or Mr