Importants -

1. OH- = hydroxide
2. NH4 + = Ammonium
3. NO3 1- = nitrate
4. SO4 2- = sulfate
5. CO3 2- = carbonate
6. PO4 3- = phosphate

Avogadros Constant - 6.02 x 10^23 == Number of molecules in a single mole - number of particles in 12 grams of carbon 12

24 dm^3 in 1 mole of gas

cm^3 → dm^3 = Divide by 1000

dm^3 → cm^3 = Multiply by 1000

Eg Question -

1. How many molecules are there in 2 moles of O2
   1. 2 x Avogadros
2. How many atoms are there in 2 moles of O2
   1. 2 x 2 x Avogadros
3. How many atoms are there in 50 grams of C
   1. Mol = 50/12 = 4.16
   2. 4.16 x Avogadros
4. How many molecules in 48 dm^3 of O2
   1. 1 mol = 24 dm^3, hence this is 2 moles
   2. 2 x Avogadros