- Each molecule is made of up two hydrogen atoms and one sulfur atom. The ratio is 2:1
- A formula unit is the smallest unit in an ionic compound. The composition of a formula unit is the same as the composition of the ionic compound.
- 12C: A mole is the amount of substance that contains as many basic particles (atoms, molecules, or formula units) as there are atoms in excatly 12g of 12C
- Molar Mass is the mass of 1 mol of substance
- The molar mass of a molecular or ionic substance has the same value as the sum of the relative atomic mass of its cmpound elements.
- Molar mass of molecules (or formula units) are obtained by adding the molar mass of the component elements, each weighted by the number of that atom in the molecule
- The Molar Mass of a compound is the sum of the molar mass of its elements