C3-Quantitative chemistry

• finding the Mr MgCL2. Mg is 24 CL is 35.5 so the Mr is 95
• percentage mass of an element in a compound = (Ar x number of atoms of that element) / Mr of the compound x100
• a mole value is 6.02x10^23
• one mole is equivalent to relative formula mass in grams
• number of moles = mass in g ( of an element or compound ) / Mr (of an element or compound )
• in a chemical reaction mass is always conserved no atoms are destroyed or loss
• reactions stop once one reactant is used up
• the amount of product depends on the limiting reactant
• concentration = mass of solute / volume of solvent
• concentration is measured of how crowded things are