C3: Quantitative Chemistry

• Conservation if mass means that the total mass of the reactants is equal to the total mass of the products
• Relative Formula Mass is the sum of the relative masses of each atom in a compound
• The four state symbols are: solid (s), liquid (l), gas (g), aqueous (aq)
• The symbol used for relative formula mass is Mr
• The units for concentration are: g/dm3 and mol/dm3
• Concentration = Moles / Volume
• The law of Conservation of Mass states that no atoms can be gained or lost in a chemical reaction
• In reactions involving gases, there is a possible change of mass, as the gas could have escaped the reaction area
• A balanced equation shows how many moles of each substance take part in a reaction
• The uncertainty is the mean + or - (1/2 x range).
• The bigger the range around the mean, the more uncertainty there is about the results
• Mass = Mr x Moles
• The limiting reactant is the reactant that is all used up in the equation, and sets a limit on the amount of product produced
• If we know the number of moles of one reactant, we can calculate the number of moles of another using the mole ratio from the balanced equation.
• Concentration = Mass / Volume
• Volume = 24 x Moles
• % Yield = (actual mass of product / theoretical mass of product) x 100
• The theoretical mass is how much of it you expect to get in a reaction
• % Atom Economy = (Atoms of useful product) / (Atoms of all products) x 100
• A solution is formed when a solute is dissolved in a solvent.