C3 0.0 / 5 ? ChemistryQuantitative ChemistryGCSEAQA Created by: Mr DaviesCreated on: 18-04-19 09:13 What is relative formula mass (Mr)? The sum of the relative atomic masses of all atoms show in the formula 1 of 16 State the Avogadro Constant and its purpose 6.02x10^23. It is the number of atoms/molecules/ions in one mole of a given substance 2 of 16 Give the formula linking moles, mass and Mr n = m / Mr 3 of 16 What is the law for conservation of mass? In a reaction, the total mass of the reactants must equal the total mass of the products 4 of 16 What is thermal decomposition? The break down of a substance into simpler substances using heat 5 of 16 When a metal reacts with oxygen, the mass of the product is greater than the mass of the original metal. Why? The "extra" mass is the mass of the oxygen from the air that has combined with the metal. 6 of 16 What is excess? When the amount of the reactant is greater than the amount that can react 7 of 16 What is the limilting reactant? The reactant that determines the amount of products formed - any other reactants are all in excess 8 of 16 State the formula for percentage yeild %Yeild = 100 x mass of product made / maximum theoretical mass 9 of 16 What is percentage yeild? Amount of product formed compared to the maximum theoretical mass that could be produced (as a %) 10 of 16 What is atom economy (atom utilisation)? Measuring what percentage of the mass of all the atoms in the reactants become the desired products 11 of 16 State the formula for Atom Economy %AE = 100 x sum of Mr of desired product / sum of Mr of all reactants (TIP: remember to take moles into account) 12 of 16 What is the formula for the volume of gases (in terms of moles)? V = 24n (providing it's at room temperature and pressure) 13 of 16 State the equation linking concentration, volume and mass concentration = mass / volume (here concentration is in g/dm^3) 14 of 16 State the equation linking concentration, volume and moles Concentration = moles / volume OR n = CV / 1000 (here concentration is in mol/dm^3) 15 of 16 Titration Calculations Method (for req practical see rev cards) 1: work out moles of solution of known conc (n = CV/1000). 2: work out molar ratio 3: calculate conc of other solution (n= CV/1000) 16 of 16
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