Topic 2: Quantitative Analysis

Topic 2: Quantitative Analysis

1. An equation of a reaction will tell you: how many particles of reactants and products there are, how many moles there are & how many grams there are

   • C + O2 = CO2 ...... 1 atom of carbon, 1 mol of atoms and 12 grams

2. A mole is a measure of the amount of substance. A mole of any element always has the same amount of particles as any other element (6.0225 x 10'23)

   • The mass of a mole of any element is the same as the RAM of that element e.g. carbon's RAM = 12, 12 g of carbon in 1 mole

3. Relative formula mass (RFM) = the RAM's of all a compounds component elements added together e.g. CO2 = 12 + (16x2) = 44

4. Mass(g) = RAM or RFM x no. of moles

5. Concentration is a measure of the amount of solute in 1 cubic decimetre of solution. (gdm'3)

   • 1dm'3 = 1000cm'3
   • Conc (gdm'3) = mass (g) / volume of solution (dm'3)

6. Concentration can also be measured in moles per cubic decimetre (mol dm'3)

   • amount (mol) = concentration (mol dm'3) x volume (dm'3)

7. The mass of solute can be measured by evaporating all the water and measuring the mass of the solid left behind

   • mass of solute = (mass of container + solute) - mass of container
   • Mass of solvent = (mass of container + solution) - (mass of container + solute)

8. Neutrilisation with titration : hydrogen ions from acid combine with hydroxide ions from alkali to make water.(neutral) H + OH = H20

   • acid + base = salt + water

9. Salts from insoluble bases: a commonly used insoluble base is copper oxide which produces the salt copper sulfate when mixed with sulfuric acid

   • Excess copper oxide is added to a measure volume of sulfuric acid until there is evidence of copper oxide left behind.
     • It is then filtered to remove the CuO which leaves a solution of copper sulfate.
       • The water can then be evaporated off after it has been washed with distilled water to remove impurities