1. Volumetric analysis

2. Mole concept map For the reaction A + B  C, where A is the limiting reagent, concentration particles mass volume (gas) MOLE (A) MOLE (A) MOLE (C) MOLE (C) concentration particles mass volume (gas) Mole ratio

3. concentration particles mass volume (gas) MOLE (A) MOLE (A) MOLE (C) MOLE (C) concentration particles mass volume (gas) Mole ratio Number of moles = mass / Molar mass Number of moles = volume of gas / 24 dm 3 Number of moles = number of particles / 6.02 x 10 23 Number of moles = concentration x volume

4. What is a standard solution? A standard solution is a solution of accurately known concentration A known mass of solute is dissolved in a solvent and made up to a known volume of solution in a volumetric flask

5. Standard solutions Eg: 10 g of NaOH was dissolved in water and made up to 1 dm 3. What is the concentration of NaOH? 23 Na, 16 O, 1 H Mr(NaOH) = 23 + 16 + 1 = 40 n(NaOH) = mass/Mr = 10/40 = 0.250 mol Concentration = number of mol / volume = 0.250 / 1 = 0.250 mol/dm 3

6. Titration (acid-base) How can we use the standard solution of NaOH to determine the concentration of a solution of HCl of unknown concentration? NaOH + HCl  NaCl + H 2 O concentration particles mass volume (gas) MOLE (NaOH) MOLE (NaOH) MOLE (HCl) MOLE (HCl) concentration particles mass volume (gas) Mole ratio

7. Titration (acid-base) Standard NaOH solution is placed in the burette 25.0 cm 3 of the unknown HCl solution is pipetted out and placed in a conical flask 2 － 3 drops of an indicator (phenolphthalein) is placed in the conical flask Titration is stopped when one extra drop from the burette causes the indicator to change colour (from colourless to pink) This is the end point of the titration

8. Normal titration Standard solution Solution of unknown concentration (analyte) Back titration Standard solution Excess reagent Unknown (analyte) Known amount of reagent in excess

9. Unknown metal / oxide / carbonate of known mass Dissolve in excess acid of known concentration and volume If necessary, dilute resulting solution Titrate suitable volume of solution with standard solution of alkali Determine total amount of excess acid Calculate amount of acid that has reacted with solid Determine identity of metal / oxide / carbonate