Titrations

1. Titrations • Titrations are used to measure exact amounts of reactants in a reaction and use the information to find unknown concentrations. 12 Chemistry 2.2 quantitative chemistry CR 07

2. Titration Equipment • Electronic Balance • -used to • accurately • weigh • solute 12 Chemistry 2.2 quantitative chemistry CR 07

3. Volumetric Flask • - used to make exact volumes of solution 12 Chemistry 2.2 quantitative chemistry CR 07

4. Pipette • -used to measure and transfer a known volume of solution 12 Chemistry 2.2 quantitative chemistry CR 07

5. Conical flask • - used to mix solutions • (reaction vessel) 12 Chemistry 2.2 quantitative chemistry CR 07

6. Burette • - used to exactly measure the volume of solution that has reacted –this is known as the titre 12 Chemistry 2.2 quantitative chemistry CR 07

7. From known to unknown • In a titration a knownvolume • of solution with a known • concentration is used to react • with a solution of unknown • concentration. • Using c = n/v the unknown • concentration can be calculated. 12 Chemistry 2.2 quantitative chemistry CR 07

8. The known – standard solution • Making a solution of known • concentration is done by • Measuring an exact mass of • solute and mixing it with an • exact volume of water in a • volumetric flask. 12 Chemistry 2.2 quantitative chemistry CR 07

9. Making a Standard Solution • Weigh solute exactly • Mix in beaker with distilled water • Pour into volumetric flask 12 Chemistry 2.2 quantitative chemistry CR 07

10. Rinse beaker into volumetric flask with distilled water • 5. Mix by swirling volumetric flask 12 Chemistry 2.2 quantitative chemistry CR 07

11. 6. Make the volume up to the exact amount by adding water drop by drop • The volumetric flask must be • on a flat surface and at eye level. • AND the bottom of the meniscus • must sit on the line. 12 Chemistry 2.2 quantitative chemistry CR 07

12. Standard solution • If the solution level goes over • the line on the neck of the • volumetric flask then the • solution is no longer a standard • solution and the whole process • must start again. 12 Chemistry 2.2 quantitative chemistry CR 07

13. Transferring • A pipette is used to transfer • the set volume of the solution • to the reaction vessel • (conical flask). • *eye level 12 Chemistry 2.2 quantitative chemistry CR 07

14. Emptying the pipette • Touch end of pipette on side of vessel • There should be some liquid left in the bottom 12 Chemistry 2.2 quantitative chemistry CR 07

15. Aliquots • The measured amount of • solution that is transferred to the • conical flask is called an aliquot. • Indicator is added to the • aliquot so that end pointof the • reaction can be determined. 12 Chemistry 2.2 quantitative chemistry CR 07

16. Burette • The burette is rinsed with the solution it will contain and then filled and read at eye level 12 Chemistry 2.2 quantitative chemistry CR 07

17. The Reaction • The reaction occurs in the conical flask, which is swirled gently under the tap. After a ‘rough’ titration has been done solution is added drop-wise when near the end point. 12 Chemistry 2.2 quantitative chemistry CR 07

18. Titrations • Known usually goes into burette and unknown into conical flask 12 Chemistry 2.2 quantitative chemistry CR 07