10.3 Acid- Base Stoichiometry: TITRATION

What is a titration? A procedure used to determine the concentration of a solution using a standardized solution (i.e. a solution with a known concentration)

Components of a Titration Sample = the solution with the unknown concentration in the flask Titrant= the standardized solution gradually added to the flask of the unknown solution Burette= a tube with 0.1 mL divisions that measures the volume and holds the titrant. Has a valve to control the volume of titrant leaving the burette.

Apparatus

Equivalence Point The point during an acid-base titration when neutralization is complete (i.e. the acid-base mole ratios are equal) The pH rapidly increases near the EP, as shown on the titration curve.

End Point NOT the same as equivalence point This is when a single drop of titrant permanently changes the colour of the sample of unknown concentration Result of adding a very slight excess of titrant

Good vs. Bad Endpoint

How to Perform a Titration See page of your textbook Set up the titration equipment as shown on page 479 Put the unknown solution in the flask  IMPORTANT—add an appropriate indicator to the flask Record the initial volume of the standard solution in the burette Open the valve and add the standard solution in the burette drop-by-drop to the flask until you see a sudden colour change (end point) Repeat the process 3 times for accuracy and average the volume to calculate the concentration of the unknown solution

Get it? Titration Demo 8UiuE7Xx5l8

Example Using Experimental Data A mL sample of H 2 SO 4 (aq) is titrated with a mol/L of NaOH. Determine the amount concentration of H 2 SO 4 in the flask.

Homework Read pp. 476 – 485 Answer p. 485 #