Titration

Question 1

Titration

Answer 1

the process of adding an equivalent amount of titrant to react with the analyte

Question 2

Titrant

Answer 2

-a substance added to a liquid in measured amounts to determine the concentration of another substance in the liquid
-By measuring volume of titrant added, you measure moles of titrant added
-moles of x added= M(x)V(titrant in L)

Question 3

Analyte

Answer 3

a chemical substance that is the subject of chemical analysis

Question 4

Indicator

Answer 4

a substance that changes color to signal the end of a titration

Question 5

Equivalence point

Answer 5

-the point at which the amount of titrant added exactly consumes all of the analyte
-color should be mix of base and acid of indicator

Question 6

End point

Answer 6

the point at which the indicator signals the end of the titration

Question 7

Titration steps

Answer 7

-Make sure buret is clean
-Condition clean buret with several mL of titrant 2-3 times
-Fill the buret with titrant (not necessarily to 0.00 mark) and drain some titrant out to get rid of bubbles trapped in valve
-Do not leave funnel hanging on top
-Take initial buret reading to 2 decimal places
-Add titrant while the analyte solution is stirring at moderate rate
-When the end point is near (when transient color of indicator stays for a longer period of time), rinse the wall of the flask (that holds analyte solution) with d-H2O (from wash bottle) and add titrant dropwise
-When the end-point color stays for more than 30 seconds, take the final buret reading

Question 8

Graphing titration data (titration curve)

Answer 8

-All graphs must be plotted on a computer
-Total volume of titrant added= final reading - initial reading
-Enlarge part of titration curve to obtain VE
-Estimate position of equivalence point:
read y-axis to the same SF displayed on the pH meter (minor gridlines every 0.1 unit)
Read x-axis to same SF displayed as a buret (minor gridlines every 0.1 unit)
-Moles of titrant added= MNaOHVE = moles of HA in beaker

Question 9

Back titration

Answer 9

instead of analyzing concentration of analyte in flask, you analyze concentration of titrant in buret

Question 10

How to find M of analyte

Answer 10

-measure amount of titrant (L) added at equivalence point
-convert amount of titrant to moles using M and L
-this is equivalent to the amount of moles of analyte
-divide moles of analyte by original volume of analyte to get M