What is a Potentiometric Titration? Potentiometric titration- uses a ___________ to determine ____________ Potentiometer-measures _________________________ pH meter- a type of _____________ – measures ________ ______________ and gives us_____________ Our pH meters have _____________ that consist of ___________________________ and _______________ to allow exchange of ions to be detected You must first _____________________ the pH meter (just as we did with the spec 20s last semester) to let it know what potential changes are equivalent to particular pHs. You should always calibrate instruments _________ _________________________________________________

Why Potentiometric? ADVANTAGES: –If you have multiple unknowns with different ____________________ and want to identify each –______ solutions that would interfere with detection of colored indicators –Better ____________________ –You can graph to determine endpoint instead of relying on visual detection DISADVANTAGES: –_______________ –$- pH meters much more expensive than colored indicators –Cannot detect when you are _________________________________

Standardization of HCl Primary vs. Secondary Standards –1° = a reference standard of known ________ __________ You can know EXACTLY how many _________________ you have –2° = ___________________________. You use the _____ standard to determine concentration in order to use this standard to determine amount of something else.

Standardization of HCl cont’d. Calculations Known: Want:

Unknown Goal: ________________________________________ __ Known: