Day 3 Acid-Base

Other methods of determining pH

If molarity is not known, pH can be determined by… Acid-Base Indicators pH meter Titration

Indicator Solutions Change color depending on pH of test solution

Indicators

Indicators

Indicators

Problems with indicator solutions: If you have a colored solution Approx pH value not exact Temperature affects color 

pH meter

pH meter consists of a measuring probe electronic meter: measures & displays the pH reading have to calibrate probe

Titration Use Buret, Erlenmeyer flask, & indicator Use M1V1 = M2V2 to determine molarity of unknown

Titration

Titration

Answer the following questions while watching the video clips: Where do you read/How do you read a burette? What hand do you use to swirl the Erlenmeyer flask? What hand do use to adjust the burette? When do you know you are getting close to the endpoint? How is the standard solution added as you get close to the endpoint? When do you know you have achieved the endpoint?

Titration Video Clip #1 (3:15) Titration Video Clip # 2 ( 6:07)

Now, do the titration pre-lab

Tonight’s Homework