LEARNING OBJECTIVES:
1) Define the terms indicator, titration, endpoint (equivalence point), standard solution.
2) Know the color change of litmus, phenolpthalein and bromthymol blue in acids/bases.
3) Understand how to titrate a solution to determine the concentration of an unknown (including making a calibration curve).
4) Be able to calculate the concentration of an unknown solution from titration data.
Introduction to titration using an acid and a base with an indicator.
Show indicators: bromthymol blue (blue - base) --> (yellow - acid)
phenolpthalein (colorless - acid) --> (pink - base)
universal indicator (ROYGBIV) pH 4-10
litmus paper (red --> blue...base) and (blue --> red...acid)
pH paper - use glass rod to touch paper (don't dip paper into solution).
Demonstrate titration using 0.3 M HCl to titrate an unknown base (NaOH).
Show how to read buret and record data.
Calculate the concentration of the base (M1V1 = M2V2).
Show students the actual value of base and it will be same as what is calculated.
Video on Titration: Setting Up and Performing a Titration video:
How to make a calibration curve
LAB: Students will collect 5 data points using 0.3 M acid and an unknown concentration of base.
Students will graph acid vs base concentration on a graph and calculate the Molarity of the base for each trial (reporting the average molarity).