Advanced Chemistry Lab: Stong/Weak Acids & Bases
Research Question How are pH and concentration correlated in strong vs. weak acids and bases?
Learning Target I can determine the concentration of an acid or base experimentally using titration and perform associated calculations.
Safety Considerations - Safety glasses should be worn at all times
- Acids and bases are hazardous and should be handled accordingly
- Follow all written and verbal instructions
Data to Collect - Identify of each solution (M, formula) for all
- Concentration of each solution (expressed as 1x10-n M)
- pH of each solution
- [H+] of each solution
- pOH of each solution
- [OH-] of each solution
- Whether it’s ‘strong’ or ‘weak’
Procedure Outline - Obtain 0.1M solutions of a strong acid (HCl), strong base (KOH), weak acid (acetic acid), and weak base (NH4OH).
- Working in microfuge tubes, perform a serial dilution with each solution so you end up with 0.1M, 0.01M, 0.001M and 0.0001M solutions for EACH solution provided (4 solutions x 4 dilutions = 16 tubes total).
- Make sure your tubes are labeled as you go!
- Determine the pH of each solution by adding ONE DROP to a strip of pH paper. (alternatively, you may use the SPARK pH probe to determine pH)
- Then, calculate the [H+] for each solution.
- Calculate the pOH and [OH-] of each solution.
- Identify the solution as ‘strong’ or ‘weak’.
- Create a total of 4 line graphs; two for the acids (one strong, one weak) and two for the bases (one strong, one weak). Graph the concentration of the acid (expressed as 1x10-n) vs. [H+]. See example below.
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