|Objective: This activity will involve measuring the pH of a set of buffered solutions. Once the pH is determined, the concentration of the hydronium ion can be calculated.
Time required: 1 day.
Group Size: 2 students
- Measure the pH of five different solutions.
- Manipulate the data to determine the amount of hydronium ion in each solution, [H3O+1].
Materials Needed Per Group:
Prior Knowledge: The student should be able to exponentiate a number using the formula
- A set of five different buffer solutions
- 5 plastic cups for buffers
- pH probe
- wash bottle
- one cup to serve as a waste receptacle
[H3O+1] = 10-pH
Analysis: Using the pH, calculate the [H3O+1] in each of the buffers.
- Obtain 5 cups, labeled A, B, C, D, E. Each cup contains approximately 10 mL of buffer. Each of the five buffers has a different pH.
- Using the pH probe, students will determine the pH of each solution. The pH of each solution will be recorded in the data table. The probe must be rinsed over the waste receptacle between measurements, using a wash bottle.
Raw Data Table
- The set of buffers will be returned to the lab table to be used again by the next lab group.
Processed Data Table
What is the relationship between the amount of [H3O+1 ] in a solution and the acidity of the solution?