Open your lab notebook to your table of contents and fill in the information

below

Date Title Partners Pages7 October Diffusion

& pH(will be assigned)

Turn to the next blank page in your lab notebook and write the following:

Title: Examining the rate of diffusion of unknown concentrations of acids and bases, into dH2O, using Vernier Probes.

Materials

• Each group will have:• 1 probe• 1 beaker of dH2O• 1 sample to test• 1 clip to hold the sample

Write the following in your notebook.

• Sample number: __________

• Color of sample: ___________

• Initial pH of dH2O: __________

• Final pH of dH2O: __________

Sample#

Slope of the line (m)

Molarity

12345

IMPORTANT!

• These substances can burn your skin• Do not get the Vernier probe bases wet• Be gentle with pH probes

Setting up your probe

• Give the probe to one person in your group.• File, New• Click Mode• Click the white box next to “rate.” Type in 10• Click the white box next to “length.” Type in 5• Using the drop down menu and select “min.”• Click “OK.”

• Plug in the pH probe into the top of the base where it says “CH 1.”

• Place the base into the plastic bag• Unscrew the tube at the end of the pH probe• Place the probe into a beaker of dH2O

• Watch the red box on the screen until the pH reaches between 7.3 and 7.5

• Set up your sample• Press the play button on the screen of the

base.

At the end of 5 minutes

• Graph button• Analyze• Curve fit of pH• Choose fit, linear• Write down the “m” number

Sample# Slope of the line (m)

Molarity

1 2M HCl

2 1M HCl

3 Water

4 1 M NaOH

5 2 M NaOH

What is Molarity?

• Molarity is a measure of grams of a substance per liter.

• M = g/L• The higher the Molarity, the higher the

concentration of a substance.

Analysis

• Draw the general shape of each graph• How does Molarity relate to rate of diffusion?• For each solution was the water hypotonic,

hypertonic or isotonic to the sample in the bag?