Lab 7

Further Instructions

Data Records & Calculations

Part A

For the table in Part A, watch the video and record your observations for each of the three test conditions. The final table in this section should have a similar appearance to the following:

Part B

Plot all the data points from the video for each of the three tests. Connect the dots.

To convert the markings for mL to inches, use a conversion factor of 150 mL = 2 inches.

For an individual test, calculate the slope between each set of consecutive points. Record the steepest slope as the Fast Rate, record the most shallow slope as the Slow Rate.

Repeat for each test.

Discussion Questions

Part A

1 and 2

For definitions and differences between flocculant and coagulant, see the Wikipeida page on Coagulation (water treatment). Flocculant is can be thought of as a physical net, or web, that catches smaller particles using a polymer.

3

See this image

On the top of the diagram, coagulant is added, neutralizing the charge between the particles, and then flocculant is added. Note that the flocculant does not have trouble bringing clumps of particles together as they do not repel each other.

The bottom of the diagram shows what happens if you add flocculant, then coagulant. The flocculant is blocking the coagulant from bringing larger flocs of particles together due to repulsion forces.

Describe this process in your own words.