Foul WaterMIXTURES LAB

Hand in when entering the lab. No admittance without a completed PreLab. 1. What three water purification techniques will you use? 2. Define "Filtration". Define "Filtrate". Define “distillation”. 3. What will you use to measure the volume of your foul water sample? 4. How do you support a funnel? 5. Oil and water separate into distinct layers, which substance will you drain out of the

funnel? 6. After separation, what will you do with the oil portion? 7. After separation, what will you do with the water portion? 8. How will you make a sand filter? 9. Why should the sand and gravel be pre-moistened? 10. What is purpose of charcoal adsorption? 11. If your filtrate has bits of charcoal in it what do you do? 12. What do you do with your purified water? 13. What is the last thing you must do before leaving the lab?

Lab Purposre and Introduction Purpose: to purify a sample of foul water Introduction: During this experiment, you will use four

water-purification processes: • Oil-water separation • Sand filtration • Charcoal adsorption and filtration After each process, you’ll make some observations and

record them neatly in a table. Please read the instructions carefully before you begin!

Safety Precautions: Do not taste the foul water samples under any circumstances. Wear safety goggles at all times.

Materials:

Ruler 100 mL graduated cylinder2 beakers (100 mL) 1 Erlenmeyer Flask

(250 mL)Ring Stand w/ Ring FunnelClay triangle Filter Paper

Paper clip DropperStyrofoam cup Lab Apron

Before you begin:1. Copy the data table. Obtain a sample of foul

water from your teacher. 2. Measure its volume precisely with a

graduated cylinder. Record the actual volume of the water sample (with units) in your table.

3. Pour the foul water into an empty beaker. Examine the physical properties of your sample: color, clarity, odor, presence of oil and presence of solid. Record all observations in your table.

Part 1: Oil-Water Separation4. Allow the foul water to sit undisturbed in its

beaker for 1-2 minutes. During this time, any oily residue should float to the top of the sample.

5. Using a plastic dropper, carefully remove the oily residue while removing as little water as possible. POUR USED OIL IN A WASTE BEAKER – NOT IN THE SINK!

6. Observe the properties of your water sample and measure its volume in a clean graduated cylinder. Record all results in your table.

7. Using a straightened paper clip, poke several small holes in the bottom of a paper cup.

8. Using a ruler, add pre-moistened gravel and sand layers to the cup as follows: a. FIRST LAYER: 1 cm of gravel

b. SECOND LAYER: 2 cm of sand

c. THIRD LAYER: 1 cm of gravel

(The bottom layer of gravel prevents the sand from washing through the holes. The top layer of gravel keeps the sand from churning up when the water sample is poured in.)

9. Place your sand filter on top of a clean 100 mL beaker. Gently pour the foul water through the filter. Catch the filtrate (filtered water) in the beaker as it drains through.

Part 2: Sand Filtration

Part 2: Sand Filtration10. Dispose of the used sand and gravel

according to your teacher's instructions. Do not pour any sand or gravel into the sink!

11. Observe the properties of your water sample and measure its volume in a clean graduated cylinder. Record all results in your table. Save the filtered water sample for the next procedure.

Part 3: Charcoal Adsorption/Filtration 12. Obtain a 250 mL Erlenmeyer flask and add small spoonful of

charcoal. 13. Pour the water sample into the flask and swirl vigorously for

20-30 seconds. 14. Fold a piece of filter paper as shown in the diagram below.

Place the folded filter paper in a funnel. Hold the filter paper in position and wet it slightly so it clings to the inside of the funnel cone.

Part 3: Charcoal Adsorption/Filtration 15. Place the funnel in a clay triangle supported by a ring clamp.

Lower the ring clamp so the funnel stem extends a few centimeters inside a 100-mL beaker. (See diagram).

16. Then gently pour the water sample (with charcoal) through the filter paper. Keep the liquid level below the top of the filter paper. Liquid should not flow through the space between the filter paper and the funnel.

17. If the filtrate is darkened by small charcoal particles, refilter the liquid through a clean piece of moistened filter paper.

18. Observe the properties of your water sample and measure its volume in a clean graduated cylinder. Record all results in your table.

19. Pour the used charcoal in the container provided by your teacher.

20. Pour your water sample into a clean 100 mL beaker and measure the amount remaining. Wash all glassware, return all materials, and wipe down your lab table. Be sure to wash your hands before you leave class.

Data Table

  Color Clarity Odor Oil Present?

Solids Present?

Volume (mL)

Before treatment

           

After oil-water separation

           

After sand filtration

           

After charcoal            

Calculations:1. Find % “pure” water from original “foul” water sample:

% pure = final volume x 100 = _______ml x 100 original volume ml 2. Find the water volume lost during purification:

Original _________Final -________

= mL lost during purification 3. Find % water lost during purification: (use calculation #1 as your model and your answer from calculation #2).

Foul Water Lab – Final Calculations and Questions1. What percent of your original foul water sample was recovered at the end of the experiment?

Show work!

2. What percent of your water sample was lost during the experiment? Is this an acceptable margin of error? Explain.

3. Estimate the total time you spent purifying your water sample _______________. In your opinion, were you able to purify a sufficient amount of water in that amount of time? Explain.

4. Describe the steps needed to perform a distillation. Sketch a diagram and clearly label the key steps involved.

5. Municipal water treatment plants do not use distillation to purify water. Why do you think this is true?

6. What does sand filtration remove from a dirty water sample?

7. What does charcoal adsorption/filtration remove from a dirty water sample?

8. What would distillation remove from a dirty water sample?