Lab Experiments: Making Salted Eggs/Pickled Eggs & Separating Leaf Pigments

[hikki_pop]

these are lab experiments in which i have gathered but i still haven't performed them... can anyone please determine the basic answers or give tips for the upcoming experiments? thanks very much~

Making Salted Eggs/ Pickled Eggs
I. Objective:
To illustrate osmosis/diffusion in making salted eggs/pickled eggs.

II. Materials:
1 kettle
1 plastic bag
2 big, clean glass jar
3 cups salt
1 liter water
1 dozen fresh eggs
a piece of string
vinegar
red pepper
garlic
sugar
III. Procedure:
A. Salted Eggs:
1. Prepare the brine solution by boiling enough water and constantly adding salt until saturation point is reached. This is determined when salt no longer dissolves in water.
2. Allow the brine solution to cool. Pack the eggs in wide-mouthed glass jars or any suitable container.
3. Pour the cold brine solution over the eggs. Put a small plate on top of the eggs to prevent the eggs from floating when pouring water.
4. Cover the mouth of the jar with clean cheesecloth.
5. Keep in cool, dry place. After 12 days, boil an egg and taste it. If the egg is not salty enough, keep the eggs in the solution of one more week. Boil. The salted eggs are now ready to be ready.
B. Pickled Eggs:
1. Hard-boil the eggs in a sauce pan (about ten minutes for chicken eggs).
2. Cool the eggs immediately under running water.
3. While waiting for the eggs to cool, prepare the pickling solution. Add sugar to vinegar (1:1). Put in salt, black pepper, red pepper, and garlic to taste. Simmer for ten minutes.
4. Shell the eggs and pack carefully in glass jars or any suitable container.
5. Pour the hot pickling solution into the jar. The solution should be just enough to cover the eggs. Remove the black pepper.
6. Seal tightly and air-cool. After a week the pickled eggs will be ready.

V. Observations and Questions:
1. What enables the salt particles to pass through the membrane and into the egg?
2. Why did water particles move out from the egg?
3. What process caused the saltiness of the egg?
4. What property of matter enabled the salt to penetrate through, thus making the egg salty?
Separation of Leaf Pigments
I. Objective:
To separate cell substances from the leaves and from each other.

II. Materials:
spinach leaves
acetone
developing solution (8% acetone 92% petroleum ether)
several strips of filter or chromatography paper
fine sand
test tube, 25x200 mm
cork to fit test tube
pipette, with a very fine tip
mortar and pestle
test tube rack
forceps
funnel
cheesecloth 10X10 cm2
scissors
glass making crayon
cleansing tissue
2 pencils
paper clip

III. Procedure:
Caution: Because ether is being used, at no time should there be an open flame in the room.
1. Using the larger test tube, assemble the apparatus as shown in the figure. But do not yet add the developing solution and pigment.
2. Handle the paper carefully with the forceps. Even a small amount of oil from your fingers will affect the results.
3. Adjust the paper in the tube so it does not touch the sides or bottom. Mark on the test tube the level of the lower end of the notch.
4. Remove the paper strip from the hook. Then pour developing solution in the test tube to a depth of 5 mm below the mark that you made.
5. Place the cork with the hook attached (but without the strip of paper) in the test tube. Place the tube in an upright position in a rack. Support the strip of paper across two pencils so that it does not touch the table.
6. Put four of five San Francisco leaves, a little sand, and 10 ml of acetone into a mortar. Grind thoroughly. The acetone now contains extracted pigments.
7. Place a layer of cheesecloth in a funnel. Add a layer of cleansing tissue.
8. Pour acetone into the funnel. Collect the filtrate in the smaller test tube.
9. Using a fine-pointed pipette, place a drop of the pigment extract on the paper between the notches. Allow to dry. Add another drop in the same place, and allow to dry. Repeat until you have placed at least four drops in the paper- one to top of another.
10. When the final drop was dried, remove the cork from the large test tube and hang the strip on the hook.
11. Insert the cork with the paper strip attached into the test tube. Do not allow the pigment spot to touch the developing solution. Adjust the length of the hook to avoid this. Be sure the cork is tight.
12. Watch the developing solution rise. When it almost reaches the hook, remove the cork from the tube. Take the paper off the hook, with the forceps and recork the tube. Hold the paper until it dires.
13. Examine the chromatogram.

IV. Questions and Answers:

(Refer to procedure No. 8 in answering questions No. 1 and 2).
1. What is the color of the filtrate?
2. Is there any evidence that more than one pigment is dissolved in the acetone?
Refer to procedure No. 13 in answering questions 3-8.
3. How many bands of color can you see in the chromatogram?
4. How many bands might be made up of chlorophyll?
5. What other colors can you see in the chromatogram?
6. Why were you unable to see these colors in the leaf?
7. Do you think that all of the leaf pigments were soluble in the acetone? Why or why not?
8. Suggest a hypothesis to explain the change of color that often occurs when a leaf dies.
Refer to procedure No. 12 in answering questions 9-11.
9. From what point did all the pigments start as the developing solution began to rise?
10. When did all the pigments start to move, and when did they all stop?
11. In what characteristic then, must the pigments have differed?

 

[Moonbear]

I think you should first do the experiments, listen to what your teacher teaches about the subject related to each experiment, then if you still have questions, come back and ask about the specific things you need some help understanding. Otherwise, we're just going to spoil all your fun of waiting to see the results for yourself!

 

[ravenprp]

First of all, it's great that you have gathered all the materials and instructions for these experiments. Here are some tips to help you prepare and perform these experiments successfully:

1. Read through the procedures carefully and make sure you understand each step before starting the experiment. If there are any terms or concepts that you are unfamiliar with, do some research beforehand to gain a better understanding.

2. Make sure to follow all safety precautions, especially when handling chemicals like vinegar and acetone. Wear protective gear, such as gloves and safety goggles, and make sure to work in a well-ventilated area.

3. Double check that you have all the necessary materials and equipment before starting the experiment. This will help avoid any interruptions or delays during the experiment.

4. When making the salted eggs and pickled eggs, make sure to use clean and fresh ingredients. This will help prevent any contamination and ensure the success of the experiment.

5. For the separation of leaf pigments, be very careful when handling the paper strips and make sure to avoid getting any oil from your fingers on them. This can affect the results of the experiment.

6. When conducting the chromatography, make sure to follow the instructions carefully and observe the developing solution as it rises. Take note of any changes in color or bands that appear on the paper strip.

7. It's always a good idea to have a control group for experiments, so you can compare your results to a standard. For example, you can leave one egg untreated in the salted egg experiment and compare it to the salted eggs after 12 days.

8. Don't be afraid to ask for help or clarification if you are unsure about any step in the experiment. It's better to be safe and fully understand the procedure than to make a mistake.

Good luck with your experiments! Remember to take accurate observations and record your results carefully. Have fun and enjoy the process of learning through experimentation.