P8. saponification

Introduction:

• Let's take a saponification. We will create soap from olive oil (a Triglyceride) and a strong base (NaOH). The base plus lipid react and create soap.

Materials:

1. 600mL Beaker
2. Spatula
3.  Watch glass 
4. Stirring rod
5. 2 beakers 250mL
6. electronic balance
7. Gloves
8. Safety goggles
9. Hot plate
10. 32g NaOH
11. 90mL H2O
12. 270mL Oil

Procedure:

• We take 32 grams of NaOH in 90 mL water and mix. Add 270 mL of oil and mix until well dissolved. We can help a heat source. Once dissolved, add scents to smell the soap. Finally pour our solution into a mold and let stand for several days until they solidify. We remove the mold and you're ready to use this soap to wash our hands! 

Results and observations:

This picture was taken by Liza: http://lmsciencelab.blogspot.com.es/

P7. Lipids properties

Introduction:

Let's see how does a couple of drops of oil when the strips in water, ethanol and Esther.

We will dtermine lipids with Sudan III dye for different type of milk. 

Let's see what effect the soap when you add to the mix water and oil.

Objectives:

• Test the solubility of lipids.
• Identify lipids in liquids compounds.
• Understand what are the effect of detergents.

Material:

• Test tube rack
• 250mL beaker 
• Water
• 6 test tube
• Cellulose paper
• Dropper
• Scissors
• Glass rod
• Olive oil
• Soap
• Milk with different fat content (semi-skimmed, full-cream...)
• Petroleum ether
• Ethanol
• SudanIII

Hypothesis:
Sudan III will dye the lipids of the milk. Full-cream milk containe more lipids so it will be more stained than skinned milk.
The oil and water form a lipid monolayer, and the ether will dissolve the oil, and ethanol and water form micelles.
Oil and water do not mix oil will form a monolayer.
Lipids are insoluble in water and soluble in organic compounds.

Procedure:

• Take three test tubes and add 2 mL of milk in each tube. In a whole milk, semi-skimmed milk in another and the last soymilk. Once we have milk in each tube add two drops of Sudan III staining with increased amount of milk lipids. Observe what happens.
• Take another 3 test tubes and we put in a 1 mL of water, another 1 mL of ethanol and 1 mL of the final ether. Add in each two drops of oil. Observe how they act and every oil solvent.
• Take a beaker of 250 mL and 100 mL of water are put. Add oil. Look what happens. Having observed the results, add soap. Stir, we see now?

Comments and conclusions:

Sudan III reacts more Sudan III.Full cream
The solubility of water in the ethanol and ether mixed with oil.
The right and the water does not dissolve, because oil is a lipid and lipid do not dissolve in water. The oil will form a monolayer on the surface of the glass, and when you add oil soap grouped to form droplets.

First test tube water and oil-----> don't mixt
Second test tube, oil and ethanol-----> oil formed micelles
Third test tube, oil and ether-----> ether (organic dissolvent) can disolve

Questions:

1.- From your observation, wich compounds can dissolve lipids? 

Ether 

2.- Do the oil and water mix? What can you conclude about the polarity of the oil if you know that water is polar? 

No, they don't.

Apolar (no polar)

3.- Why is liquid the olive oil at room temperature? And why not the lard?

Oil is the fat acid insaturated

4.- Why does the lipid leave a translucent spot on paper? 

The lipid don't evaporate, and the water evaporate.

5.- Wich type of milk contains more lipids? Why?

 Full-cream milk, because they take away the semi-skimmed milk fats.

6.- Did the oil and water mix when you added the soap?

No, they didn't.

7.- What did the soap do to the fat? 

Separated in micelles.

8.- Can you think about process and locations were compounds like the soap would be important to an animal? 

Bile acids.

P6. Fehling's test: reducing sugars

Introduction:

From Fehling's solution we will identify whether or not a substance is reductive, ie if you have a free OH group at carbon 1 or 4 carbon.

Objectives:

• Identify reducing sugars.
• Comprehend redox reactions.
• Understand the relation between structure and reducing ability of some sugars.

Materials:

1. Test tube rack
2. 10mL pipet
3. Distilled water
4. 5 test tubes
5. 5 spatula
6. Lactose
7. Maltose
8. Glucose
9. Sucrose
10. Starch
11. Fehling's A and B solutions
12. HCl

Procedure:

• .Take five test tubes and we put 2 mL of distilled water. In each tube add a Glucose, Maltose another in another Sucrose, Lactose and another in the last starch. Add the Fehling's solution and hope for a while. Those who have changed color are reducers.

Comments:

• Sucrose does not react with Fehling's solution because it includes a furanose and pyranose.

Conclusions:

Questions:

1-From your observations and the structures of the sugars given above, indicate which functional group in the sugar molecules reacts with Fehling's reagent.

The OH group is the one that reacts with Fehling's test because when it's free the sacharide will have the reducing power.

2-Compare the results you obtained for the Fehling's test of starch and Fehling's test of hydrolyzed starch. Explain your results.

Starch has no reducing power as it is a polysaccharide, and has a very long chain of carbons.

3-Would have you obtained a Fehling's positive test if you had hydrolyzed the sucrose? Why? 

Yes. 

4-What does "reducing sugars" mean? 

Is the one that reacts positive to the Fehling's test. 

P5. Saccharides properties

Introduction:

Today we will learn to differentiate monosaccharides, disaccharides and starch from its taste, if color, solubility and test lugol are crystalline or not. Performing these tests can know how is glucose, a malty, one sucrose, lactose and starch one.

Objectives:

• Identify different sugars from its properties.
• Differentiate mono and disaccharides
• Understand the relation between structure and some properties.

Hypothesis:

• All monosaccharides are crystalline, all monosaccharides and disaccharides are water soluble and are transparent, however, polysaccharides (starch) are not soluble nor transparent. Lugol test only stain the starch.

Materials:

1. Test tube rack
2. 10mL pipet
3. Water
4. 5 test tubes
5. 1 dropper
6. 5 spatula
7. Lactose
8. Maltose
9. Glucose
10. Sucrose
11. Starch
12. Lugol's iodine
13. Distilled water

Procedure:

• Take glucose, maltose, sucrose, lactose and starch. First put into test tubes 5 5 mL of distilled water and add solutes (G, M, SU, L, S) in each of the tubes. We look at whether or not they are sweet, tastings. Then take a microscope and observe whether or not crystallize. Let us have the color (white or creamy). If you are soluble or not. As nem doing this, we are pointing in the results table.
• Once we arrive at the test Lugol, add two drops of Lugol's iodine and heat. If changes coor (a black-purple) means it is starch. Lugol test only identifies the starch.

Comments:

• All polysaccharides are NOT sweet
• All NON-soluble polysaccharides

Conclusions:

• 
  

Questions:

1.- Write the empirical formula of each saccharide that you have use. Show structures of the five     saccharides. Classify each one in one group: mono, oligo or polysaccharide.

        Glucose: C6H12O6 / monosaccharide.

        Maltose: C12H22O11 / oligosaccharide.

        Sucrose: C12H22O11 / oligosaccharide.

        Lactose: C12H22O11 /oligosaccharide.

        Starch: C6H10O5 / polisaccharide.

2.- Which of the monosaccharides are aldoses and which are ketoses?

       Aldoses: glucose, maltose, lactose, starch.

       Cetoses: sucrose.

3.- Which bond links monosaccharides?

       Oligosaccharides.

4.- Which saccharide/s is/are sweet? Is this property related to the structure of the molecule?

        Glucose,sucrose, maltose.

5.- Which saccharide/s is/are soluble? Is this property related to the structure of the molecule?

        Starch, because is a big molecule. (Pes molecular gran)

6.- Which saccharide has reacted with Lugol's iodine solution?

        Starch

7.- Which kind of foods contains starch?

        Cereals, pasta, rice, legums...                             

8.- Calculate the energy from the nutrition facts labelfrom a cereal

• Calculate the energy that comes from the saccharides.

              23x4,2= 96.6Kcal

P4. pH

Introduction:

• We will measure the pH of: HCl, vinegar, wine, tomato, coffee, distilled water, soap, read and NaOH. We will examine if your pH is acidic, basic or neutral. Also there are pH will look at different concentrations of lemon juice with a pH meter accurate.

Objectives:

1. Measure different pH values of organic and inorganic solutions.
2. Prove different methods of measuring pH.

Hypothesis:

• Each substance has a different pH. 
• The higher the concentration of lemon juice there is in a solution with distilled water, the pH will be more acidic.

Materials:

• Distilled water
• milk
• wine
• lemon
• tomato
• cokke
• carbonated beverage
• 10% NaOH solution
• 10%HCl solution
• NH3 solution
• Soap solution
• Universal indicator paper (strips)
• pH-meter
• Acetic acid
• tongs
• 8 x 100mL Beaker
• 5 test tubes
• Test tube rack
• 10 mL pipet
• Funnel
• Graduated cylinder

Procedure:

• Enter a beaker HCl concentrations, vinegar, wine, tomato, coffee, distilled water, soap, and NaOH read. Looking pH with universal indicator paper pH. We note the acidity of each solution. Look if they have a basic or acidic pH.
• Take 5 test tubes and indicated. The first tube "B", the second "A1", the third "A2" on the four "A3" and the fifth "A". In the tube "B" Enter 10 mL of lemon juice in the tube "A1" Enter 5 mL of lemon juice plus 5 mL of distilled water in the pipe "A2", introducing 2.5 mL of lemon juice over 7.5 mL of distilled water in the pipe "A3" Enter 1.25 mL of lemon juice and 8.75 mL distilled water. In the pipe "A", enter 1.25 mL lemon juice, nothing more. Each test tube will have a total volume of 10 mL, except the tube "A". With an electronic pH meter pH house look dissolution.

Comments:

• To look at the pH of each substance to be used universal pH indicator paper or a electronic pH meter.

Conclusions:

• The test tube with the highest concentration has a higher acidity which has less concentration.

Questions:

1. Which of the solutions gave an acid pH? 

  

   -Solution B

2.- Which of the solutions was alkaline?

Soap, bleach and NaOH.

3.- Which of the solutions were neutral? Did you expect this results? Explain.

Distilled water, because it has the same concentration of H+ and OH, and thats why we expect that water is with a pH neutral.  

                                                                                                  

4.- How does a pH of 3 differ from pH of 4 in terms of H+ concentrations?
10 times large value.

5.- In the second part of the experiment, you have compared the pH of the same product (lemon juice) in different concentrations. In this case explain:

• Which is the dependent variable? The pH.
• Which is the independent variable?The concentration of lemon juice.
• Which is the problem that we want to solve? The problem that we want to solve is equalize the concentrations.
• Which is the control of the experiment? The control is the test B.
• Write the results and conclusions of your experiment: The pH is very similar on the all concentrations, but the normal is that the pH depends of the protons concentrations. 

6.- Which pH do you think that gastric juices might have? Why? Do you think that intestinal pH has the same pH? Why?
They have an acid pH because its used to improve food digestion. I think that all intestinal pH are acid.

7.- Which pH do you think that blood might have? Why?
The blood have an neutral pH, because if is hypotonic the cell bloat, if is an hypertonic the cell crease. The pH causes it to keep the concentration, because we could die.

8.- What is acid rain? Which are the consequences in the ecosystems and how is its formation pattern? Is rain Barcelona acid or alkaline?

The acid rain is a phenomenon, that have a pH levels lower than normal. Is mainly due to the mixture of water with molecular products of sulfur and nitrogen in the combustion incurred, such as nitrous oxide NO2, NO3 nitric oxide or sulfur dioxide SO2 which when combined with the water generated nitrous acid HNO2, HNO3 nitric acid and sulfuric acid H2SO4. 
Acid rain can have harmful effects on plants, animals and buildings. Causes corrosion of metal structures such as bridges or erosions in stone buildings. It also burns the leaves of vegetation and ecosystems it affects mainly vegetables, such as forests, but can also affect lakes and reservoirs acidifying them.
In Barcelona this rain, is alkaline. 

L3. Osmosis

Introduction:

This is a lab on osmosis. Today we will see how a hypertonic medium and a hypotonic environment. We will also see the difference between the concepts isotonic, plasmolysis and turgidity.

Objectives:

1.      Know about the osmosis phenomena.

2.      Understand the process of osmosis in plasmatic membranes.

Hypothesis:

·       

       When you add a lot of salt in a medium, this wrinkle, leaving ana water. When you add a quantitad of distilled water in a medium swell.

Materials:

·         Egg

·         Potato

·         Salt

·         Distilled wáter

·         Acetic acid (or vinegar)

·         Spatula

·         600 mL Beaker

·         3 Clock glass

·         Pen

·         Spoon

·         Knife

Procedure:

·          Cut three pieces of potato peers. By adding a high concentration of salt, the other add distilled water, and the third adds nothing. Let us spend a while to look after a while each sample. 

                      

        Put an egg in a Beaker 600 mL of distilled water. Let us spend a couple of days. Having spent time look egg.

Comments:

·          The potato has been inflated with distilled water, salted potato has wrinkled potato has nothing, as usual. There    is an acute process of osmosis.

Conclusions:

The potato has been inflated with distilled water, salted potato has wrinkled potato has nothing, as usual. There is an acute process of osmosis. 

The egg has been inflated. He suffered a turgidity. 

Questions:

·         Egg experiment:

1.       What is happening  when the shells are soaking of acetic acid?

-          CaCO3 + CH3COOH                 Ca (CH3COO)2 + CO2

2. Write the results of the dimensions and weigh of the egg before and after immersing it in distilled wáter. Write and draw a simple diagram of the water direction.

·         Potato experiment:

3. Explain the results of this experiment:

- The potato has been inflated with distilled water, salted potato has wrinkled potato has nothing, as usual. There is an acute process of osmosis. 

      The egg has been inflated. He suffered a turgidity.

4. Why have we left the first slice without any treatment (salto r distilled water)?

- To compare the results

5. Which are the dependent and independent variables?

-        Dependent: Turgidity of the potato, the presence of water in the cells

-        Independent:salt, distilled water

·         General questions:

6. How can you explain (through osmosis) the ability of plant roots to draw water from the soil?

- The salt concentration of the cells is higher, so water tends to enter.

7. What will it happen if a saltwater fish is placed in a freshwater (low concenttration of salts) aquarium?

- It will die

8. Look the image you have below and explain what is happening to the erythocytes in each situation:

       1) Plasmólisi

       2)Control

       3)Turgid