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