L8. SAPONIFICATION

1. 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.


2. Materials:

-600mL Beaker

-Spatula

- Watch glass 

-Stirring rod

-2 beakers 250mL

-electronic balance

-Gloves

-Safety goggles

-Hot plate

-32g NaOH

-90mL H2O

-270mL Oil

3. Procedure:

We take 32 grams of NaOH in 90 mL water and mix. 

Now we add 270 mL of oil and mix until well dissolved. We can help by heating it. Once dissolved, we add scents so the soap smells better. 

Finally we pour our solution into a mold and let stand for several days until it becomes solid. 

Finally we remove the mold and you're ready to use this soap to wash our hands. 

4. Results and observations:

L7. LIPID PROPERTIES

1. Introduction:

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

-As the dye (Sudan III), we determine quantitad lipids that are in each type of milk, the more fat there are more change color.
-Let's see what effect the soap when you add to the mix water and oil.

2. Objectives:

-Test the solubility of lipids.

-Identify lipids in liquids compounds.

-Understand what are the effect of detergents.

3. 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


4. Hypothesis:The most amount of milk fat (full cream milk) tenyirà more than that unless you cuantitat lipid (skimmed).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 and form a monolayer, and the ester oil if you mix and oil and ethanol and oil do not mix form micelles.

5. Procedure:
1- 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.

2- 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.

3-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?


6. Comments and conclusions:
Sudan III react more with the most amount of milk lipids, the whole milk.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 mixtSecond test tube, oil and ethanol-----> oil formed micellesThird test tube, oil and ether-----> ether (organic dissolvent) can disolve

7. Questions:
1.- From your observation, wich compounds can dissolve lipids? Ether can dissolve lipids

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 mix. So we ca conclude that the oil is apolar (non polar)
3.- Why is the olive oil liquid at room temperature? And why not the lard?Because oil is an insaturated acid, and lard not.

4.- Why does the lipid leave a translucent spot on paper? Because even if water has evaporate the lipid don't evaporate.

5.- Wich type of milk contains more lipids? Why? Full-cream milk, because in the experiment we have done we can see that they have more fat than the other milk types.

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? Soap separated in micelles the fat.

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

L6. Fehling's test: Reducing sugars

1. Introduction

Fehling's solution is a chemical test used to differentiate between reducing and non-reducing sugars. This test is based on the reaction of a functional group of sugar molecules with Fehling's reagent. Fehling's regent has two separate solutions: Fehling's A and Fehling's B. 

Fehling's A: is a blue aqueous solution of copper(II) sulphate. 

Fehling's B: Clear and colourless solution of a potassium sodium tartrate and sodium hydroide.

When both mixtures are mixed a deep blue colour solution can be seen. 

Some sugars ara capable of reducing copper II ions to copper I ions. This reducing ability is useful to classifying sugars. When the sugar to be tested is added to the Fehling's solution and the mixture is heated , some sugars can be oxidized and the Fehling's mixture can obtain this electrons.

2.Objectives 
- Identify reducing sugars.

- Comprehend redox reactions.

- Understand the relation between structure and reducing ability of some sugars.

3. Material

- Test tube rack

- 10mL pipet

- distilled water

- 5 test tubes

- 5 spatula

- Lactose

- Maltose

- Glucose

- Sucrose

- Starch

- Felhibg's A and B solutions

- HCl

4. Procedure

1. Take 5 test tubes and label: G,M,S,L,ST.

2. Put 2ml of distilled water inside each tube.

3. With different spatulas put a small amount of each sugar. Dissolve the sugar.

4. Add 2ml of Fehling's A solution annd then Fehling's B. 

5. Place each test- tubes in a boiling water bath (250 ml beaker on a hotplate stirrer)

6. Observe what is happening.

Starch hydrolysis:
Hydrolysis is the reaction of a compound with water. As you know, starch is a polymer, consisting of many units of aldo-D-glucose covalently linked together.
7. Place 2 mL of 1 % starch in a test tube and add o,5 mL of 3M HCl. Mix and place this mixture in a boiling water bath for 10 minutes.
8. After 10 minutes, remove the tube from the water bath and let it cool. Neutralize this solution with 1M NaOH and mix well.
9. Transfer 8-10 drops of this solution to a small test tube.
10. Add 1mL of Fehling's A solution and 1mL of Fehling's B.
11. Heat for a few minutes in a boiling water bath.
12. Record your observations. Compare the results of this test with your results for unhydrolyzed starch in the step 1 of this experiment.
13. You can test the absence of starch with iodine solution too!!

5.Questions 
1. From your observations and the structures of the sugars given above, indicate wich functional group in the sugar molecules reacts with Fehling's reagent.
2.Compare the results you obtained for the Fehling's test of starch and Fehling's test of hydrolyzed starch. Explain your results.
3.Would you have obtained a Fehling's positive test if you had hydrolyzed the sucrose (as you have done with starch)? Why?
4. What does "reducing sugars" term mean?

-Maltose and glucose have reducing power
-Sucrose and Starch don't have reducing power

6.Results

L5. Saccharides properties

1. Introduction
Saccharides are organic molecules consisting of C, H and O atoms. They area divided in three groups:
-Monosaccharides: formed by a linear carbon chain, are the building blocks of oligo and polysaccharides. They have a one functional group: cetone (C=O) or aldehyde (COH). Pentoses and hexoses can switch from acyciclic to cyclic forms called furanoses and pyranoses.
-Oligosaccharides: small polymer containing between 2 and 10 monoscharides.
-Polysaccharides: big polymers with more than 10 monosaccharides.

These molecules perform numerous roles in living organisms like storage of energy, structural components...

Saccharides yields 4'2 kcal/gr and are abundant in fruits, sweets, honey, beans, tubers, rice, pastas and cerelas. They are a common source of energy in living organisms.

2.Objectives
1-Identify different sugars from its properties.
2-Differentiate mono and disaccharides.
3-Understand the relation between structure and some properties.

3. Materials
-Test tube rack
-10 mL Pipet
-Distilled water
-5 test tubes
-1 dropper
-5 spatula
-Lactose
-Maltose
-Glucose
-Sucrose
-Starch
-Lugol's iodine
-Distilled water

4. Procedure
1- In the first part of the experiment we are going to test some physical properties of the saccharides you have in the lab : flavour, crystal structures and colour. How?
a) Flavour: Put a small amount of each saccharide in your hand and taste it! Is it sweet or not sweet?
b) Crystals: Observe a small amount of each saccharide on a clock glass under magnification.
c) Colour: white, transparent or creamy.

To test solubility:
2-Clean and dry 5 test tubes and label them "G,M,L,SU,S"
3-Put 5 mL of water in each test tube
4-With the aid of a spatula, put a small amount of each saccharide inside the labelled test tube and test if they are soluble or insoluble.
5-Observe if each saccharide forms a mixture called dissolution or a colloidal suspension.

Lugol's iodine test:
(the test you make to comprove if something contains starch)
6-Finally, add 2 drops of Lugol's iodine to each test tube and test if the reaction is positive or negative. Lugol's is a solution of elemental iodine (I) and potassium iodine (KI) in water that is use to test a saccharide. The reaction is positive when iodine reacts by turning from yellow to a purple, dark-blue/black colour.

Finally we are going to test if some foods contain starch. Try with potato!
1-Add 2 or 3 drops of Lugol's solution to one piece of potato and observe whats is happening.

5. Questions
1-Write the empirical formula of each saccharide that you have use. Classify each one in mono,oligo or polisaccharide.
2-Wich are aldoses and wich are cetoses?

Glucose: C6H12O6 monosaccharid (aldo)
Maltose: C12H22O11 disaccharid (aldo)
Sucrose: C12H22O11 disaccharid (ceto)
Lactose: C12H22O11+H2O disaccharid (aldo)
Starch: C6H12O5 polisaccharid (aldo)

3-Wich of the bond links monosaccharides? Oliglicosidic
4-Wich saccharide/s is/are sweet? Is this property related to the structure of the molecule?
Starch is the only one that isn't sweet, because it is polysaccharide.
5-Wich saccharide/s is /are insoluble?  Is this property related to the structure of the molecule?
Starch isn't soluble because it is a very big molecule with high weight
6-Qich saccharide has reacted with Lugol's iodine solution? Starch
7-Wich kind of food contains starch? Flawr, cereals, pasta, rice...
8- Calculate the energy from the nutrition facts label from a cereal:
a)Calculate the energy that comes from the saccharides.
23g saccharides · 4'2 kcal/gr = 96,6 kcal
b)Wich % of the total energy comes from the saccharides?

L4. PH

1.Introduction
The ph is a measure of the acidity or basity of a solution. Solutions with a pH less than 7 are to be acidic and solutions with a pH greater than 7 are basic or alkaline.
Pure water has a pH close to 7, neutral.
The pH is defined as the following equation;
pH= -log(H·)
For mesuring the pH of a solution at the lab we have different pH indicators:
- Universal indicador paper: It's an absorbent paper that has been impregnated with universal indicator. This method consists as a continuous color change from about pH 2 to pH 10.
- pH-meter: Is an electronic device used for measuring the exact pH of a solution. It consists of a glass electrode meter the measures and displays de pH reading.

2.Material

- Distilled water

- Milk

- Wine

- Lemon

- Tomato

- Coffe

- Carbonated beverage

- 10% NAOH solution 

- 10% HCl solution 

- NH3 solution

- Soap solution

- Universal indicator paper (strips)

- pH-meter

- Acetic acid

- Tongs
- 8 X 100 mL Beaker
- 5 test tubes
- Test tubes rack
- 10 mL pipel
- Funnel
- Graduated cylinder

3. Procedure

First of all, we took three beakers and three glasses clock. 

Squeeze the lemon and tomato and put ens their respective beakers. 
We took a piece of indicator paper and put it in the solution for 20 seconds. when removing the strip we saw that each had a different color. I compared it with a flag color according to the color and had a basic or acid concentration. After of all, we squeeze the rest of the lemon inside a beaker and filter the solution with a funnel and cellulose paper.

 













4. Results and observations

The test tube with the highest concentration has a higher acidity wich has less concentracion

L3. OSMOSIS

1.Introduction
Osmosis is the spontaneous movement of solvent molecules trough a semipermeable membrane into a region of higher solute concentration (hypertonic), in the direction that tends to equialize the solute concentrations on the two sides.

When a cell is submerged in water, the water molecules pass trough the cell membrane from an area of low solute concentration to a high solute concentration.

PLASMOLYSIS: When the extracellular concentration is hypertonic and the water moves out of the cell so this cell becomes flaccid.

TURGID: When the extracellular concentration is hypotinc so the water moves inside the cell.

2.Objectives
1-Know about the osmosis phenomena.
2-Understand the osmosis in plasmatic membranes.

3. Hyphotesis
The concentration of salt inside the egg is higher that outside so, the egg will absorve the distilled water trough the semipermeable membrane and the egg will become turgid.

4. Materials
-Egg
-Potato
-Salt
-Distilled water
-Acetic acid (or vinegar)
-Spatula
-600 mL Beaker
-3 clock glass
-Pen
-Spoon
-Knife


5. Procedure
The egg experiment will be divided in two diferent days.
1st day:
Before we start the osmosis experiment we must remove the egg's hard outer shell. So we will star by:
1-Taking a 600 mL beaker and putting the egg inside of it.
2- Then we will cover the egg with vinegar and make note of what's happening.
 Once the egg's shell is removed and the egg is rinsed dry and clean, we will measure and weigh the egg. After that we have to record the dimensions of each egg in a table.
3- Now, we will clean the beaker and put the egg inside again.
4- We cover it with distilled water, and take notes of the volume of solution inside the beaker.

2nd day:
5- After we have left for about a day the egg in the distilled water, we remove the egg using a spoon.
6- We mesure again the dimensions and recod its weight.
7-Making note of the solution volume in the beaker we look if there has been any difference.
8-We observe the results and write the conclusions in our lab worksheet.

Potato experiment
1-Lay out three watch glass
2-Slice the potato in three parts lenghtwise. Each slice must be of 1,5 cm thick.
3-Place each slice onto a watch glass and make a hole in the middle of each slice, but it's important that the hole don't cross the slice.
4-In the first slice hole, don't put anything. The second one fill it with salt and the third with water.
5-Left the preparation 30 min and make note of whats happening.

6. Conclusions
The egg has suffered turgidity.
The potato fulled with water has been inflated, so it has suffered turgidity. The salted potato has wrinkled, it has suffered plasmolysis.

7. Questions
Egg esperiment:
1-What is happening when the shells are soaking of acetic acid?
You can see bubbles that are produced from CO2
2-Write the results of the dimensions and weigh of the egg before and after immersing it in distilled water. Write and draw a simple diagram of the water direction.

Potato experiment:
3-Explain the results of this experiment.
The control potato that has nothing inside the holl keeps normal, without change.
The potato with salt inside the hole becamed fulled of water
The potato with destilled water has becomed turgid, because it has absorved the water completely.
4-Why have we left the first slice without any treatment? (salt or distilled water)
To have a control potato to compare with the other ones and see the results.
5-Which are the dependent and independent variables?
Dependent: the turgency and the potato
Independent: The salt and distilled water, because that are the ones that we have to modify.


General questions:

6-How can you explain (through osmosis) the ability of plant roots to draw water from the soil?
Inside the cells of the plants there are salts and when you put the plants inside water, the cells are more concentrated so the water goes to the roots.
7-What will happen if a saltwater fish is placed in a freshwater (low concentration of salts) aquarium? It will die because of the difference of concentrations.
8-Look at the image and explain what is happening to the erythrocytes: