L8: SAPONIFICATION

L8: Saponification

1. Introduction

Saponification is a reaction with a fatty acid with a strong base resulting in a salt of fatty acid soap is called.

This reaction is very important because the fatty acid are insoluble in water, but the soap molecule form micelles which make colloidal dispersions are believed.

2. Objectives

Our goal with our practice is to create a bar of soap.

3. Material

• 2 beakers of 250 mL
• watch galss
• spatula
• stirring rod
• caustic sosa
• water
• oil
• balance

4.Procedure

First of all, we have taken a 250 ml beaker and we put 90 mL of water, we put another beaker 270 mL of oil on a watch glass we put 32 grams of caustic soda.

We put the water i caustic soda and we mixed with a crowbar and we saw that was exothermic. Then we added the oil and we have mazclado until it has been a little more solid. In addition we have added an aroma.

(paula's blog)

5. Observations

We observed as the mixture of oil, water and caustic soda, has obtained a more solid form.

6. Conclusions

With the mix that we miss, we get soap and let it stand to harden i take shape.

L7: LIPIDS PROPERTIES

L7: Lipids properties

1. Introduction

Lipids are a heterogeneous group of compounds synthesized by organisms that are present in all biological tissues.

Like carbohydrates C,H and O are the principal elements of lipids althought oxygen content is much reduced.

 Lipids are made in general of long chains of hydrocarbons with realtively little oxygen. As a reault os this, they don't dissolve in polar solvents such as water.

In this experiment we are going to test solubility of different oils and how to identify lipids from a sample.

2. Objectives

• Test the solubility of lipids.
• Identify lipids in liquids compounds.
• Understand what are an emulsion and the effects of detergents.

3. Hypotesis

The hypothesis is to differentiate the reaction of water with different solutions.

4. Material

• test tube rack
• 250mL beaker
• water
• 6 test tubes
• cellulose paper
• dropper
• scissors
• glass road

• Olive oil
• soap
• milk with different fat content
• petroleum ether
• ethanol
• sudan III

5. Procedure

Solubility of some lipids:

First of all, we took 3 tubes test and we labeled them to differentiate which would have water, ethanol and ether. Each test tube we added 3 drops of oleic acid, then we put 1 mL of water, ethanol or ether according to the test tube.

Lipids identification:

       -  Translucent mark:

We caught two pieces of cellulose paper and we put a drop of water in one and on the other a drop of olive oil.

        - Sudan III dye:

We have prepared three test tubes with milk plus test water tube with the previous year, each test tube with a different milk (whole, semi-skimmed and without lactose), and we've put a drop of sweat III.

Permanent emulsion:

We put 100 mL of water in a 250 mL beaker. We have put 2mL oil and we have mixed. When we saw what was happening, we have put a few drops of soap and have seen the change.

6. Observations

In the first part we have seen that oil is insoluble in water. When ethanol is in contact with oil, it from micelles and ether can dissolve oil.

In the second part we have identifed the oil from a drop on a cellulose paper.

In the thord part we have tried to identify lipids with sudan III dye. Unfortunately this part of experiment didn't work.

In the fourth part we wanted to see how soh oil. When we added oil to water, it forned a monolayer in the sufare. When we added soap, molecules of oil are dispersed throughout the solution.

7. Conclusion

We can conclude that:

1. Oil is soluble in organic compounds like ether and insoluble in water.
2. Sudan III stairs lipids.
3. Lipids leave a translucent spot in cellulose paper.
4. When soap is added in a water and oil mixture, the soap molecules disperse oil throught the solution (permanent emulsion).

8. Questions

1. From your observation, which compounds can dissolve lipids?

The ether can dissolve the 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?

The oil is not soluble in water and remains in the top of the solution.

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

Because the oil has a melting point much lower melting, since the chain C is smaller.

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

because it is greasy, contains lipids.

5. Which type of milk contains more lipids? why?

Whole milk because it contains all lipids having milk.

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

It produces a permanent ebulltion.

7. What did the soap do to the fat?

That can not join again.

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

L6: Fehling's test: reducing sugars

1. Introduction

Fehling solution is a chemical test used to differentiate between reducing and non-reducing sugars. 

Fehling's reagent has two separate solutions: Felhing A and felhing's B.

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

Felhing's B: clear and colourless solution of potassium sodium tartrate and sodium hydroxide.

Some sugars are capable of reducing copper II ions to copper I ions. This reducing ability is useful in classifying sugars. When the sugar to be tested is added to the Felhing's solution sugars can be oxidized anf felhing'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. Hypotesis

The hypotesis is to identify which sugars perform felhing reactor's.

4. 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

5. Procedure

First of all, we took 5 test tubes from the previous practice and we put 2 mL of Felhin's A and B Feling's solutions and put them to warn up. After 10 minutes we took the test tubes and we observed the results.

6. Observations

We have observed that glucose, maltose, lactose Felhing's reagent changed from blue to orange. And sucurose the mixture with felhing reagent didn't change the same with starch.

7. Conlusions

Monosaccharides  and some disaccharides have reducing power. However polysaccharides like starch isn't reducing sugar.

8. Questions

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

The OH from an anomeric C.

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

If we hydrolize starch, glucose are released and they react with Felhing reagent.

3. Would have you obtained a Felhing's positive test if you had hydrolyzed the sucrose (as you have done with starch)? why?

The sucrose has no free 0H therefore not react with the reagent Felhing, like the starch.

4.  What does " reducing sugars" term mean?

The solutions that react with the reagent Felhing are monosaccharides having a free OH, such as glucose, fructose, sucrose and maltose.

L5: SACCHARIDES PROPERTIES

L5: Saccharides properties

1. Introduction

Saccharides are organic molecules consisting of C, H and O atoms. The empirical formula is CnH2nOn.

The groups are:

• Monosaccharides: formed by a linear carbon chain, are the building blocks of oligo and polysaccharides. They have a one functional group: centone or aldehyde.

• Oligosaccharides: small plymer containing between 2 and 10 monosacharides.

• Polysaccharides: big polymers with more than 10 monosaccharides.

Saccharides yield 4,2Kcal/gr and are abundant in fruits, sweets, honey, beans, tubers, rice, pastas and cereals.


2. Objectives

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

3. Hypotesis

The hypotesis is to differentiate the disaccharides and polysaccharides with their properties.

4. Material

• Test tube rack
• 10ml Pipet
• Distilled water
• 5 test tubes
• 1 dropper
• 5 spatula

• Lactose
• Maltose
• Glucose
• Sucrose
• Starch
• Lugol's iodine
• Distilled water

5. Procedure

First of all, we took 5 test tubes and test tube rack and one mark each test tube with the initial if it was lactose, maltose, glucose, sucrose ans starch. 

when we had all the saccharides in the corresponding test tube look if you had the properties of saccharides: flavor (sweet / not sweet), crystalline form, color (white / cream). 

when we saw these properties, we put 5ml of water in each test tube, to see the property of solubility (soluble / insoluble) using 10ml pipet. 

Then we took the Lugol's iodone and put a drop in house test tube with dropper. The test tube that was put Canvio dark color, I wanted to say was polysaccharides. In this case it was the starch.

6. Observations

Thanks to the properties of saccharides we could see that the starch was not a disaccharides is a polysaccharides, as it was the only one that had colored cream, was not soluble and with Lugol's iodine test was positive.

7.Conclusions

Lactose, maltose, glucose, and sucrose are disaccharides that meet these properties, while the starch is polysaccharides.

8. Questions


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

(CnH2nOn)^N - String name

C6H12O6 = glucose - monosaccharides
C12H22O12 = maltose - disaccharides
C12H22O11 = sucrose - disaccharides
C12H22O11 = lactose - disaccharides

starch - polysaccharides

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

glucose - aldoses
maltose - aldoses
sucurose - ketoses
lactose - aldoses
starch - aldoses

3. Which bond links monosaccharides?

o-glicosidic

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

All saccharides aren't sweet, except the starch that is sweet.

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

Starch because is a very big molecule and it have a molecular weight high.

6. Which saccharide has reacted with lugol's iode solution?

Starch

7. Which kind of foods contain starch?

fluor, cereals, rice..

8. Calculate the energy from the nutrition facts label from a cereal:

a) Calculate the energy that comes from the saccharides.

23gr saccharides ------ 4,2gr · 23 gr = 96,6 kcal

b) Which % of the total energy comes from the saccharides?

L4: PH

L4: PH

1. Introduction

The ph is a measure of the acidity or basicity of a solution. Solutions with a PH less than 7 are said to be acidic and solutions with a PH greater than 7 are basic. AAnd the solution that have a pH 7 are neutral.

Equation for following PH:                 pH= -log (H+)

For mesuring the PH of a solution at the lab we have different pH indicators:

- Universal indicator paper: this method consists as a continous colour change from about pH 2 to pH 10.

- pH- meter: It consists of a glass electrode connected to an electronic meter that measures and displays the pH reading.

2. Objectives

•  Measure different pH values of organic and inorganic solutions.

•  Prove different methods of measuring pH

3. Hypothesis

If the solutions are more big than 7, it will be a basic concentration and if the solutions are more little than 7, it will be acidic concentration.

4. Material

• Distilled water
• Milk
• Wine:  red or white
• Lemon
• Tomato
• Coffee
• Carbonated beverage
• 10% NaOH solution
• 10% HCL solution
• NH3 solution
• Soap solution

• Universal indicator paper (strips)
• pH-meter
• Acetic Acid
• Tongs
• 8x100 ml Beakers
• 2 clock glass
• 1x250 ml Beaker
• 5 test tube rack
• 10 ml Pipet
• funnel
• graduated cylinder

5. Process

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.

We prepared a test tub rack with 5 test tubes cleaned with distiller water. We marked the tubis with the labels: A, A1,A2,A3, and B.

We added 10 ml of lemon juicxe to tubes A and B and took the A tube and put 5ml of its lemon juice to test tube A1. Took the A1 tube and put 2,5ml of its lemon juice to tube A2 and the A2 we took it and put 1,2ml of its lemonjuice to tube A3.
We added distilled water to each test tube until it has the same volume as test tube B (10ml).

We calculated the concentration of each test tube with the formula we have below:

               Concentration (%) = (volume of juice / total volume) · 100

6. Observations

We observe that our hypothesis had been proven since the solutions of the strips out of the correct color, according to its degree of acidity or whether it was more basic.

• Acidic concentration: HCl(pH=1) , vinegar(pH=3) , wine white(pH=3) , tomato(pH=4), coffe(pH=6), milk(pH=6).

• Neutral concentration: ditillated water (pH=7)

• Basic concentration: soap(pH=10), NaOH(pH=14)

7. Conclusions

My conclusion is that the hypothesis has been confirmed, since the solutions have come out with the proper pH.

8. Questions

Which of the solutions gave and acid pH?

Acidic concentration: HCL(pH=1) , vinegar(pH=3) , wine white(pH=3) , tomato(pH=4), coffe(pH=6), milk(pH=6).

Which of the solutions was alkaline?

Basic concentration: soap(pH=10), NaOH(pH=14)

Which of the solutions were neutral? Did you expect these results? Explain.

Neutral concentration: ditillated water (pH=7)

Yes, i did. Because the distillated water we used to clean the concentrations that we remaining neutral.

How does a pH of 3 differ from pH of 4 in terms of H+ comcentrations?

Concentration becomes more basic.

In the second part of the experiments, you have compared the pH of the same product in different comcentrations, In this case explain:

                       a) Which is the dependent variable?

                        concentration can't vary alone.

                        

                       b) Which is the independent variable?

                          concentration can vary alone.

                       c) Which is the problem that we want to solve?

                          we equalize the concentrations

                       d) Which is the control of the experiment?

                         The control is the tube B

                       e) Write the results and conclusions of your experiments

                          

                         At finally concentrations of lemon and distilled water are matched.

 Which pH do you think that gastric juices might have? why? Do you think that intestinal pH has the same pH? why?

Has an acid pH, as it serves to digest the food you eat and to digest. 

Yes, because all are.

 Which Ph do you think that blood might have? why?

Neutre concentration, because it would have red blood hypotonic or hypertonic media and the globule is deformed or inflate to match the concentrations.

 What is acid rain? which are the consequences in the ecosystems and how is its formation pattern? is rain in Barcelona acid or alkaline?

Acid rain is formed when moisture in the air combines with nitrogen oxides, sulfur dioxide and sulfur trioxide emitted by factories, power plants, boilers and vehicles that burn coal or petroleum products containing sulfur. In interaction with the rainwater, these gases are nitric acid, sulfuric acid and sulfurous acid. Finally, these chemicals fall to the ground accompanying the precipitation, forming acid rain.

Is alkaline.

L3: OSMOSIS

L3: OSMOSIS


1. Introduction

Osmosis is the spontaneous movement of solvent molecules through a semipermeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. 

When the extracellular concentration is hypertonic, water moves out of the cell and the cell becomes flaccid: plasmolysis.
When the extracellular concentration is hypotonic, water moves inside the cell and it becomes turgid.


2. Objectives

• Know about the osmosis phenomena.
• Understand the process of osmosis in plasmatic membranes. 

3. Hypothesis

The hypothesis is that in the experiments with an egg and a potato, the osmosis going to happen from the plasmolysis and turgid. 

4. Material

• Egg
  
• Potato
  
• Salt
  
• Distilled water
  
• Acetic acid (or vinegar)
  
• Spatula
  
• 600 mL Beaker
  
• 3 Clock glass
  
• Pen
  
• Spoon
  
• Knife 
  

5. Procedure

EGG

First of all, we took a beaker of 600 ml and then, we put the acetic acid and egg into the beaker. After that, not only did we removed it with a spoon but, we covered it as well.

Now, we'll let the beaker rest some days and then, we'll look if the egg has grown  by the turgid process. Some days later, the egg was bigger so we put salt to look if the egg was going to do the plasmolysis process and it was like we thought.

Grams per egg:

1) Normal egg: 188,1gr

2) Turgid : 209gr

3) Plasmolysis: 192 gr

POTATO

Fist of all, we took a potato and then, we cut on three pieces and we did a whole in the middle of every single piece of potato.

We didn't put anything on the first piece because it was the proof one.

On the second piece, we put salt in the whole and theoretically was going to do the plasmolysis process.

On the third piece, we put distilled water in the whole and theoretically was going to do the turgid process and it was like we thought.

6.Observations

In two experiments we have observed that our hypothesis was true.

7.Conclusions

On one hand, if we put salt in some aliment, the concentration of salt will be bigger out. In consequence of that, water will apear by the plasmolysis process. On the other hand if we put a distilled water the concentration will be bigger out. In consequence of that, water will disappear by the turgid process.

8.Questions 

Egg experiment:

1. What is happening when the shells are soaking of acetic acid?
   
   The acid acetic disolt the shells.
   
   
2. Write the results of de dimensions and weigh of the egg before and after immersing it in distilled water. Write and draw a simple diagram of the water direction.
   
   
   1) Normal egg: 188,1gr
   2) Turgid : 209gr
   
   
   3) Plasmolysis: 192 gr
   
   

Potato experiment:

3. Explain the results of this experiment.
   
   On one hand, if we put salt in some aliment, the concentration of salt will be bigger out. In consequence of that, water will apear by the plasmolysis process. On the other hand if we put a distilled water the concentration will be bigger out. In consequence of that, water will disappear by the turgid process.
   
   
4. Why have we left the first slice without any treatment (salt or distilled water)?
   
   To compare all the other proofs.
   
   
5. Which are the dependent and independent variables?
   
   The dependent variable is that you modificable and the independent variable is that change alone.

General questions:

6. How can you explain (through osmosis) the ability of plan trots to draw water from the soil?
   
   The capilars.
   
   
7. What will it happen if a saltwater fish is placed in a freshwater (low concentration of salts) aquarium?
   The fish would inflate.
   
   
8. Look the image you have below and explain what is happening to the erythrocytes in each situation: 
   
   1. plasmolysis
   
   2. control
   
   3. turgid