L8: SAPONIFICATION

1. INTRODUCTION

Saponification is a reaction of a fatty acid with a strong base. This reaction forms a salt called soap.

2. OBJECTIVES

- To create a soap.


3. MATERIAL

-2 beakers of 250 mL
-Watch galss
-Spatula
-Stirring rod
-Sosa
-Water
-Oil
-Balance

4.PROCEDURE

First,we have taken a 250 ml beaker and we put 90 mL of water. We put another beaker with 270 mL of oil, and on a watch glass we have mesured 32 grams of sosa. We put the sodium hydroxide into the water  and mixed ( we have tested wich kind of reaction takesplace). Then put the oil very slowly and removed.

5.OBSERVATIONS

We can obtain the soap.

L7: LIPIDS PROPERTIES

1. INTRODUCTION

Lipids are heterogeneous group of compounds synthesized by organisms, that are present in all biological tissues. These compounds are characterized as natural substances that do not mix with water but dissolve in organic solvents, There are several classes of lipids including: fatty acids,waxes,tryacyglycerols, phospholipids,terpens and steroids. C,H and O are the principal elements of lipids althought oxygen content is reduced. Lipids are made in general of long chains of hydrocarbons with relatively little oxygen, they tend to be non-polar, meaning they do not dissolve in polar solvents such as water.


2. OBJECTIVES

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


3. MATERIAL

- Test tube rack
- 250ml beaker
- Water
- 6 test tubes
- Cellulose paper
- Dropper
- Scissors
- Glass rod
- Olive oil
- Soap (detergent)
- Milk with different fat content
- Petroleum ether
- Ethanol
- Sudan III

4, PROCEDUCE 

- Solubility of some lipids:

1. Clean and dry three test tubes. Label as W (water), ethanol (E), and PE (ether).
2, Add 3 drops of oleic acid to 3 small test tubes.
3. Add 1ml of water in the first test tube (W).
4. Add 1ml of ethanol in the second test tube (E).
5. Add 1ml of petroleum ether in the third test tube (PE)
6. Shake carefully each test tube and record solubility and observations in my worksheet.

- Lipids identificaion:

A) Translucent mark

1. Cut two pieces (10X10cm) of cellulose paper.
2. Put 1 drop of water in the first squared piece. You will see a translucednt spot. Wait for a while and observe what is happening,
3. Put 1 drop of olive oil in the second squared piece of cellulose paper. You will see a translucent spot,

B) Sudan III dye: Be careful red can stain clothes!!!

1, Take the W test tube of the first experiment and add 2 drops of Sudan III.
2. Prepare four test tubes: 3 with different fat content (M1, M2, M3) and soda (S). Add two drops of sudan III and observe the results.

- Pemanent emulsion:

1. Take a 250ml beaker and put 100 ml of water.
2. Add 1ml of olive oil. With a glass rod stir the mixture vigorously and let it stand a few minutes.
3. Make note of what is happening,
4. Add 2 drops of soap and stir the mixture again. Let it stand for a few minutes and notice the diferences between both mixtures,

5. OBSERVATION

 We have been able to observe...

- In the first experiment we have tested that oil is insoluble in water and soluble in ether. In the second test tube the oil and ethanol didn't mix, the oil formed micelles.

- In the second experiment we tried to stain lipids with sudan III, unfortunatelly the dye didn't stain.

- In the last eperiment we tested that soap forms little micelles with oil, in a water solution. This mixture is called permanent emulsion.


6. 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.

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

Because it contains lipids.

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

Whole 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't 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

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. PROCEDUCE

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.

5.RESULTS OR OBSERVATIONS

 

6. 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 molecules that react with the reagent are Felhing having a free OH.

2.  Compare the results you obtained for the fehling's test of starch and fehling's test of hydrolyzed starch. Explain your results.
The starch is blue,because it react with lugol's iodine.

3. Would have you obtained a Felhing's positive test if you had hydrolyzed the sucrose ? Why?The sucrose has no free 0H.

4. What does " reducing sugars" term mean?
Reducis the one that reacts positive to the Fehling's test. Because have a free OH.

P4: PH

P4. 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. PROCEDUCE

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 OR OBSERVATIONS

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

 

L3. OSMOSIS

L3: Osmosis

1. INTRODUCTION

Osmosis in the spontaneous movement of solvent molecules trough a semipermeable membrane into a region of higher solute concentracion in the direction that tends to equalize the solute concentracions on two sides. Osmosis is a vital process in biogical systems, as biogical membranes are semipermeable. Water molecules travel trhoug the plasma membrane in order to equilibrate the intra and extra cellular concentracions. When a cell is submerged in water, the water molecules pass trough the cell membrane from an area of low solute concentracion to high solute concentracion. When the extracellular concentracion is hypertonic, water moves out of the cell and the cell becomes flaccid; plasmolysis.

When the extracellular concentracion is hypotonic, water moves inside the cell and it becomes; turgid.

2. OBJECTIVES

- Know about the osmosis phenomena.

- Understand the process of osmosis is plasmatic membranes.

3. MATERIAL

- Egg

- Potato

- Salt

- Distilled water

- Acetic acid

- Spatula

- 600 mL Beacker

- 3 Clock glass

- Pen

- Spoon

- Knife

4. PROCEDURE

EGG: This experiment will be divided in two days,

Under the hard outer shell of a chicken egg is a semipermeable membrane that allows air in moisture to pass though. Becaue water membrane can move into and out of the egg but larger molecules cannot, the semipermeable egg membrane allows for an exploration of concepts of diffusion and osmosis.

1 Day: 

1. Take a 600 mL beaker and put inside the egg

2. Cover the egg with vinegrar and make note of what's happening. 

* Once the egg's shell is removed and the egg is rinsed dry and clean, measure and weigh the egg. Record the dimensions of each egg in a table.

3. Clean the beaker and put the egg inside again.

4. Cover in with distilled water. Make note of the volume of solution inside the beaker.

2 Day: 

5. Left the egg one day in the distilled water. After about a day, carefully remove the egg using a spoon.

6. Measure again the dimensions and record is weight.

7. Make note of the solution volume in the and notice if there has been any difference.

8. Observe the results and write your lab workksheet.

POTATO:

1. Lay out three watch glass.

2. Slice the potato in three parts lenghwise. Each slice must be of 1,5cm thick.

3. Place each slice onto a watch glass and make a hole in the middle of each slice.

4. In the first slice hole, don't put anything. The second fill it with salt and the third with distilled water.

5. Left this preparation 30 minutes and make note of is happening.

5. RESULTS OR OBSERVATIONS

The egg we have observated that when we put the egg with acetic acid the shell what was covering the egg. The egg with the pass of the days it becomes viscous. At the end, the dimension of the egg increased for the hypotonic concentration. The last experiment that we made with potatoes, we thought that in the firs slice,  there would be no reaction. In the second one, with salt the potato will be flaccid, because the water inside will go out because the potato is a hypotonic and the salt is a hypertonic and the potato with distilled water, it becomes turgid. In this case the potato it's a hypertonic and the water hypotonic, and the last potato with distilled water, it becomes turgid. I

L2: MINERAL SALTS IN ORGANICS

L2: MINERAL SALTS IN ORGANICS

1. INTRODUCTION

Even though bones are very light, they also very strong. However, how strong they depends on how much of the mineral calcium carbonate they contain. Eggs and bones contain calcium carbonate, when calcium carbonate and acetic acid combine, a chemical reaction takes place and carbon dioxide is realised. This effect we observation becouse are some bubbles in solution, 

When bones are placed in the glass with acetic acid, the acid dissolve the calcium carbonate so that only collagen left. During foetal development, strong fibbers of collagen protein form a matrix for bones. The matrix solidifies by a process called calcification.. During this process, calcium phosphate or hydroxyapatite is deposited in the fibbers of collagen and gives the bones strenght and rigitidy.

2. OBJECTIVES

- Identify mineral salts in the organism

- Understand the funtion in organic biomolecules.

3. MATERIAL

- Some molluscs' shells (clams,mussels,etc.)

- Dried, cleaned chicken or lamb bones

- Water

- Acetic acid/ vinegrar

- Tong

- 2 * 600 mL Beaker

- Clock glass

- Destilled water

4.PROCEDURE

Chicken or lamb bones.

Carefully clean and cut ad much of the meat away from the chicken thin bones as possible. Examine the flexibility of the bone trying to bend it with your fingers. Take a beaker and make and acid acetic solution or add vinegrar. Take the chicken or lamb bones and drop them in acid acetic solution that you have made. Leave it 24-48 hours and see what happens to the bone. Remove the bones from the vinegrar with a tong and soak them with water. Annotacion: 

Lamb bone ribs; 18.2

Lamb bone 19

Mollusks shells.

Take another beaker and make the same acid acetic solution, Put inside some shells and make note of what is happening. 

5. RESULTS OR OBSERVATION

One week later we saw the bones are broken. And the mollusks shells disapear.

Welcome to Maria science lab e-notebook

Hello! My name is  Maria Luna, and I student in Centre d'Estudis Prat. This blog i want explain the experiments.
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