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.