1.4 pH

Introduction
ThepH is a mesure 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 or alkaline. Pure water has a pH close to 7, neutral.
The equation of pH:
pH= -log (H+)


Material
-Destilled water
-Milk
-Lemon
-Tomato
-Coffee
-Carbonated beverage
-10% NaOH solution
-10% HCL solution
-NH3 solution
-Soap solution
-Universal indicador paper
-pH-meter
-Acetic acid
-Tongs
-8·100mL beaker
-2 clock glass
-1·250mL beaker
-5 test tube
-10mL pipet
-Test tube rack
-Funnel
-Graduated cylinder


Objectives
-Measure different pH values of organic and inorganic solutions.
-Prove different methods of measuring pH.


Procedure

To measure the pH of different solutions we are going to put the diferrent solutions in small beakers of 250mL.
1.Squeeze the lemon and tomato in two clock glasses.
2.Take a piece of indivstor paper and place one end of it into the solution. Leave for at least 20 seconds.
3.Remove the indicator paper and compare its colour with the appropiate colour chart.
4.Repeat points 1 to 2 with as many others solutions as you are provided with.
5.Record your results in a result table in your worksheet.


Table of the pH of each of the test tube:

Test	Volume of	Total	Concentration	pH
B	5 + 5	10ml	50	2.2
A1	2.5 + 7.50	10ml	25	2.5
A2	1.3 + 8.7	10ml	15	2.5
A3	1.2 + 8.8	10ml	12	2.6
A	10ml	10ml	1	2.5

Results of the pH with different tubes concentrations:


Our results are wrong bacause we didn't control the volume in each tube.
The pH depends on the proton concentration.
pH= -log (H+)<
We expected that the A test tube (the most concentration) had the lowest pH.


Questions
1.Which of the solutions gave an acid pH?
Lemon, tomato, vinegar, coca.cola, HCl, wine.
2.Which of the solutions was alkaline?
Soop solution, NaOH.
3.Which of the solutions were neutral? Did you expect these results? Explain.
Destilated water and milk. Because it don't have dissolved salts.
4.How does a pH of 3 differ from pH of 4 in terms of H+ concentrations?
In a pH 3 solution there is ten more protons than a solution of pH 4.
5.In the second part of the experiment, you have compared the pH of the same product (lemon juice) in different concentrations. In this case explain:
 a.Which is the dependent variable? Is the Ph.
 b.Which is the indepedent variable?The lemon juice concentraton.
 c.Which is the problem that we want to solve?Can the juice lemon concentration variate the Ph3?
 d.Which is the control of the experiment?Test tube B 100% of lemon juice
 e.Write the results and conclusions of your experiment:It is in a table that is up on the page
6.Which pH do you think that gastric juices might have? Why? Do you think that intestinal pH has the same pH? Why?
It's an acid pH, because it have to undo the food. It is getting basic every tame it get away of the stomach.
7.Which pH do you think that blood might have? Why?
7,2 pH
8.What is acid rain? Which are the consequencies in the ecosystems and how its formation pattern? Is rain in Barcelona acid or alkaline?
The acid rain is a toxic rain, which is formed for the emission of gases from factories.
Somethimes there is acid rain but normaly it is alkaline rain.

1.3 Osmosi

Introduction:
Osmosi is the spontaneous movement of solved molecules through a semipermeable membrane into a region of higher solute concentration (hypertonic), in the direction that tends to equalize the solute concentrations on the two sides. Water molecules travel through the plasma membrane in order to equilibrate the intra and extra cellular concentration.

Material:
-potato
-salt
-distilled water
-spatula
-3 clock glass
-pen
-knife

Objectives:
-Know about the osmosi phenomena.
-Understand the processof osmosi in plasmatic membranes.

Procedure:
Potato
-Cut the potato in three pieces and put one piece in a watch glass, the other piece in another watch glass and the last one in another watch glass.
-We take the spatula and make a small hole in the middleof the potato. In this hole we put salt and another hole, put distilled water.




Observations:
In the potato with the salt, it can be sean more water than the beginning.
And the potato with the distillited water it can be sean the potato absorbs the water and now it's more hard and dry.

1.2 Mineral salts in organisms

Introduction:
In this experiment we worh with bones and shells.
The bones are very light, they are olso very strong, and are depens on how much of mineral calcium carbonated (CaCO3) they contain, and shells with the acetic acid was dissolvented.
What we do in this experiment is that the bone are more flexibility and the shells melt.

Materials:
-shells
-bones
-water
-acetic acid
-tongs
-2 * 600mL beaker
-clock glass
-mineral salts
-safety goggles
-cloridric acid

Objectives
-Identify minerals salts in organisms.
-Understant the function of inorganic biomolecules in skelet structures of organisms.

Procedure:
A) Bones:
1- Carefully clean and cut ad much of the meat away from the chiken thin bone as possible.
2- Examine the flexibility of the bone by trying to bend it with your fingers.
3- Take a beaker and make and acid acetic solution or add vinegar.
4- Take the chicken or lamb bones and drop them in the acid acetic solution thet you have made.
5- Leave it 24 hours and see whats happens to the bone. Put a clock glass at the top of the beaker to protect the solution.
6- Remove the bones fromthe vinegar with a tongs and soak them with water.
7- Write the results in your lab worksheet.



B) Shells:
1- Take another beaker and make the same acid acetic solution.
2- PUt inside some shells and make note of what is happening.
3- Write the observation in your lab worksheet.

Observation of bones
The bone is more flexibility because lose the ridigity with the vinegar, there are now only
collagen.










REACTIONS: HCl + CaCO3 ·········> CO2 +CaCl2

Observation of shells
The shells was dissolveted.



Questions
1-Writethe reaction that takes place when the acid acetic reacys with the calcium carbonate.
Bubbles.
2-What happening when the shells are soaking of acetic acid? What are the bubbles that you can see?
Bubbles was formed, this was carbon dioxide.
3-What is happening to the bone after some days of soaking it in acetic acid? Why is the bone flexible now?
The bone is more flexible.
4-So, what is the function of the calcium carbonated in the skelet structures?
Rigidity.
5-Increases in carbon dioxide to the atmosphere from the burning fossil fuels and deforestation threaten to change the chemistry of the seas. Evidence suggests thet this increases in atmospheric carbone dioxide is lowering the pH of the oceans in a process called ocean acidification. How can acidification affects coral reefs?
The coral reefs will be dissolve.