pH

Introduction: 
The pH is a measure of the acidity or basicity of  a solution. Solutions with a pH les 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.
Equation: pH= -log(H+)
We have different measure indicatiors of pH


Material:

-Distiled Water
-Milk
-Wine
-Lemon
-Tomato
-Carbonated beverage
-Carbonated beverage
-NaOH solution
-HCl solution
-NH3 solution
-Soap solution
-Universal indicator
-Acetic Acid
-Tongs
-Beakers 8 x 100ml and 1 x 250ml
-2 clock glass
-5 test tubes
-Test tube rack
-10ml pipet
-Funnel
-Graduated Cylinder


Objectives: 

1. Mesure different pH values of organic and inorganic solutions
2. Prove different methods of measuring pH

Procedure: 
We put the solutions in different beakers of 250. Squeeze the lemon and tomato in two clock glasses and mesure the pH. Later, we take the indicator paper and put into the beakers than have a solution and mesure the pH and compare with the others solutions the colour. (acidic, neutral, alkalin). When we have all the results, in the blackboard, we put the pH of all the solutions and we compare with the others grups of students.

Observations: 
The results of the other grups are very similated than ours and it's mean that our results of pH are good.
The pH of NaOH is 14 but in the indicator paper the maxim is 12. 
The pH of distiled water are 7, the answer of grups 3 and 4 are wrong.

2nd PART

How does concentration affect pH?

We squeeze the rest of the lemon inside a beaker and filter the solution with and cellulose paper. 

Prepare a test tub rack with 5 test tubes. We mark the tubes with letters (B, A, A1, A2, A3). 

In the tub B we put 10 ml of lemon juice. (0ml of distilated water)

In A 5ml (5ml of distilated water)

In A1 2,5ml (7,5ml distilated water)

In A2 1,3ml (8,7ml distilated water)

In A3 1,3ml (8,7ml distilated water)

pH of the tubs

A1--> 2,81 

A2--> 3,08

A3--> 3,08

A--> 2,71

B--> 2,77

QUESTIONS

1. Lemon, tomato, vinegar, coke, HCl and wine

2. NaOH and soap solution

3. Were neutral the milk, H2Od and soy milk. I spect that results in the majority but I thought the milk was alkaline before the experiment.

4. The pH 3 have more H+ than the pH. Have ten times more H+.

5. 
a) The pH i the dependent variable
b) The lemon juice concentration in the independent variable
c) Can lemon juice concentration variate the PH?
d) The test tube B, is the control of the experiment, have 100% lemon juice.
e) (No puc copiar el excel en el blog, estic intentant solucionar)















6. They have to have acid pH because their function is descomponate the aliment that you eat.

7. The blood I think that is neutral. Because if the blood is acid, the mecanism of our organism actuate to compensate and create an imbalance.

8. Is a broad term referring to a mixture of wet and dry deposition from the atmosphere containing higher than normal amounts of nitric and sulfuric acids. Acid rain causes acidification of lakes and streams and contributes to the damage of trees at high elevations. Many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings. 
The rain in Barcelona is acid.

Osmosis

Osmosis 

Introduction: 

Is the spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides. 
Water molecules travl through the plasma membrane in order to equilibrate the intra and extra cellular concentrations.

Material:
- Potato
- Spatula
- Salt
- Distilled water
- Acetic acid
- Knife
- 600 mL Beaker
- Pen

Objectives: 

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

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

Observations: 
In the first potato (control of the experiment) is the normal potato.
In the second pass (salt treatment) the potato has more water than the beginning.
In the third pass (distilled water) the potato absorbs all the water and now it's hard and dry.

Mineral Salts in Organisms

Introduction: 

- In this experiment we work with bones and shells. The bones are very hard and their hardness depends on the amount of calcium carbonate (CaCO3 ) in them . What we do in this experiment is that the bone are more flexiblity. And the same with the shells.

Materials:

- Some mollusk shells (clambs, ...)
- Dry cleaned chicken or lamb bones
- Water
- Acetic acid
- Tweezers
- 2 x 600 ml Glass
- Crystal Clock

Objectives:

1. Identify minerals salts in organisms.
2. Understand the function of inorganic biomolecules in skeletal structures of organisms.

Procedure: 

Bones:

- Separate the chicken-bone and clean it carefully.

- Examine the flexibility of the bone.

- Take a beaker and put the acid acetic solution or add vinegar (400mL) and water (200mL) inside of it. Later we put the bone inside the beaker.

- 24 hours later we returned to see the results of the bone.

Observations of bones: 

The bone is more flexible because it is contact with the acetic acid and the vinegar, and lose his hardness.

Shells: 
- Took a different beaker and put water and calcium carbonate.
-Inside the beaker put the shells that the teacher gave us.


Obervations of the shells: 
-In the change of class we observed that the shells were smaller and had holes.
-Later, we saw a lot of bubbles in the beaker.
 


QUESTIONS: 
1. Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.
    Bubbles
2. What is happening the shells are soaking of acetic acid? What are the bubbles you can see?
    The bubbles are 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 calium carbonate in the skeletal structures?
    Rigidity.
5. Increases in carbon dioxide to the atmosphere from the burning fossil and deforestation threaten to change the chemistry of the seas. Evidence suggests that this increase in atmospheric carbon dioxide is lowering the pH of the oceans in a process called ocean acidification. How can acidification affects corals reefs?
    The reefs coral will be dissolve because the pH will be reduce of the corals.