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
   

L2: MINERALS SALTS IN ORGANISMS

L2: MINERALS SALTS IN ORGANISMS

1. Introduction

What makes bones strong?

Even though bones are very light, they are also very strong. However, how strong they are depends on how much of the mineral calcium carbonate they contain. 

In this experiment we will make the bones lose their strength and we can bend without any kind of problem.

Bone contains calcium carbonate, when mixed with the acid bones carbon dioxide is removed. 

When we mix the acid with calcium carbonate is removed and this is only the collagen, and this process makes the bones are rigid and strong.


2. Objectives

• Identify mineral sals in organisms
• Understand the function of inorganic biomolecules in skeletal structures of organisms.

3. Hypothesis

The hypothesis is that the bones after a week can break with facilities.

4. Material

• Some molluscs’ shells (clams, mussels, etc.)
• Dried, cleaned chicken or lamb bones
• Water
• Acetic Acid
• Tongs
• 2 x 600 mL Beaker
• Clock glass
• distilled water
• bones

5. Procedure

First, we did carefully cleaned and cut much of the meat away from the chicken thin bone  and then we examined the flexibility of the bone by tried to bend it with our fingers.

We took a beaker and made and acid acetic solution and took the chicken or lamb bones and drop them in the acid acetic solution that we did.

We leave it 24 hours and saw what happened to the bone. we have put a clock glass at the top of the beaker to protect the solution.

After, we removed the bones from the vinegar with a tong and we left it soak with water.


6. Observations

One week later, we saw the bones and we tried to broken them, but we only broke the little bones, and the big bones we couldn't.

7.Conclusions

My conclusion is that the experimence is feasible but if we would have left two days more, the big bones have broken and the hypothesis would be true. 


8. Questions

1. Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.

CH3COOH + CACO3

2. What is happening when the shells are soaking of acetic acid? What are the bubbles that you can see?

Releasing this CO3

3. What is happening to the bone after some days of soaking it in acetic acid? Why is the bone flexible now?

Realising the CO3 and the bone is stiffness.

4. So, what is the function of the calcium carbonate in the skeletal structures?

The stiffness.

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 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?

more later, corals reefs will dissapear because it's do to calcium carbonate and te Co2 sometime increases more.