L.2 MINERALS SALTS IN ORGANIMS

OBJECTIVES
We want to see how much CaCO3 there is in these bones. 
Identify mineral sals in organism and understand the function of inorganic biomolecules in sketal structures. 

MATERIAL

• Acetic Acid
• Chicken bones
• Mollusc's shells 
• Baker 
• Tongs

PROCEDIMENT
Chicken bones

1. Carefully clean and cut ad much of the meat away from the chicken thin bone as possible.
2. Examine the flexibility of the bone by trying to bend it with your fingers.
3. Take a baker an add vinegar 
4. Take the bones and drop them in the acid acetic solution that you have made.
5. Leave it 24 hours and see what happens to the bone. 
6. Remove the bones from the vinegar with a tong and soak them with water.

Mollusks shells

1. Take another baker and make the same acid acetic solution. 
2. Put inside some shells and make note of what's happening. 

RESULTS

In the case of the bones, the bone is dissolved by calcium salts and just left the conjunctive tissue. The bone is soft, as the salts responsible of the strength of it. 

  

In the case of the shells, the acetic acid dissolves calcium carbonate, so that, the shell loses completely its form. 

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

CaCO₃ (Calcium Carbonate) + CH₃COOH (Acetic from the vinegar) --> Ca (CH₃COO)₂ (calcium acetate)  + H₂O + CO₂

2. What is happening when the shells are soaking of acetic acid? What  are the bubbles that you can see?
Calcium stays in the shells and the Carbon dioxide unpins from it in the way of bubbles.
3. What is happening to the bone after some days of soaking it in acetic acid? Why is the bone flexible now?
Because the Calcium Carbonate has unpinned from the bones and then, collagen , that is soft, has remained in it.  
4. So, what is the function of the calcium carbonate in the skeletal structures.
Calcium Carbonate gives strength and resistance to bones.  
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.

It will happen the same as in the experiment before.