Introduction:
Event 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.
When calcium carbonate and acetic acid combine, a chemical reaction takes place and carbon dioxide is released:
CH3COOH + CaCO3 -> CO2 +
Bones are made also of soft material, collagen. When bones are placed in the glass with acetic acid, this acetic dissolve the calcium carbonate so that only collagen is left. Collagen gives the bones strength and rigidity.
The objectives of the experiments are:
- Identify mineral salts in organisms.
- Understand the function of inorganic biomolecules in skeletal structures of organisms.
- Identify mineral salts in organisms.
- Understand the function of inorganic biomolecules in skeletal structures of organisms.
Materials:
- Shells
- Chicken bones
- Distelled water
- Acetic acid
- Beaker (250 mL)
- Clock glass
- Chicken bones
- Distelled water
- Acetic acid
- Beaker (250 mL)
- Clock glass
Procedure:
Chicken bones:
- Clean and cut the meat away from the chicken bone
- Examine the flexibility of the bone by trying to bend it.
- Take a beaker and add vinegar.
- Take the chicken bones and drop them in the acid acetic solution (vinegar)
- Leave it 48 hours or maybe 72 hours and see what happens to the bone. Put a clock glass at the top of yhe beaker to preotect the solution.
- Examine the flexibility of the bone by trying to bend it.
- Take a beaker and add vinegar.
- Take the chicken bones and drop them in the acid acetic solution (vinegar)
- Leave it 48 hours or maybe 72 hours and see what happens to the bone. Put a clock glass at the top of yhe beaker to preotect the solution.
Shells:
- Take another beaker and make the same acid acetic pure solution with distilled water.
- Put inside some shells and make note of what is happening.
- Put inside some shells and make note of what is happening.
Results:
Conclusions:
Questions:
1- Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.
CH3COOH + CaCO3 -> CO2 +
2- What is happening when the shells are soaking of acetic acid? What are the bubbles that you can see?
Despren CO2 i bombolles
3- What is happening to the bone after some days of soaking it in acetic acid? Why is thw bone flexible now?
L'os és més flexible després d'uns dies ja que nomes queda el collagen.
4- So what is the function of the calcium carbonate in the skeletal structures?
Rigility
5- Increases in carbon dioxide to the atmosphere from burning fossil fuels and deforestation threaten to change the chemistry of the seas. Evidence suggests that this increase in atnospheric carbon dioxide is lowering the pH of the oceans in a process called ocean acidification. How can adification affects corals reefs?
A la llarga els coralls desaparareixeran ja que estan fets de carbonat calcic i el CO2 cada cop augmenta mes.
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| Egg shell with vinegar |
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| shell with vinegarr |
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| egg shell dissolt with vinegar |
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| bone with vinegar |
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