Copper sulfate is a hydrated crystal with the formula CuSO4*5H20 and a deep blue color. when its heated, the crystals crumble and turn white. (a) propose an explanation for this change of color.
(b) what would you do to restore the blue color?
When heating a crystal of CuSO4.5H2O, the crystal suffers a loss of H2O and leaves a grey colored powder. What might you do to restore the crystal> Place it in a closed vessel with water (in a separate container) and the dry CuSO4 will absorb the water (from the water vapor) it lost when heated and the blue color will return.
a) Well, it seems that copper sulfate is experiencing a serious case of the blues! When the crystals are heated, the water molecules trapped within its structure start to escape. As these water molecules bid farewell, they take away the source of that beautiful deep blue color, leaving behind a pale, colorless residue. So, it's the evaporating water that causes this transformation.
b) To bring back that gorgeous blue hue, one would need to reintroduce water molecules to the equation. You can achieve this by adding a drop or two of water to the crumbled white residue and giving it a gentle mix. Voila! With the reunion of water and copper sulfate, the crystal should regain its vibrant blue shade. Just be careful not to overwater it, or you might end up with a soggy mess!
(a) The change in color of copper sulfate crystals from deep blue to white when heated can be explained by the loss of water molecules from its structure. The formula CuSO4*5H2O indicates that there are five water molecules associated with each copper sulfate molecule. These water molecules are known as water of crystallization or hydrate water, and they are tightly bound within the crystal lattice.
When copper sulfate crystals are heated, the increase in temperature provides enough energy for the water molecules to break free from the crystal lattice. As a result, the hydrated copper sulfate crystals lose their water molecules and become anhydrous copper sulfate (CuSO4) in a powder form. The loss of water molecules leads to a structural change in the crystal, causing the deep blue color to fade away and appear white. This is mainly because the presence of water molecules contributes to the absorption and reflection of light, which gives the crystal its characteristic blue color.
(b) To restore the blue color of anhydrous copper sulfate, you would need to rehydrate the crystals. This can be done by adding water to the powder form of copper sulfate and allowing it to dissolve. As the water molecules reassociate with the copper sulfate, the crystal lattice will reform, resulting in the restoration of the deep blue color.
To perform this rehydration process, you can follow these steps:
1. Take the anhydrous copper sulfate powder and place it in a clean, dry container.
2. Gradually add water to the powder while stirring continuously. Start with small amounts of water and keep adding until the powder is fully immersed and saturated.
3. Continue stirring the mixture until all the anhydrous copper sulfate dissolves completely. This may take some time depending on the amount of powder used.
4. Once dissolved, the rehydrated copper sulfate solution will regain its deep blue color.
5. You can transfer the solution to a transparent container for better visibility of the blue color.
It's important to note that the amount of water added should be sufficient to fully rehydrate the anhydrous copper sulfate. Adding excess water may result in a diluted solution, which might appear less intense in color.
(a) might be the result of a chemical change of properties
and i don't know (b) freeze it?
a) ask your teacher
b) go on YouTube so they can give you a lesson