Answer:
Step-by-step explanation:
When anhydrous copper(II) sulfate (CuSO4) is exposed to the atmosphere for two days, it undergoes a noticeable change. Anhydrous copper(II) sulfate is a white powder with no water molecules bound to its crystal structure. However, when exposed to the moisture present in the atmosphere, it readily absorbs water molecules through a process called hydration.
As copper(II) sulfate absorbs water, it undergoes a chemical reaction and forms hydrated copper(II) sulfate, which is a blue crystalline solid. The reaction can be represented as follows:
CuSO4 (anhydrous) + H2O (moisture) → CuSO4·xH2O (hydrated)
The value of 'x' in CuSO4·xH2O represents the number of water molecules that have been incorporated into the crystal structure of copper(II) sulfate.
So, after two days of exposure to the atmosphere, the anhydrous copper(II) sulfate would have absorbed water molecules, resulting in the formation of hydrated copper(II) sulfate. The color of the substance would change from white to blue due to the presence of water molecules within its crystal lattice.
The exact appearance and properties of the hydrated copper(II) sulfate will depend on the specific conditions and the level of hydration. The most common form of hydrated copper(II) sulfate is pentahydrate, CuSO4·5H2O, which is a bright blue compound commonly known as blue vitriol or copper sulfate pentahydrate.
Overall, the observation made when anhydrous copper(II) sulfate is exposed to the atmosphere for two days is the transformation of its color from white to blue due to the absorption of moisture and the formation of hydrated copper(II) sulfate crystals.