Answer:

Explanation:
At
, the heat of vaporization of water is given by:

The water here condenses and gives off heat given by the product between its mass and the heat of vaporization:

The block of aluminum absorbs heat given by the product of its specific heat capacity, mass and the change in temperature:

According to the law of energy conservation, the heat lost is equal to the heat gained:
or:

Rearrange for the final temperature:

We obtain:

Then:

I don't know what the options were but a material that is very likely going to be challenging to recognize under a microscope as a mixture is a homogeneous mixture. A homogenous mixture is uniform and thus hard to recognize as a mixture. An example is water!
Answer:
2) Copper (II) Chloride
Explanation:
A precipitate will form if the resulting compound is insoluble in water. For example, a silver nitrate solution (AgNO3) is mixed with a solution of magnesium bromide (MgBr2).
Its 4 dude i did this already