Answer: Event 1 is an example of a physical change and Event 2 is an example of a chemical change.
Explanation: Physical change is one in which there is no change in chemical composition of the substance. There is only a change in phase change.
Chemical change is a change in which there is a change in chemical composition and there might or might not be a phase change.
On Boiling, the water molecules remain bonded in the same form and only covert from liquid to gaseous form, thus is a physical change.
On Rusting of iron nail, the iron changes to iron oxide by combining with oxygen, there is a rearrangement of atoms and thus is a chemical change.

When two atoms are bonded together, the atom that is LEAST likely to attract electrons to itself is
the atom with the smallest electronegativity
Answer:

Explanation:
Hello,
In this case, for the dissociation of calcium fluoride:

The equilibrium expression is:
![Ksp=[Ca^{2+}][F^-]^2](https://tex.z-dn.net/?f=Ksp%3D%5BCa%5E%7B2%2B%7D%5D%5BF%5E-%5D%5E2)
In such a way, via the ICE procedure, including an initial concentration of calcium of 0.01 M (due to the calcium nitrate solution), the reaction extent
is computed as follows:

Thus, the molar solubility equals the reaction extent
, therefore:

Regards.
When a single compound breaks down into two or more compounds or elements in a chemical reaction then it is known as decomposition reaction.
The chemical symbol for sodium carbonate is
.
The decomposition of sodium carbonate is:

The decomposition of sodium bicarbonate,
will result in the formation of sodium oxide,
and carbon dioxide,
.
Hence, carbon dioxide,
will produce with sodium oxide,
on decomposition of
.