Your question isn't quite clear, but if you're wondering if a chemical is polar or non-polar, you simply draw a VSEPR sketch and draw arrows where the bonds are. Only draw arrows between atoms, NOT between an atom and a lone pair of electrons. The arrow should point to the most electronegative atom (you should be given an electronegativity scale). Afterwards, you add up the arrows as vectors, and look at the sum of the vectors. If the sum is zero (CH4 is a good example), the chemical is non-polar. If the sum is a vector, the chemical is polar (H2O, or water, is polar).
Answer:

Explanation:
Hello,
In this case, as the copper's heat loss is gained by the water, the following energetic relationship is:

Therefore the equilibrium temperature shows up as:

Thus, by knowing that water's heat capacity is 4.18J/g°C, one obtains:

Best regards.
Explanation:
Once solid ammonium nitrate interacts with water, the molecules of polar water intermingle with these ions and attract individual ions from the structure of the lattice, that actually will break down. E.g;-NH4NO3(s) — NH4+(aq)+ NO3-(aq) To split the ionic bonds that bind the lattice intact takes energy that is drained from the surroundings to cool the solution.
Some heat energy is produced once the ammonium and nitrate ions react with the water molecules (exothermic reaction), however this heat is far below that is needed by the H2O molecules to split the powerful ionic bonds in the solid ammonium nitrate.
Hence, we can say that the dissolution of ammonium nitrate in water is highly endothermic reaction.