Answer:
I think the answer to the question is c
The number of liters of 3.00 M lead (II) iodide : 0.277 L
<h3>Further explanation</h3>
Reaction(balanced)
Pb(NO₃)₂(aq) + 2KI(aq) → 2KNO₃(aq) + PbI₂(s)
moles of KI = 1.66
From the equation, mol ratio of KI : PbI₂ = 2 : 1, so mol PbI₂ :

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So the number of liters(V) of 3.00 M lead (II) iodide-PbI₂ (n=0.83, M=3):

Answer : Average atomic weight of copper atoms will be
63.62 u.
Explanation : For calculating average atomic weight for any given atom we use this formula,
m = Σ

X % abundance
where, m - avg atomic mass of isotope.
and

- mass of isotope
on solving we get,
m = [63 u X (69/100)] + [65 u X (31/100)] = 63.62 u.
The answer has to depend on the mass of the copper that you're trying to melt.
But there is a formula which you can calculate the energy required if you have the information of the mass. This formula requires the value called specific latent heat of fusion, which is the energy required to melt or freeze a specific mass of copper without changing its temperature but change its state.

E is the total energy required, m is the mass, and lv is the specific latent heat of fusion of copper.
Usually, in questions, lv is given. But we can also look it up online which is around 205kJ kg^-1
this means, to melt or freeze a copper, we need to work the mass multiplied by 205kJ in order to calculate its total energy needed or released.