first there is only 25 points on here because if you add 50 points to the question brainly divides it by two so that two people can answer so if you want each person to get 50 points or to advertise how much point sis on this quetstion you would instead need to add 100 points to the question- anyways let's answer this question now
Do you know what the Law of Conservation of mass says? Matter is neither created nor destroyed. Therefore, you have started with 12.7 g Cu and 3.2 g S on the left for a total of 15.9 g; therefore, you must obtain 15.9 g of product(s). If Cu2S is the only product there must be 15.9 g Cu2S.
Answer:
2.16 MeV
Explanation:
To determine the amount of work done that is needed to assemble the atomic mass; we need to apply the equation;
U = 
where:
= proportionality constant = 
e = magnitude of the charge of each electron = 
r = length of each side of the vertex = 
So; replacing our values into above equation; we have:
U = 
U = 3.456 × 10 ⁻¹³ J
If we have to convert our unit from J to Mev; then we are going to have:
U = 3.456 × 10 ⁻¹³ J 
U = 2.16 MeV
Therefore, the amount of work done needed to assemble an atomic nucleus = 2.16 MeV