Explanation:
8% 9:30 pm The binding energy B is the energy associated with the mass difference between the Z protons and N neutrons considered separately and the nucleons bound together (Z+N) in a nucleus of mass M. The formula is B = (Zm, + Nm, - M)c², where mp and m, are the proton and neutron masses and c is the speed of light.
I am going to gamble with Quartz as the material is just the same... As zinc is used to make batteries, It has to be quartz hands down.
PH = -log([H+])
[H+] = 10^(-pH)
[H+] = 10^(-8.78) = 1.65*10^-9
[H+][OH-] = Kw
Kw = 1.0*10^-14 at 25 degrees celsius.
[OH-] = Kw/[H+] = (1.0*10^-14)/(1.65*10^-9) = 6.06*10^-6
The concentration of OH- ions is 6.1*10^-6 M.
Reaction of Cu(NO₃)₂ with each salt is as follow,
1) with KNO₃;
Cu(NO₃)₂ + KNO₃ → Cu(NO₃)₂ + KNO₃
Both salt products are water soluble.
2) With CuSO₄;
Cu(NO₃)₂ + CuSO₄ → CuSO₄ + Cu(NO₃)₂
Again both Salt products are water soluble.
3) With K₂SO₄;
Cu(NO₃)₂ + K₂SO₄ → CuSO₄ + 2 KNO₃
Again both salt products are water soluble.
4) With K₂S;
Cu(NO₃)₂ + K₂S → CuS + 2 KNO₃
In this case CuS is water insoluble, hence precipitates out.
Result:
Option-4 is the correct answer.
