Pb + Mg(NO₃)₂ → Pb(NO₃)₂ + Mg
This reaction would NOT occur because Pb is less reactive than Mg and as such Pb cannot displace the Mg in order for the reaction to occur under normal conditions.
Mg + Fe(NO₃)₂ → Fe + Mg(NO₃)₂
This reaction would occur. This is because Mg is more reactive than Fe and as such can displace it in the reaction, thus allowing the reaction to occur under normal conditions.
Cu + Mg(NO₃)₂ → Cu(NO₃)₂ + Mg
This reaction would NOT occur. Mg is more reactive than Cu, and as such copper cannot displace magnesium in order for the reaction to occur under normal conditions.
The process in which the concentration of the solution is lessened by the addition of water is said to be dilution and equation of dilution relates the initial concentration and volume of stock solution with the final concentration and volume of the solution.
Formula is given by:
(1)
where,
is the initial concentration
is the initial volume
is the final concentration
is the final volume
Now,
= 0.850 M
= 4.12 L
=?
= 10.00 L
Substitute the give values in formula (1),


= 
Thus, the final concentration of the
solution = 
72.71 . simple google search, you shouldnt waste points
From the sun, through the photosynthetic organisms which includes; green plants and algae, then to herbivores to carnivores and decomposers.
I hope this helps answer your question. <3