Which best describes a compound such as sodium chloride?

 Sodium can only be separated from Chloride by chemical means e.g.  electrolysis.

It would be nice if you could state your possible options so it would be easier to confirm but here is what I can best describe about sodium chloride.

Sodium Chloride is a Pure Substance that can be chemically separated.

a: 45.9 meters

b: 4.29 seconds

step-by-step explanation:

a: h(t)=1/2(-9.8)(3)^2+0(3)+90

h(t)=-4.9(3)^2+90

h(t)=-44.1+90

h(t)=45.9 meters

b: 0=1/2(-9.8)(t^2)+0t+90

0=-4.9t^2+90

-90=-4.9t^2

18.37=t^2

t=4.29 seconds

in the second question, the numbers aren't exact, but they're a close approximation.