Use the equation d=m/v
your mass or "m" is 78 g
your volume or "v" is 60mL
if you plug those values into the equation it will look like this:
d=78/60
d=1.3g/mL should be what you come up with
If you melt and cool silicon dioxide under very special conditions
<span>in the laboratory we can grow a single </span>crystalline<span> form of </span>
<span>silicon dioxide that we call quartz. In quartz crystals all of </span>
<span>the molecules are aligned and bonded together in a regular three </span>
<span>dimensional tetrahedral structure forming a very hard, transparent </span>
<span>material with special electronic properties. </span>
I believe the answer is C