<span>To work out the volume of something from its density, use the compound measures triangle: mass over density and volume. To find volume that the beaker holds, divide the mass by the density. V = (388.15 - 39.09)/1. V = 349.06g/cm3. To find the weight of the beaker and the contents, first work out the weight (mass) of the mercury, with this formula: mass = d x v. M = 13.5 x 349.06. M = 4712.31. Then add on the weight of the beaker (39.09g). The total weight is 4751.40g.</span>
Sodium/natrium is a metal from first column group so it should have one 1+ charge. Phosphate ion has 3- charge. That is why there 3 natrium ion for 1 phosphate ion when this molecule is dissolved in water. The ion formula would be:
(Na)

(PO

) ==> 3 Na

+ PO
Sodium, Atomic mass: 22.989769 g
You can see in a periodic table