Question

In a 1.0M solution of Ca(NO3)2 how many mole of NO3-ions are present?

Answer 1

Well, if we assume a `1*L` volume of solution....

Explanation:

...then clearly TWO moles of nitrate ions are present. Why?

Well we know that by definition,

`"concentration"="moles of solute"/"volume of solution"`

And since clearly each equiv of calcium nitrate delivers TWO equiv of nitrate ion to solution...the solution has a `2*mol*L^-1` concentration with respect to nitrate ion. Capisce?

Note that we had to specify a solution volume even tho we knew the solution concentration.....