Question

help please!!! trying to find out what the total number of ions is in 3.18g of SrCl2? I got molar mass as 158.53 g/mol, 3 ions, and 2.28x10^24 for the formula units of SrCl2...not sure how to put this info together though to find how many ions are in 3.18g of SrCl2??

Answer 1

We start off by knowing what is the molar mass of SrCl2, and from there we get the moles of SrCl2

Now, we have the moles of SrCl2, the next step is to determine how many molecules does this compound have.

We know that every compound consist of 6.022x10^23 (Avogadro's number) molecules or formula units, so we times the moles of SrCl2 by the molecules.

We also know that a single molecule consists of 3 ions in total, because:
\(\Large Sr^{2+}_{(aq)}+2Cl^{-}_{(aq)} \rightarrow SrCl_{2{(s)}}\)

There's 1 mol of Sr+ ion and 2 moles of Cl- ions. 1+2=3 ions in total.

Finally, to get the total number of ions, we times the molecules we got by the total number of ions because each molecule have 3 ions.