If a sample of BaSO3 is found to contain 1.73 · 1018 SO32- ions how many moles of Ba2+ ions are present? Express your answer in scientific notation.
The following information is given:
Molar Mass (g/mol)
BaSO3 217.39
Ba2+ ion 137.33
SO32- ion 80.063
Avogadro's No. (mol-1)
6.022×1023
Ans: 2.8727 x 10^-6
I'm really confused here. I guess I would have to find out what percentage of SO3 2- ions make up of BaSO3 and then figure out how much BaSO3 I have in all, then determine how many Ba2+ ions there are? If so I'm unsure of how to go exactly do it.
No. BaSO3 has one ion of sulfite per Ba ion. So the number of Ba+2 ions is 1.73E18
Moles Ba+2= 1.73E18/6.02E23
Oh I see...I was making it complicated
So if the ratio wasn't 1 to 1 like in the following..
Na2SO3 is found to contain 2.37 · 10-3 mol of Na+ ions
then I would have to use dimensional analysis to solve?
If it had 2.37E-3mole ofNa ions, then the number of Na2SO3 would be 1/2 * 2.37E-3 mol
hmm okay.
So when do you know if your suppose to divide by Avogadro's number as you did in the first problem or multiply by the ratio as you just did?