I'm wondering how to find the molar mass of a compound (sodium chlorite), as well as the mass of each element within the compound.

Question

I found the answer online, but Wyzant is not letting me reply to the tutor's comment. So, I created a question.

Answer 1

Hi Jackson S.,

You get a Periodic Table of the Elements, generally it has masses for each element. You look those up, you don't reason them out, for reasons I'd be happy to discuss, if you so indicate by a comment.

You write the chemical formula for sodium chlorite. If you have to build this up from scratch, you do as follows:

sodium = Na⁺¹ (as an ion)(doesn't affect the mass that it's an ion, by the way)

chlorite = core of chlorine; the ending indicates that it's not Cl- (chloride), nor has one more O attached (ClO)^- = hypochlorite), but does have 2 more O's attached (ClO₂)^- . There are also designations for 3 O's attached (chlorate = ClO₃^-) and 4 O's attached (perchorate = ClO₄^- ), by the way.

Since your + and - charges balance, your simplest formula is NaClO₂ .

Next, you go through that formula, and add up the respective element masses. In the case of O, you add it in twice, since there are 2 of them. Kabish?

the sum is your molar mass, or formula weight, to use an older term.

And by the way, if you respond to an Ask-the-Expert answer, there's no sure-fire way to make sure your query is read. you might pose a comment, and hope (it's a slim chance) that the tutor reviews his/her comments periodically. I answer a lot of these questions, and I've asked Wyzant if they could tag questions that have comments on them. Otherwise, I'd have to open each answered question (I'm at ~1050 and going strong!) and inspect it. So far, no action from Wyzant. You can understand their perspective -- they'd much prefer you get a full-time tutor, if you have a lot of questions!

-- Cheers, _-- Mr. d.