Anyone Up Late? Need Help With Chemistry :) (1 Viewer)

[Henry Carmona]

How do i figure this:

Calculate the number of oxygen atoms in 29.34 grams of sodium sulfate, Na2SO4?

I hate chemistry

Anyway, Na=22.99 S=32.07 & O=16.00


I know that if it was just asking how many atoms in 1 mole i could just multiply Oxygen by 4 correct?

That is, (4)(avagadros number) = # of O atoms.

Thanks!

 

[Wayne Bundrick]

It's been 17 years but I'll try.

1 mole of Na2SO4 is
(2 * 22.99) + (32.07) + (4 * 16.00) = 142.05 grams per mole

So 29.34 grams of it is 29.34/142.05 = 0.2065 mole of Na2SO4

4 Oxygen atoms per Na2SO4 molecule * 0.2065 mole of Na2SO4 = 0.8262 mole of Oxygen atoms

"Avocado's number" is 6.02e23 atoms per mole
6.02e23 atoms per mole * 0.8262 mole = 4.97e23 atoms

Somebody check my work please.

 

[Scott_J]

Checking Wayne's work, the numbers are correct and the method seems to be right as well (although it's been a few years since I took Chem).

 

[Scott_MacD]

Correctamundo, Wayne.

It's been a while for me too.

 

[Mark Fitzsimmons]

Do you know the factor label method? Its the easiest way to do these types of problems.

BTW, this is high school chemistry right?

 

[Wayne Bundrick]

For me, it was first year high school chemistry, right about this time of the year in fact.

When I said it's been 17 years that got me thinking. I've reached the age where I've been out of school longer than I was in school, not counting college. I've reached the Middle Ages!

 

[Ryan Wishton]

I took Chemistry for a year... Got an A in the class both times... The weird thing is if you showed me anything now, I wouldnt know what to do with it... Same with all those math formulas...

Like High School entirely, I barely remember a thing...

Terrible memory maybe??? Maybe I have amnesia???

I tend to only remember things that interest me...