How many sodium atoms in 5.31 grams of sodium carbonate? Na2CO3


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Lia Tan Profile
Lia Tan answered

This just brings me back to my AP Chemistry days, which is a good and bad thing (good because I loved the class, bad because I got a 4 on the test).

So first you need to find the molar weight of the Na2CO3. To do this, look at the periodic table. Na's weight is 22.990 g/mol, C's weight is 12.0111 g/mol, and O's weight is 15.999 g/mol. Therefore, the total weight of one mole of sodium carbonate is:

22.990 g/mol * 2 + 12.011 g/mol + 15.999 g/mol * 3 = 105.988 g/mol

Now you need to find how many moles of sodium carbonate are in 5.31 grams. How you do this is simply dividing 5.31 by 105.988 so you end up with moles as your unit.

(5.31 g) / (105.988 g/mol) = 0.0501 mols

The 2 subscript of Na tells you that for every one mole of sodium carbonate, there are two moles of sodium. Therefore, there are 2* 0.0501 mols = 0.100 mols Na.

To convert from moles to atoms, multiply the amount of moles of sodium to Avogadro's number, which is about 6.02*10^23 mol^-1. The result will be 6.03*10^22 atoms.

It's been a while since I've done this so you should double check. I hope this is right. If not, then I apologize.

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John McCann
John McCann commented
Good choice on the STEM subjects. Do you have calculus?
Lia Tan
Lia Tan commented
Oh yes. I've taken both Calculus AB and Calculus BC which is about equivalent to two years of college calculus.
John McCann
John McCann commented
Then it sounds like you are ready to contribute something to the world and yourself. We have a problem in the US with college students taking mickey mouse courses, running up astronomical debt and then not being able to find a job, or a job commensurate with their schooling.

So, take care and we will see you around here from time to time.

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