If you have 200 grams of Na_2O, how many moles of Na_2O do you have?

1 Answer
anor277
Apr 7, 2016

You have 3 and a bit moles of sodium oxide.

Explanation:

"Moles "= " Mass"/"Molar mass" = (200*g)/(61.98*g*mol^-1) = ??" moles"

The signal advantage of doing calculations this way, i.e. including units in the calculation is that it adds an extra level of validation. I wanted an answer in "moles". The calculation as given me an answer in "moles", i.e. (200*cancelg)/(61.98*cancelg*mol^-1) = ?mol. Why? Because 1/x^-1 = 1/(1/x) = x

This is an example of dimensional analysis. You can get very good at it and introduce another level of checking your answser.

Related questions
See all questions in The Mole
Impact of this question
1795 views around the world
You can reuse this answer
Creative Commons License