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# Help with chem please ! realy simple q. on moles.....

1. theres an attachment below with the q. and the solution but i reallly dont understand why they divide by 32 ? i thought ur supposed to divide by 16 which is the mr of oxgyen?
thanks so much
Attached Images

2. Oxygen gas in its natural state is diatomic.

I.e. O2

You're right, the molar mass is 16 grams per mole, but as it's diatomic, you multiply by 2, thus getting 32.

Hope that helps
3. (Original post by Chrisofsmeg)
Oxygen gas in its natural state is diatomic.

I.e. O2

You're right, the molar mass is 16 grams per mole, but as it's diatomic, you multiply by 2, thus getting 32.

Hope that helps
ohhhh okay thanks i thought only if there were a number in front of the element then you would take notice of it , i didnt realise the little 2 made a difference ..... if that makes sense :s haha
thanks again anyway
4. (Original post by starandsmile)
ohhhh okay thanks i thought only if there were a number in front of the element then you would take notice of it , i didnt realise the little 2 made a difference ..... if that makes sense :s haha
thanks again anyway
No worries mate. If you want anymore help feel free to drop me a PM
5. (Original post by Chrisofsmeg)
No worries mate. If you want anymore help feel free to drop me a PM
thanks

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