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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: matt1234 on October 14, 2009, 08:20:25 PM

Title: Molar mass practice problems
Post by: matt1234 on October 14, 2009, 08:20:25 PM

Hello all

Would someone be kind enough to look over these questions to see if i did them correctly, i do not have answers to them. 

Thank you!

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Title: Re: Molar mass practice problems
Post by: Ak on October 14, 2009, 10:57:38 PM

i didnt check your calculations or numbers u used but the method is correct

basically:

g/mol * mol = g

and

g / (g/mol) = g*mol/g = mol

Title: Re: Molar mass practice problems
Post by: matt1234 on October 15, 2009, 07:12:39 AM

thank you ill have my teacher glance over them and will post back.

Title: Re: Molar mass practice problems
Post by: sjb on October 15, 2009, 01:12:34 PM

All seem OK at a first glance except practice problem e). What is the atomic weight of Cl (hint, see second sheet)?

Title: Re: Molar mass practice problems
Post by: JGK on October 15, 2009, 03:58:09 PM

4 moles of Phosphorus atoms 31g /mole =124 g

4 moles of Phosphorus as P₈, this is a bit ambigous and may be a trick question, personally I think the answer is once again 124 g.

The way the question is worded is asking for the weight of 4 moles of Phosphorus as P₈ and not 4 moles of P₈.

4 moles of Phosphorus is eqiivalent to 0.5 moles P₈

Title: Re: Molar mass practice problems
Post by: matt1234 on October 15, 2009, 07:00:47 PM

Thanks guys you folks are the best. :) Glad im on the right track.