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Chemistry Homework Help => General Chemistry => Topic started by: DesertRose on April 30, 2010, 07:46:44 PM

Title: converting grams to molecules
Post by: DesertRose on April 30, 2010, 07:46:44 PM
Hi, my question is this; i am given a question that says.35g BaOH to molecules.
i worked it out and my answer is 1.36 * 10^21, is that correct???
and by chance, is there any simple method to see if your answer is correct or if it is supposed to be in that range of values?? (i have now starting this topic)
Any assistance would be greatly appreciated!!!
thank you!!
Title: Re: converting grams to molecules
Post by: uma on April 30, 2010, 09:09:25 PM
Ba(OH)2 is the correct formula
Number of molecules = number of moles X Avogadro 's number

number of moles = mass in gms X molar mass
molar mass of Ba(OH)2 = 171.3425 g/mol
No of moles = 0.35/ 171.3425 g/mol
Avogadro's number = 6.022 X 10 ^23
Number of molecules = 6.022 X 10 ^23  X  0.35/ 171.3425 g/mol
Now you can check your answer
Title: Re: converting grams to molecules
Post by: DesertRose on April 30, 2010, 09:44:37 PM
thank you!!