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Offline DesertRose

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Conversion question
« on: April 29, 2010, 06:38:48 PM »
Hi, i am given a question that says;

Convert 0.35g BaOH to molecules. I am not really sure as to how to work it out. I did attempt it, converting it to moles and then molecules but i think i got the wrong answer. i got -9.222 * 10^25.

can anyone assist me by telling me the process to arrive at the correct answer??
and assistance would be greatly appreciated!!!
thank you!!!

Offline DemonicAcid

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Re: Conversion question
« Reply #1 on: April 29, 2010, 06:45:05 PM »
Looks like you have approximately the right order of magnitude and your stated method is correct. Check your calculator. It helps to do everything individually to avoid order of operations errors.

Offline DesertRose

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Re: Conversion question
« Reply #2 on: April 29, 2010, 06:50:35 PM »
Thank you! But by chance, is it possible to get molecules in a negative number (like the one i got?)
Again, thank you!

Offline DemonicAcid

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Re: Conversion question
« Reply #3 on: April 29, 2010, 06:57:20 PM »
No, number of molecules must be positive.

Offline DesertRose

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Re: Conversion question
« Reply #4 on: April 29, 2010, 07:20:01 PM »
Thank soo much for your assistance!!!!!!

Offline Borek

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Re: Conversion question
« Reply #5 on: April 30, 2010, 02:56:01 AM »
Actually 1025 looks like several orders of magnitude too much. With molar mass of barium hydroxide close to two hundred, given mass of substance must be in the 10-2 moles range (if not less), that means 1021 molecules, not 1025. And you don't need a calculator to see that.
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Offline DemonicAcid

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Re: Conversion question
« Reply #6 on: April 30, 2010, 11:59:24 AM »
I noticed that later on. Doing thermo caused me to mix up my physical constants.

Offline DesertRose

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Re: Conversion question
« Reply #7 on: April 30, 2010, 06:49:56 PM »
Thank you!!
I used another method, and this answer looks more correct since you said that 10^21 should be the appproximate number. My answer is, 1.36 * 10^21.

Is that correct???

Any assistance would be kindly appreciated!!

Offline Borek

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Re: Conversion question
« Reply #8 on: May 01, 2010, 04:20:42 AM »
My answer is, 1.36 * 10^21.

Is that correct???

No, as explained elsewhere.
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