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Topic: Determine empirical formula of the oxide.  (Read 10404 times)

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Offline saiyanmx89

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Determine empirical formula of the oxide.
« on: February 12, 2009, 08:24:33 PM »
A sample of phosphorus weighing 0.500g was ignited in pure oxygen. The mass of the oxide formed is 1.145g. Determine the empirical formula of the oxide.
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #1 on: February 12, 2009, 08:50:52 PM »
Dear saiyanmx89;

And your Work/Assumption is: ?,   ─    And would you please read:  "Forum Rules" (4.)

Good Luck!
                    ARGOS++
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #2 on: February 12, 2009, 09:01:03 PM »
I'm not asking anyone to do this problem for me. I'm just not sure how to start it.
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #3 on: February 12, 2009, 09:07:28 PM »

Dear saiyanmx89;

Do you know how many moles 0.500g P is?
How much is left for oxygen in the mass of oxide, and how many moles O is that?
Then build the ratio.

Good Luck!
                    ARGOS++
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #4 on: February 12, 2009, 09:08:46 PM »
There are 0.0161 mol P. How do I find how much is left for oxygen?
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #5 on: February 12, 2009, 09:16:59 PM »
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #6 on: February 12, 2009, 09:19:42 PM »
The difference is 0.645g. So, then you would have 0.0403 mol O originally right?
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #7 on: February 12, 2009, 09:21:49 PM »
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #8 on: February 12, 2009, 09:22:33 PM »
Would you then divide the moles of P by itself the moles of O by the moles of P to get: PO3?
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #9 on: February 12, 2009, 09:28:29 PM »

Dear saiyanmx89;

No!, -  What is 0.0403 moles div. 0.0161 moles?
And what have you to do if you will get a broken number?

Good Luck!
                    ARGOS++
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #10 on: February 12, 2009, 09:35:45 PM »
I'm not sure what ratio that's making then.
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #11 on: February 12, 2009, 09:39:57 PM »

Dear saiyanmx89;

For me:  0.0403 moles O div. 0.0161 moles P =  2.5  O/P.
And what you have to do now?

Good Luck!
                    ARGOS++
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #12 on: February 12, 2009, 09:41:30 PM »
you round to the nearest whole number, right? so 3?
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Offline ARGOS++

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Re: Determine empirical formula of the oxide.
« Reply #13 on: February 12, 2009, 09:51:03 PM »
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Offline saiyanmx89

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Re: Determine empirical formula of the oxide.
« Reply #14 on: February 12, 2009, 09:53:56 PM »
I don't understand what you mean. How do I add another P?
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