January 25, 2021, 04:17:09 PM
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Topic: What's left?  (Read 12628 times)

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Offline Kryolith

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Re: What's left?
« Reply #15 on: January 20, 2008, 04:41:55 PM »
From there then, i take 0.16 moles from 0.18 moles to give 0.02 moles??? How does that convert to grams?

Sorry I haven't read this. The answer is correct. Conversion to mass is easy: m=M*n

submar1ney

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Re: What's left?
« Reply #16 on: January 20, 2008, 05:41:15 PM »
Ok guys, here's what i get from a similar example.

Given 12.6g of 2HNO3 and 15g of CaCO3, how much CaCO3 is left after the reaction is over.

2 moles of 2HNO3=126.02g  and  1 mole of CaCO3 = 100.1g

100.1 : 164.1 = 15g : x

x = (100.1 / 126.02) x 12.6g = 10g of CaCO3 left over???

Hope so...

Cheers


Offline Kryolith

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Re: What's left?
« Reply #17 on: January 20, 2008, 05:45:35 PM »
15g - 10 g (0.1 mol) = 5 g left over...
assuming that you start with 12.6 g HNO3
if you start with 6.3 g  you are right.

Offline Borek

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Re: What's left?
« Reply #18 on: January 20, 2008, 05:47:45 PM »
x = (100.1 / 126.02) x 12.6g = 10g of CaCO3 left over???

Kryolith already gave you the final answer - you made small mistake. You have CORRECTLY calculated mass of calcium carbonate that REACTED. You have just forgot the final step.
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submar1ney

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Re: What's left?
« Reply #19 on: January 20, 2008, 05:48:20 PM »
Ah so what i calculated is the amount used in the reaction?

Offline Borek

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Re: What's left?
« Reply #20 on: January 20, 2008, 05:50:34 PM »
Ah so what i calculated is the amount used in the reaction?

Exactly :)
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submar1ney

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Re: What's left?
« Reply #21 on: January 20, 2008, 05:53:50 PM »
Ah so what i calculated is the amount used in the reaction?

Exactly :)

Ok...  just to clear up my confusion..  hahaha   I calculated the amount of CaCO3 used in the reaction, so subtract this from the original amount of 15g i'm left with 5g of CaCO3?

I love chemistry  :P

Offline Kryolith

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Re: What's left?
« Reply #22 on: January 20, 2008, 05:57:08 PM »
15g - 10 g (0.1 mol) = 5 g left over...

Congratulation. You got it!  :)

submar1ney

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Re: What's left?
« Reply #23 on: January 20, 2008, 06:00:34 PM »
:) thanks for all your help guys ;-)

Have a good night.

Offline Mitch

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Re: What's left?
« Reply #24 on: January 20, 2008, 06:29:35 PM »
Very god job all.

5 scooby snacks given to Kryolith, Borek and Alpha-Omega.
« Last Edit: January 16, 2012, 03:06:44 PM by Arkcon »
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