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Stoichmetric by gas displacement
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Topic: Stoichmetric by gas displacement (Read 3978 times)
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lokobreed
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Stoichmetric by gas displacement
«
on:
April 24, 2011, 04:25:00 PM »
1) Balance the equations. What mass of KCLO3 decomposed to produce 275 ml of O2 gas at STP.
___ KCLO3 --> __ KCL + __ O2
Balancing would yield
2 KCLO3 --> 2 KCL + 3 O2
I am now confused on the following steps I should take to solve the rest of the problem.
2)Balance the following equation and calculate the volume od hydrogen gas produced from the reaction of .762 g of aluminum when completely reacted with excess hydrochloric acid. The gas was collected over water at 27 C and barometric pressure of 747.
__ Al + HCL --> __ AlCl3 + __ H2
Balancing would yield
2 Al + 6 HCL --> 2AlCl3 + 3 H2
- vapor pressure = 26.7
- pressure of dry hrdrogen = .947 atm
- Kelvin temp = 300 K
I am confused on how to setup the rest of the problem.
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rabolisk
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Re: Stoichmetric by gas displacement
«
Reply #1 on:
April 24, 2011, 04:57:39 PM »
If the question asked, what mole of KClO
3
is decomposed to produce x mol of O
2
gas, could you do it?
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lokobreed
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Re: Stoichmetric by gas displacement
«
Reply #2 on:
April 24, 2011, 05:31:17 PM »
i believe so but I am confused on the meaning of O2 at stp... because wouldnt I need the temperature to solve this?
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rabolisk
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Re: Stoichmetric by gas displacement
«
Reply #3 on:
April 24, 2011, 06:50:55 PM »
STP means Standard Temperature and Pressure.
http://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressure
Question 2 is the same as 1 except you are explicitly given the conditions.
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lokobreed
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Re: Stoichmetric by gas displacement
«
Reply #4 on:
April 24, 2011, 07:06:21 PM »
I am going to attempt snd solve the 2nd one first.
I would first convert how many mols are in .762 g of aluminum = .0282 mols
looking for volume so,
V= nRT/P
V= .0282 * .082 * 300 / .947 = Volume
is this correct?
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rabolisk
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Re: Stoichmetric by gas displacement
«
Reply #5 on:
April 24, 2011, 07:17:15 PM »
You forgot a step. You're looking for the volume of H
2
, not the volume of Al.
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lokobreed
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Re: Stoichmetric by gas displacement
«
Reply #6 on:
April 24, 2011, 07:24:36 PM »
take the .0282 mols of al x 3 mols of H2 / 2 mols of Al = .0424 mols oh H2
Thus V= .0424 mols of H2 * .082 * 300 / .947 = Volume
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rabolisk
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Re: Stoichmetric by gas displacement
«
Reply #7 on:
April 24, 2011, 09:49:25 PM »
Looks good.
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Stoichmetric by gas displacement