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### Topic: Please calculate the number of mols of oxygen gas produced per second  (Read 63401 times)

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#### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #30 on: March 14, 2008, 06:48:35 PM »
The iodidie ion is the catalyst? #### Padfoot

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• Mole Snacks: +23/-2 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #31 on: March 15, 2008, 12:12:26 AM »
The iodidie ion is the catalyst? Yes - I'm pretty sure I- can be a catalyst - I remember it from one of my lectures last year.

H2O2 + I- --> H20 + IO-
IO- + H202 ----> H20 +O2 +I-

2H202 -----> 2H20 + O2

#### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #32 on: March 15, 2008, 01:09:52 AM »
hmm.. my chemistry and physics teachers might be wrong then #### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #33 on: March 15, 2008, 01:10:54 AM »
How would I use the balanced equation to determine the number of mols of hydrogen peroxide decomposed per second?

#### Padfoot

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• Mole Snacks: +23/-2 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #34 on: March 15, 2008, 05:33:25 AM »
How would I use the balanced equation to determine the number of mols of hydrogen peroxide decomposed per second?

Anyway, we did establish, I believe, that we won't be using the reaction, as volume of O2 was a given. #### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #35 on: March 15, 2008, 10:50:23 AM »
Quote from: Marcus Soutlo on Yesterday at 07:10:54 PM
How would I use the balanced equation to determine the number of mols of hydrogen peroxide decomposed per second?

Quote from: Arkcon on Yesterday at 11:59:42 AM
Anyway, we did establish, I believe, that we won't be using the reaction, as volume of O2 was a given.

Can you please specify what you mean?

God bless

#### Arkcon ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #36 on: March 15, 2008, 11:07:25 AM »
Quote from: Marcus Soutlo on Yesterday at 07:10:54 PM
How would I use the balanced equation to determine the number of mols of hydrogen peroxide decomposed per second?

Quote from: Arkcon on Yesterday at 11:59:42 AM
Anyway, we did establish, I believe, that we won't be using the reaction, as volume of O2 was a given.

Can you please specify what you mean?

God bless

OK, review the enhanced portions of the original post:

Please calculate the number of mols of oxygen gas produced per second
Remember PV=nRT and that you must account for the partial pressure of water vapour.

The reactions conditions are:
Atmospheric pressue:102.6 kPa;
Temperature:290 K
Partial pressure of water vapour:1.94 kPa.

The reaction is:
Volume of 6% H2O2 (mL):10.0
Volume of distilled water (mL):0.0
Volume of 1.0 M NaI (mL):10.0
Volume of distilled water (mL):0.0
O2 production in 60 s (mL):151.0 What I have done thus far is rearranged the Ideal Gas Law in order to get the number of mols

n = PV/RT

Is this the correct first step Also, I have substituted the following values into the equation:
P = 102.6 kPa
V = ?
R = 8.3145 J/mol K
T = 290 K Thank you for any help it is greatly appreciated.

Could you quote and highlight your new question again, giving all the given information, regarding the moles of H2O2 decomposed, and the order of the reaction?  Have you solved this original one?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

#### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #37 on: March 15, 2008, 11:27:17 AM »
Absolutely,

The question did not ask us to solve for the order of the reaction yet.  For the moles of O2 produced, I received an answer of 0.00003846 mol per second, or 0.0023076 mol per minute of O2 gas produced.

The information given regarding the relationship between O2 and H202 is the balanced equation. Thus, from knowing the number of coefficients in the balanced equation, this is how I can solve for the number of moles of hydrogen peroxide decomposed?

#### Padfoot

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• Mole Snacks: +23/-2 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #38 on: March 16, 2008, 02:40:38 AM »
I received an answer of 0.0023076 mol per minute of O2 gas produced.
http://www.chemicalforums.com/index.php?topic=24222.msg91844#msg91844 #### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #39 on: March 16, 2008, 10:39:32 AM »
THe reason the two answers are different is because the lab asks to find out 5 different answers for 5 seperate reactions

#### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #40 on: March 16, 2008, 01:47:49 PM »
Sorry if I confused anyone

I only need to know how to use the balanced equation to determine the number of mols of hydrogen peroxide decomposed per second?

Of the two reactions I did, I got two answers, according to my calculations, of

0.0023076 mol per minute of O2 gas produced

and

0.0062990 mol per minute of O2 gas produced

Lets say I choose 0.0023076 mol per minute of O2 gas produced. How can I determine the number of mols of hydrogen peroxide decomposed per minute from this? I know that I then need to divide by 60 but I am stuck on the first step.

Again, sorry for any confusion I may have caused #### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #41 on: March 16, 2008, 06:42:03 PM »
One of my reactions is:
Volume of 6% H2O2 (mL):10.0
Volume of distilled water (mL):0.0
Volume of 1.0 M NaI (mL):10.0
Volume of distilled water (mL):0.0
O2 production in 60 s (mL):151.0

I have collected oxygen gas by the downward displacement of water (results are in the last column).  This oxygen was produced in the first 60 s of the reaction.

Im asked to calculate the change in hydrogen peroxide concentration per second.  This is the rate.  (Hint:  What volume of liquid does the hydrogen peroxide now occupy?).

I know that

rate = change in concentration / time

But how do I get change in concentration? #### Borek ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #42 on: March 16, 2008, 06:56:11 PM »
From reaction equation. You know how much oxygen was produced per minute, you can calculate how much hydrogen peroxide was consumed. Simple stoichiometry.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info, pH-meter.info

#### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #43 on: March 16, 2008, 07:13:57 PM »
b)   Write a complete balanced equation and use it to determine the number of mols of hydrogen peroxide decomposed per second.

c)   Calculate the change in hydrogen peroxide concentration per second.  This is the rate.  (Hint:  What volume of liquid does the hydrogen peroxide now occupy?).

So what is the difference between the number of mols of hydrogen peroxide decomposed per second in part b and the change in hydrogen peroxide concentration per second in part c?

Thank you again #### Marcus Soutlo

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• Mole Snacks: +2/-13 ##### Re: Please calculate the number of mols of oxygen gas produced per second
« Reply #44 on: March 17, 2008, 07:09:51 AM »
H2O2                                                                          NaI
Reaction   Volume of 6% H2O2 (mL)  Volume of distilled water (mL)  Volume of 1.0 M NaI (mL)  Volume of distilled water (mL)  O2 production in 60 s (mL)
1               10.0                                0.0                              10.0                             0.0                               151.0
2               8.0                                2.0                              10.0                             0.0                                 93.0
3               6.0                                4.0                              10.0                                0.0                                      61.0
4               4.0                                6.0                              10.0                             0.0                                      41.0
5               10.0                                0.0                                8.0                             2.0                                 99.0
6               10.0                             0.0                                6.0                             4.0                                 73.0
7               10.0                                0.0                                4.0                             6.0                                 44.0

The above table is the information I am given. Say I choose reaction 2.

what is the difference between the number of mols of hydrogen peroxide decomposed per second in part b and the change in hydrogen peroxide concentration per second in part c?

My guess is it has something to do with the distilled water volume?