How Many Moles of Oxygen Gas Are Produced from Decomposing Hydrogen Peroxide?

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Discussion Overview

The discussion revolves around calculating the number of moles of oxygen gas produced from the decomposition of hydrogen peroxide (H2O2) in a specific solution. Participants explore the calculations involved in determining the moles of oxygen gas generated from a given volume and concentration of H2O2, addressing potential errors in their calculations.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant calculates the mass of the H2O2 solution and attempts to find the moles of oxygen gas produced, but their initial answer is rejected.
  • Another participant questions the molar mass of H2O2, suggesting it should be 34.016 g/mol instead of 18.016 g/mol.
  • A participant acknowledges the correction of the molar mass and mentions that their recalculations still yield incorrect results.
  • One participant requests clarification on the current calculations, noting that there are several issues with the way the amount of oxygen was calculated.
  • It is pointed out that the conversion from moles of atomic oxygen to moles of molecular oxygen (O2) was incorrectly handled in the calculations.
  • There is a suggestion that the rejection of the answer could be due to incorrect significant digits in the calculations.

Areas of Agreement / Disagreement

Participants express disagreement regarding the correct molar mass of H2O2 and the calculations leading to the moles of oxygen gas produced. The discussion remains unresolved as participants continue to identify potential errors without reaching a consensus.

Contextual Notes

Participants have not fully resolved the assumptions regarding significant figures and the correct conversion between atomic and molecular oxygen, which may affect the calculations.

chakakhan
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Homework Statement



Calculate the number of moles of oxygen gas produced from the completely catalyzed decomposition of 6.60ml sample of a 3.5% solution of H2O2. The density of the 3.5% solution of H2O2 is 1.01 g/ml.

Homework Equations


2(H2O2) --> 2(H2O) + O2
p=m/v



The Attempt at a Solution


I used. 1.01g/ml=m/6.6ml to get 6.1206g of the solution
Multiplied 6.1206 by .035 to get .214221g H2O2
.214221g H2O2(1mol H2O2/18.016g H202)(2 mol O/2mol H2O2)(16g O/1 mol O) yields .1897g O
.1897g O (1 mol O/16g O) yields .0118 mol O. This answer was rejected. I even tried .0236 since the equation shows O2, just to be sure. Wrong as well.
 
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If O is 16 g/mole, and H is 1 g/mole then H2O2 is ? g/mole? Not 18.016.
 
Right, I caught that. It should be 34.016g. I ran the same calculations with that number, but to no avail.
There was also actually 6.666g of solution, but what I've tried with that number is still wrong.
 
Please show your results now - there are several problems with the way you calculated amount of oxygen, but as you corrected some of them it is not clear what is the current version of your calculations, so it is not possible to check it.

Moles of oxygen gas means moles of O2. But

chakakhan said:
.0118 mol O. This answer was rejected. I even tried .0236 since the equation shows O2

this is wrong - 0.0118 mol of atomic O is not equivalent to 0.0236 moles of O2.

It is also possible system rejects answer that is technically correct, but has wrong number of significant digits.
 

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