Calculate the number of molecules of O2 when given the number of moles

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Discussion Overview

The discussion revolves around calculating the number of molecules of O2 given a specific number of moles, specifically 1.82 moles. Participants explore the relationship between moles, molecules, and the concept of molar mass.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant calculates the number of molecules of O2 by multiplying the number of moles (1.82) by 2, leading to a claim of 3.65 moles of oxygen atoms, then further calculates the total number of molecules as 2.19×10^24.
  • Another participant challenges the initial calculation, stating that the number of molecules should not involve multiplying by 2, as the question specifically asks for O2 molecules, not oxygen atoms.
  • There is confusion about the relationship between moles and molecules, with some participants suggesting that the number of molecules is simply the number of moles multiplied by Avogadro's number (6.022×10^23).
  • One participant attempts to clarify the concept of a mole by comparing it to a dozen, emphasizing that the calculation should focus on the number of molecules directly from the number of moles.
  • Another participant points out that part of the original answer was incorrect, indicating that there are misunderstandings present in the discussion.

Areas of Agreement / Disagreement

Participants express disagreement regarding the correct method to calculate the number of O2 molecules from moles, with no consensus reached on the proper approach. Some participants believe the initial calculation was flawed, while others defend it.

Contextual Notes

There is a lack of clarity regarding the definitions and relationships between moles, molecules, and molar mass, leading to confusion in the calculations presented. The discussion also reflects varying levels of understanding among participants.

Who May Find This Useful

This discussion may be useful for students learning about stoichiometry, particularly in understanding the conversion between moles and molecules in chemical calculations.

axer
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Homework Statement


After balancing an equation, there are 1.82 moles of O2.

Calculate the number of molecules of O2. given moles.

Homework Equations

The Attempt at a Solution


in every O2 molecule, there are 2 moles of O.
so if the number of moles of O2 molecule is 1.82. then 1.82*2= 3.65 moles.

number of molecules= 3.65*6.022*10^23= 2.19*10^24.
Correct?
 
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axer said:
in every O2 molecule, there are 2 moles of O.
In every single molecule?
axer said:
number of molecules= 3.65*6.022*10^23= 2.19*10^24.
Correct?
That is the number of oxygen atoms. The question asked about the number of O2 molecules.
 
mfb said:
In every single molecule?That is the number of oxygen atoms. The question asked about the number of O2 molecules.
Oh.. so the number of molecules is just no. of moles times molar mass?
no need to multiply by 2?
 
axer said:
Oh.. so the number of molecules is just no. of moles times molar mass?

Number of moles times molar mass is a sample mass.

Think about a mole as of an overgrown dozen, with 6.02×1023 objects instead of 12. You have two dozens of molecules - how many molecules? You have two moles of molecules - how many molecules?
 
Borek said:
Number of moles times molar mass is a sample mass.

Think about a mole as of an overgrown dozen, with 6.02×1023 objects instead of 12. You have two dozens of molecules - how many molecules? You have two moles of molecules - how many molecules?
2*6.02×1023

the question included no of moles
 
axer said:
Oh.. so the number of molecules is just no. of moles times molar mass?
no need to multiply by 2?
Right.
 
Maybe you have go the question confused with the other possible similar kind of questions.
Forget everything you know about oxygen - it's irrelevant here.
Calculate the number of molecules of anything in 1.82 moles of that thing.
Is the same for anything.
 
mfb said:
Right.

Beware: part of the OP answer was plainly wrong.
 

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