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

[axer]

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?

 

[mfb]

in every O2 molecule, there are 2 moles of O.

In every single molecule?

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.

 

[axer]

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?

 

[Borek]

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?

 

[axer]

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

 

[mfb]

Oh.. so the number of molecules is just no. of moles times molar mass?
no need to multiply by 2?

Right.

 

[epenguin]

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.

 

[Borek]

Right.

Beware: part of the OP answer was plainly wrong.