[samiam]

2h2+o2<-->2h20

so the question is how many hydrogen atoms are there in h2.

is this right 2mol h2 * (6.022*10^23 molecules h2)/(1 mol h2) *(2 atoms H/ 1 molecule of h2)

or
4 mol H*( 6.022*10^23 atoms H/1mol H)


either method is correct?

[Jorriss]

Neither is correct.

If the question is how many atoms are there in an H2 molecule, it's much simpler.

H2 is two hydrogen atoms bonded together, therefore, H2 is simply 2 hydrogen atoms.

[samiam]

its based on the equation

[Jorriss]

Right, they gave you a chemical equation but if all they asked is, 'so the question is how many hydrogen atoms are there in h2'

The answer isn't based on the equation.

[samiam]

sorry my question was not clear, it was how many hydrogen atoms are in H2 according to the equation above.

than is my answer correct?


my teacher did a similar question where it was the same question but it was how many molecules of h2  are there
all he did was 2 mol h2* Avogadro.

[Jorriss]

Do you have the exact wording of the question because what that means is unclear to me.

did they give you a starting quantity like 'We react 1 mole of hydrogen with...'

[samiam]

Do you have the exact wording of the question because what that means is unclear to me.

did they give you a starting quantity like 'We react 1 mole of hydrogen with...'

" According to the equation given, how many atoms of Hydrogen are there in hydrogen gas"

the question my teacher answered was " Given the equation how many molecules of H2 are there"

[Jorriss]

Yeah, so if that's what was asked, it really is independent of the equation. Hydrogen gas, H2, is made up of 2 hydrogen atoms. That is all.

For the second question, it's not a question you really calculate. There are two molecules, or two moles, of hydrogen gas for every one molecule, or mole of oxygen, for every two molecules, or moles, of water.

[samiam]

Yeah, so if that's what was asked, it really is independent of the equation. Hydrogen gas, H2, is made up of 2 hydrogen atoms. That is all.

For the second question, it's not a question you really calculate. There are two molecules, or two moles, of hydrogen gas for every one molecule, or mole of oxygen, for every two molecules, or moles, of water.

yeah thats what i thought initially. But I don't know why my teacher did it that way.

[Jorriss]

I'm not sure either, it's a strangely worded question for certain.