Reaction of 2.0 l of hydrogen gas with 1.0 l of oxygen gas yields 2.0 l of water vapor. all gases are at the same temperature and pressure. show how these data support the idea that oxygen gas is a diatomic molecule. must we consider hydrogen to be a diatomic molecule to explain these results?

Yes

Explanation:

Hello,

Since the gases have intermolecular forces for them to be stable even when they undergo chemical reactions, for stoichiometric analysis they must be diatomic. For the required demonstration, consider that the chemical reaction is stated as:

The properly balanced chemical reaction must be:

Thus, because of the pressure and temperature are the same for all the gases, if you use the ideal gas equation, the volumes are equally related as 2L for hydrogen, 1 L for oxygen and 2 L for steam (water vapor) due to the balancing coefficients in the chemical reaction.

Best regards.

n+h→nh3

we must remember that nitrogen and hydrogen are both diatomic molecules in their standard gas form. this adjusts the equation to

n2+h2→nh3

now we need to adjust coefficients in order to balance the atoms on each side of the equation. currently we have 2 atoms of nitrogen and 2 atoms of hydrogen on the reactant side and 1 atom of nitrogen and 3 atoms of hydrogen on the product side.

we can balance the hydrogens by placing a coefficient of 2 in front of ammonia and a coefficient of 3 in front of the hydrogen.

n2+3h2→2nh3

this gives us 6 hydrogen on each side and coincidentally the nitrogens now equal 2 on each side.