reacting gas question

im stuck on reacting gas volumes, is the answer to this question 8 dm3 as the final volume????

in 4 dm3 of hydrogen sulphide is burned in 10 dm3 of oxygen what is the final volume of the mixture (give volume of each gas at the end)?
2 H2S(g) + 3 O2(g) ------> 2 H2O (g) + 2 SO2(g)

Reply 1

Methene

Don't forget that the oxygen is in excess, so you'll still have some of that left over which will contribute to the final volume.

Reply 2

sg.0

Original post by Methene

Don't forget that the oxygen is in excess, so you'll still have some of that left over which will contribute to the final volume.

oh yeh that makes sense. to get the volume of oxygen would I just minus 4 dm3 off of 10 dm3 to get 6 then just add that to the final volume to get me a final volume of 14 dm3 ?

Reply 3

Methene

Original post by sg.0

oh yeh that makes sense. to get the volume of oxygen would I just minus 4 dm3 off of 10 dm3 to get 6 then just add that to the final volume to get me a final volume of 14 dm3 ?

You would have to consider the stoichiometry - so 2 moles of H2S reacts with 3 moles of O2.

With those proportions in mind, how much O2 would react with 4dm3 of H2S? And then how much O2 would be left? :smile: