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Someone who is amazing at chemistry please help!

Nitrogen reacts with hydrogen to form ammonia.
N2 (g) + 3H 2(g) --> 2NH3(g)
(i) Calculate the minimum volume of nitrogen, in dm3, required to react
completely with 1000 dm3 of hydrogen.
All volumes are measured at the same temperature and pressure.

I've been stuck on this question for about 30 minutes and I keep getting the answer 2333 even though the answer is 333. I don't really need to know the answer I need to know how to work it out. Please help and thanks!
Reply 1
Avatar for HuXinMei
HuXinMei
6
1000/22.7 = moles of hydrogen = 44.05
44.05/3 = moles of nitrogen = 14.68
14.68*22.7 = volume of nitrogen = 333dm3
Or you could just do 1000/3 = 333 dm3.
Original post by HuXinMei
1000/22.7 = moles of hydrogen = 44.05
44.05/3 = moles of nitrogen = 14.68
14.68*22.7 = volume of nitrogen = 333dm3

Thank you so much for this. However I believe the bit I'm stuck on is how you got the Mr. I thought the Mr for hydrogen was 1 and for nitrogen 14?
Reply 4
Avatar for HuXinMei
HuXinMei
6
Original post by Kingjaxter
Thank you so much for this. However I believe the bit I'm stuck on is how you got the Mr. I thought the Mr for hydrogen was 1 and for nitrogen 14?

I think you are confused, this questions does not include any Mr ( molar mass ) calculations. The long way to find the answer is to use the equation Moles = volume in dm3 divided by 22.7. Instead of this you could just divide 1000 by 3. Look up the equation and it will help you understand.
Reply 5
Avatar for scimus63
scimus63
9
Equal volumes of any gas contain the same number of particles at any given temperature and pressure (Avogadro’s Law). So 10000dm3 of hydrogen or 1000dm3 of nitrogen will contain the same number of particles, however you need the volumes to be in the ratio of 3:1. from the equation, so you need 10000/3 = 333 litres or dm3 of nitrogen.
Original post by scimus63
Equal volumes of any gas contain the same number of particles at any given temperature and pressure (Avogadro’s Law). So 10000dm3 of hydrogen or 1000dm3 of nitrogen will contain the same number of particles, however you need the volumes to be in the ratio of 3:1. from the equation, so you need 10000/3 = 333 litres or dm3 of nitrogen.

Thank you, I understood this. I thought it was a question about moles so I instantly started trying to use molar mass. Now I understand it was about ratios! Thanks again, this really helped!

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