Sciencemadness Discussion Board

Help with Chemistry

DrgnAngel - 27-9-2004 at 09:22

What mass of hydrogen, in grams, is needed to react completely with 892 g of N2?

N2 + H2 -----> NH3

vulture - 27-9-2004 at 10:02

1) Pick an appropriate topic title. Have a bit of mercy with people that are using the searchengine to find threads.
2) This is an extremely basic question and you should be ashamed for asking it. We're www.sciencemadness.org and www.I-am-too-lazy-to-solve-my-homework.com

DrgnAngel - 27-9-2004 at 10:05

Yes, it might be a basic question for you, but I am having problems solving it. Yes I have tried, and I just don't understand how to solve it.

DrgnAngel - 27-9-2004 at 10:11

Also, I'm not too lazy to do my work. I would rather have someone help me out on how to solve it then just solve it for me. I would like to learn on how to solve it.

JohnWW - 27-9-2004 at 10:17

Learn your atomic weights. These are given in various periodic tables of the elements, which are available on the internet, as well as many textbooks and handbooks. Then you will be able to work out the problem.

John W.

Your own fault...

vulture - 27-9-2004 at 10:23

If you would have provided a pathway and then indicated where exactly you got stuck I wouldn't have to make such a comment...

BTW, use the edit button instead of doubleposting.

thunderfvck - 27-9-2004 at 11:29

So pathetically easy.

Moles (mol) = mass (g) / molar mass (g/mol)

First order of business is to balance the equation. Make it so you have equal numbers of elements on both sides.

Then find out how many moles you have with that number and see how many moles of other stuff you'll need.

Then shake your head in shame, because this kind of question is very easy. Any simple search on stoichiometry (sp) will give you all you need to know.

DrgnAngel - 27-9-2004 at 12:16

Like I said before this type of question might be easy for you, but not me. I'm just beginning to learn chemistry, so it is a harder question for me.
I'll show you how I'm working it out and I would apperciate it if someone would help me out and tell me what I'm doing wrong.

N2 + 3H2 ---> 2NH2

Atomic mass of N2 = 28.01345
Atomic mass of 3H2 = 6.04764

?mol N2= 892 g N2 * 1 mol N2/28.01345 = .0314052 mol N2

.0314052 mol N2* 1 mol 3H2/1 mol N2 = .0314052 mol 3H2

.0314052*6.04764= .189927

vulture - 27-9-2004 at 13:39

Your math is wrong.

Multiplication with 1/28 is the same as dividing through 28....

DrgnAngel - 27-9-2004 at 14:29

thank you.....so i was just making a stupid mistake..my fault


but I do have another question

what mass of quicklime (calcuim oxide), is kg, can be made when 4.72x10^9 g of limestone (calcuim carbonate) is decomposed by heating?

CaCO3 ----> CaO + CO2


I'm not sure on how to start this, so any help would be appreciated.

[Edited on 27-9-2004 by DrgnAngel]

vulture - 28-9-2004 at 09:53

I'm getting very sceptical about this, because it seems you haven't learned much from the previous excercise it seems....

Anyways, convert it all to moles and you're done.

thunderfvck - 28-9-2004 at 09:55

Sorry for being rude earlier, butn this kind of question is very, very, VERY easy...

Don't even bother asking us to help you, search for high school chemistry or something. They will tell you how to do the problem step by step. It shouldn't be hard to understand.

After doing that, if you still have trouble, I guess you coukld come back. But try learning it yourself first! It's not hard at all!