
#1
Nov2208, 09:10 PM

PF Gold
P: 122

What is the mass of methane (CH_{4}) if it occupies 32.3 L at STP?
We got a whole bunch of these problems on a worksheet with minimal instruction. If somebody could please aid me in solving this one, then I should be able to solve the rest. I assume that I must first find the masses of the individual components... C = 12.0107 * 1 = 12.0107 +H = 1.00794 * 4 = 4.03176  16.0483 Then I honestly don't know what to do... I don't want the answer; I'd just really appreciate if somebody could show me how to do this. I tried searching for a guide online, but none of them really had what I was looking for. Thank you! 



#2
Nov2208, 09:51 PM

HW Helper
P: 2,692

STP means Standard Temperature and Pressure.
Use PV=nRT. 



#3
Nov2308, 04:45 AM

Admin
P: 22,655

jacksonpeeble: you have to know what temperature and pressure your teacher want's you to use as STP, as this thing is not precisly defined. 



#4
Nov2308, 07:45 AM

PF Gold
P: 122

Simple Mole Conversions
1 mole = 22.4 L at STP according to my teacher.
What do I do with that equation? I assume that it is the same as (Pressure x Volume)/(Temperature x Moles) = R, but how is this applied? Thanks for the help so far, though! 



#5
Nov2308, 07:59 AM

P: 5

and then let 32.3 L = x mol at STP. you can get x. do you know how to do now? (forget that equation...for this problem, it is useless.)




#6
Nov2308, 08:29 AM

Admin
P: 22,655

What is molar mass of methane? While PV=NRT is the general method, that will give exactly the same results if applied correctly, you can solve the question using just the information quoted above. 



#7
Nov2308, 08:30 PM

PF Gold
P: 122

Ah, so it's essentially just a ratio?
So it would be 32.3/22.4 = 1.44 Moles? 


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