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Convert Kp to Kc?by needphyshelp
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#1
Oct1208, 12:31 AM

P: 21

1. The problem statement, all variables and given/known data
At 25°C, Kp = 1x10^{31} for the reaction below. N2(g) + O2(g) <> 2 NO(g) (a) Calculate the concentration of NO (in molecules/cm3) that can exist in equilibrium in air at 25°C. In air PN2 = 0.8 atm and PO2 = 0.2 atm. 2. Relevant equations ?? 3. The attempt at a solution I have calculated the partial pressure of NO to be 1.26x10[SUP]16[SUP] but I do not know how to convert to Kp from this. Any help would be greatly appreciated! 


#2
Oct1208, 03:11 AM

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#3
Oct1208, 09:32 AM

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First of all, you do not need to convert Kp to Kc.
Hint: Ideal gas equation. 


#4
Oct1208, 12:29 PM

P: 21

Convert Kp to Kc?
I'm sorry  I am trying to convert partial pressure to concentration.
Using the Ideal gas equation, PV=nRT, do I use n=2, solve for volume, and then convert to molecules per cm^3? 


#5
Oct1208, 03:45 PM

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Hint: You can find the molecules per cc if you first find the moles per unit volume, i.e., n/V 


#6
Oct1308, 12:23 PM

P: 21

I still am not getting the correct answer. I don't know what I'm missing.
PV=nRT = 1.3E16(V)=n(.08206)(298) so moles/L = 5.32E18. I then converted it to moles/cm3 by dividing by 1000, which gave me 5.32E21 then multiplied by Avogadro's number to get 3203.7 molecules/cm3. I also tried converting atmospheres to bars and using the gas constant 83.145 so that my answer would be in moles/cm3 and then converting from there, but that was not correct either. Can you tell me what I am doing wrong? 


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