Could somebody please help me on this gas law question for chem?

4 NH3 + 5 O2 -> 4 NO + 6 H20

4 mol 5 mol 4 mol

Here 5 mol of O2 gives 4 mol of NO

OR 1 mol of NO will be obtained from 5/4 = 1.25 mol O2

I think the question should be "What volume of O2 at 722 mm Hg and 41 degrees celcius is required to synthesize 11.5 mol of NO?"

If such is the case then for the synthesis of 11.5 mol NO we require = 11.5 x 1.25 = 14.375 mol O2

Now using the ideal gas equation PV = nRT

V = nRT/P

Here n = 14.375 mol; R = 0.082 L atm K-1 mol-1; T = 273 + 41 = 314K; P = 722/760 = 0.95 atm

Hence volume of O2, V = 14.375 x 0.082 x 314/0.95 = 389.6 L

find mol NO first, n.NO = m/Mr = 11.5/30 = 23/60 mol, then

4 NH3 + 5 O2 -> 4 NO + 6 H2O

mol O2 = (coeficient O2/ coeficient NO) * n.NO = 5/4 * 23/60 = 23/48 mol

PV =nRT

V= nRT/P (which is given that P= 722 atm, T=41+273= 314 K , n= 23/48 mol, R=0.082 )

V= (23/48 * 0.082 * 314)/722 = 0.017 L

i'm not sure you want to write 722 atm or 722 mmHg , if its 722 mmHg, so its pressure become P= 722/76 = 9.5 atm

so V= (23/48 * 0.082 * 314)/9.5 = 1.3 L

i'm sure i'm doing this right :)

got it>?

resolve the perfect gas regulation for each variable to work out no count number if that's direct or inverse. a) P=nRT/V Inverse because of the fact V is in the denominator. as V will improve P decreases b) V=nRT/P the two in numerator. Direct version with T. As T improve V will improve. c) P= nRT/V Direct version with T. As T will improve, P will improve

Is that supposed to be atm of Hg or mm Hg. I think you need to convert your units of pressure, because your volume of O2 seems a little small.

4 NH3 + 5O2 -------------> 4NO + 6 H2O

-------------5(22.4)----------4(22.4)

for 11.5 l of NO required O2 at STP = 5*22.4* 11.5/4*22.4

= 14.375 l

P1V1/T1 = P2V2/T2

722* V1/314 = 760 * 14.375 / 300

V1 = 760X14.375X314/722X300

= 3430450/216600

V1 = 15.83 L ANSWER