# A sample of gas contains 0.1900 mol of CH4(g) and 0.3800 mol of O2(g) and occupi

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A sample of gas contains 0.1900 mol of CH4(g) and 0.3800 mol of O2(g) and occupies a volume of 30.6 L. The following reaction takes place:

CH4(g) + 2O2(g)CO2(g) + 2H2O(g)

Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant.
May 28th, 2015

(no. of moles)/Volume = (no. of moles at S.T.P.)/(Volume at S.T.P.)

(.1900+.3800)/30.6=(n)(v)......................................................

May 28th, 2015

May 28th, 2015

May 28th, 2015

(.5700)/30.6=(2)v

ans=47.5

May 28th, 2015

Avogadro's Law says that equal volumes of gases at the same temperature and pressure contain the same number of molecules (or moles). Mathematically this means that at a given temperature and pressure, the volume of a gas sample is directly proportional to the number of moles of gas in the sample:

V = constant  n

or

 V1 = V2 = constant n1 n2

From the stoichiometry of the balanced equation, it can be seen that the0.1900 mol CH4(g) and the 0.3800 mol O2(g) are present in amounts that react completely:

CH4(g) + 2O2(g)CO2(g) + 2H2O(g)

 0.1900 mol CH4(g) [img src="http://cxp.cengage.com/contentservice/assets/T=1432666732132/owms01h/mediaarchives/GenChem/Image/times14-3.gif"> 2 mol O2(g) =  0.3800 mol O2(g) 1 mol CH4(g)

Similarly, the balanced equation shows the amounts of products that form:

 0.1900 mol CH4(g) [img src="http://cxp.cengage.com/contentservice/assets/T=1432666732132/owms01h/mediaarchives/GenChem/Image/times14-3.gif"> 1 mol CO2(g) =  0.1900 mol CO2(g) 1 mol CH4(g)

 0.1900 mol CH4(g) [img src="http://cxp.cengage.com/contentservice/assets/T=1432666732132/owms01h/mediaarchives/GenChem/Image/times14-3.gif"> 2 mol H2O(g) =  0.3800 mol H2O(g) 1 mol CH4(g)

The intial and final volumes are directly proportional to the numbers of moles:

n1 = 0.1900 mol + 0.3800 mol = 0.5700 mol
V1 = 30.6 L
n2 = 0.1900 mol + 0.3800 mol = 0.5700 mol
V2 = ?

 V2 = V1[img src="http://cxp.cengage.com/contentservice/assets/T=1432666732132/owms01h/mediaarchives/GenChem/Image/times14-3.gif"> n2 (30.6 L)(0.5700 mol) = 30.6 L n1 0.5700 mol

May 28th, 2015

it was 30.6 !

May 28th, 2015

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May 28th, 2015
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May 28th, 2015
Nov 18th, 2017
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