Chemical Engineering 1) Dry analysis of the liquid in a tank shows that it conta

Question

Chemical Engineering

1) Dry analysis of the liquid in a tank shows that it contains 60 weight percent methanol and 40 weight percent ethanol. An analysis for water shows that the mixture contains 0.200 moles water per mole of methanol. Calculate the composition of the mixture in mole percent?

2) A Gaseous mixture of CO, CO2,CH4, and N2 is analyzed with a gas chromatograph. The output appears as peak on a strip chart recorder and the areas underr the peaks are proportional of the number of moles of each substance. The following outputs were obtained:

CO Area= 40, CH4 Area=25, CO2 Area=80

Although the gas chromatograph did not analyze for N2 another analysis showed that there were 5 moles of N2 per mole of CH4. Calculate the mole fractions of the four species in the gas and the average molecular weight of the mixture?

Explanation / Answer

There are multiple questions here. I am allowed to answer only 1 at a time. So I will answer question1 for you.
Let there be 100 mol is all.
Let number of moles of methanol be x
Then moles of water = 0.2x
Molar mass of Methanol (CH3OH) = 12+1*4+16 = 32 gm
Mass of methanol = number of moles * molarmass = 32x gm
Mass of ethnaol = (40/60) * 32x
     =21.33 x
Molar mass of Ethanol (C2H5OH) = 2*12+1*6+16 = 46 gm
Number of moles of ethanol = 21.33x/46

Total number of moles = 100
x + 0.2x + 21.33x/46 = 100
46 x + 9.2 x + 21.33 x = 4600
76.53x = 4600
x = 60
Number of moles of methnaol = 60
Of water =0.2*60 = 12
of ethanol = 100-60-12 = 28
In mole percent answers are:
methnaol = 60 %
water = 12 %
Ethanol = 28 %

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