8 replies to this topic

[chemtoli]

A gas mixture is composed of:

 

Methane = 80.75 mol%

 

Ethane = 7.45 mol%

 

Propane = 3.25 mol%

 

Butane = 2.31 mol% ,

 

Pentane = 0.24 mol%

 

Nitrogen = 3.05 mol%

 

Carbon dioxide = 2.95 mol% 

 

 

How to convert each component from mole% to mass%?.

[Pilesar]

multiply each component by its molecular weight, then normalize the result to get the component mass fraction.

[breizh]

Hi,

The best way to learn is to perform the task and show us the difficulties if any.

let you start with a basis of 100 moles, and all data related to molecular weight of each component.

Good luck

Breizh 

[chemtoli]

Hi,

The best way to learn is to perform the task and show us the difficulties if any.

let you start with a basis of 100 moles, and all data related to molecular weight of each component.

Good luck

Breizh 

 

 

Hi Breizh, 

 

I need to convert Main Feed Composition from mol% to mass%. 

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Edited by chemtoli, 13 March 2023 - 11:34 AM.

[chemtoli]

multiply each component by its molecular weight, then normalize the result to get the component mass fraction.

 

 

Hi Pilesar, 

 

Could you please explain what does it mean to normalize the results.

[latexman]

Converting a mixture from mole % to mass % is shown in many undergraduate ChE textbooks, like Elementary Principles of Chemical Processes by Felder and Rousseau. That was the textbook used in my first ChE class in University. You should refer back to your first ChE textbooks for help, then, if you have difficulties, show us your work. I doubt one of us is going to do your homework for you.

[Pilesar]

After you multiply mol% by molecular weight for each component, the sum of the component quantities will no longer be 100%. Divide each component quantity by the total sum to find the component fraction on a 100% basis. 

  Are you extremely early in your engineering studies? Chemical engineering education gets more difficult quickly. I do not want to discourage you, but evaluate whether you find it fun and are able to keep up with your fellow students. If you are going to change fields of study, do not wait until you get to the specialty classes.

[breizh]

Hi ,

Consider a mixture of 2 components , N2 and CO2  with Molecular weight 28 and 44 g/mol and 20 % and 80 % mol composition .

Let say the total quantity is 100 moles >>> 20 Moles of N2 and 80 moles of CO2  >>> which means  20*28 = 560 g of N2 and 80*44 = 3520 g of CO2  leading to a total of 4080 g .

Thus % mass N2 = 560 /4080*100 =13.726% and %mas Co2 = 86.274 % 

 

Apply this methodology to your mixture .

 

Breizh 

[SilverShaded]

Don't they teach this in school, for 12 yr olds?