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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Elianna on April 17, 2015, 07:46:37 AM

Title: a combustion problem
Post by: Elianna on April 17, 2015, 07:46:37 AM
A generator gas ( producer gas ) is a type of fuel in the gas phase ( gas that produces thermal energy ) which is produced by the transfer of air or steam through the hot charcoal layer or a layer of another combustible material produced from coal . Such gas has the following composition ( volumetric percentages ) :

 8.0 % CO2 , 23.2 % CO , H2 17.7 % , 1.1 % CH4 , 50% N2 .

How many liters of air ( which is at a temperature of 32 ° C and 4 atmospheres pressure ) are required for complete combustion of 144 liters of gas generators , in the same conditions ? ( Hint: of gases comprising the gaseous fuel , which are the three flammable ? ) Given that the composition of air is 21 % oxygen and the rest nitrogen ( molar percentage ) .
Title: Re: a combustion problem
Post by: Vidya on April 17, 2015, 07:55:12 AM
there are only three flammable gases present
work out the volume of each gas in 144 L of the mixture
write balanced equation and work out the volume of oxygen required for each gas ... get total volume of the oxygen gas --convert that in the moles of Oxygen and then convert it to moles of air and finally volume of air by using ideal gas equation...
Title: Re: a combustion problem
Post by: sjb on April 17, 2015, 07:56:16 AM
A generator gas ( producer gas ) is a type of fuel in the gas phase ( gas that produces thermal energy ) which is produced by the transfer of air or steam through the hot charcoal layer or a layer of another combustible material produced from coal . Such gas has the following composition ( volumetric percentages ) :

 8.0 % CO2 , 23.2 % CO , H2 17.7 % , 1.1 % CH4 , 50% N2 .

How many liters of air ( which is at a temperature of 32 ° C and 4 atmospheres pressure ) are required for complete combustion of 144 liters of gas generators , in the same conditions ? ( Hint: of gases comprising the gaseous fuel , which are the three flammable ? ) Given that the composition of air is 21 % oxygen and the rest nitrogen ( molar percentage ) .

Start by considering the hints. Which of the gases listed are flammable? Can you write balanced equations for their complete combustion?
Title: Re: a combustion problem
Post by: Elianna on April 17, 2015, 08:04:57 AM
Thank you all. I tried approaching it the way you suggested and Im just not sure I got the right answer. The problem is I need to submit it online and I only have one shot at the right answer. I got an answer that just seems too big to me. Any way someone can double check me? It came out to around 2000..
Title: Re: a combustion problem
Post by: Hunter2 on April 17, 2015, 08:22:29 AM
Its to high.  Convert the Units in SI units.

You can calculate rough how much volume CO, H2 and CH4 you have with the Percentage. This is under standard condition.
This gases you have to burn , what are the combustion equations. You can calculate the moles of oxygen what is needed and also the air. This value you have to convert with the ideal gas equation to the given values.
Title: Re: a combustion problem
Post by: sjb on April 17, 2015, 09:36:43 AM
Its to high.  Convert the Units in SI units.

You can calculate rough how much volume CO, H2 and CH4 you have with the Percentage. This is under standard condition.
This gases you have to burn , what are the combustion equations. You can calculate the moles of oxygen what is needed and also the air. This value you have to convert with the ideal gas equation to the given values.

I don't think you have to convert everything all the way to stp for this.
Title: Re: a combustion problem
Post by: Hunter2 on April 17, 2015, 10:03:28 AM
I didnt said that. Only the final value has to be converted.
Title: Re: a combustion problem
Post by: Elianna on April 17, 2015, 10:23:37 AM
Thank you! I'll try it again.
Title: Re: a combustion problem
Post by: Elianna on April 17, 2015, 10:25:07 AM
Although I am not sure how to write the balanced equation for the complete combustion
Title: Re: a combustion problem
Post by: Borek on April 17, 2015, 12:09:59 PM
You should have several separate equations, not one.