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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: dyeownsme on December 06, 2004, 02:26:41 PM

Title: Gases: Mass of reactant needed to produce volume of reactant
Post by: dyeownsme on December 06, 2004, 02:26:41 PM

Ethanol burns in air according to this equation:

C2H5OH (L) + O2 (G) ----->  CO2 (G)  +  H20 (L)

And asks calculate the mass of ethanol needed to produce 8.00L of CO2 (g) at 27 degrees C at 1.00 atm

I figured the mass produced but am not sure of method to solve this equation.

I am also confused about finding the Delta H for a reaction with on the formula given...   it is an reaction bettween NaOH adn HCl very basic but im stumped....

Thanks for any help whatsoever

Title: Re:Gases: Mass of reactant needed to produce volume of reactant
Post by: Donaldson Tan on December 06, 2004, 02:36:24 PM

convert 8L of CO2 into number of moles

find the required number of moles of ethanol, then convert to mass.

delta H is amount of energy evolved per mole of limiting reagent.

delta H for neutralisation is change in enthalpy during neutralisation per mole of water formed.

Title: Re:Gases: Mass of reactant needed to produce volume of reactant
Post by: jdurg on December 06, 2004, 03:41:02 PM

There is also a small error in the equation you were given.  Due to the heat of combustion, any water that is formed will be formed as a gas and not as a liquid.  This may have an effect on the calculation since the presence of the gaseous water will alter the overall pressure.  So I would make sure that you should be disregarding water before finishing the problem.