Enthalpy Help! PLEASE!
How would I answer this question?
Isooctane (C8H18) is a type of petrol fuel.
When it is burnt it has an enthalpy change of ' minus 47.8 KJ/g '.
Isooctane is liquid at room temperature with a density of '0.692 g/cm3'
Find the heat energy released in 'KJ' when '1.0 dm3' of isooctane (C8H18) burns in excess oxygen.
I'm absolutely confused in where to even start. I figured out that the mass of isooctane (C8H18) must be '692 g' since volume is '1.0 dm3' and density is '0.692 g/cm3'.
So that means that '0.692 * 1000' gives '692 grams' of isooctane.
But what do I do next???
Do I use the formula 'enthalpy = q / moles' and rearrange to get 'q'....
Someone help I really don't know the answer!
Isooctane (C8H18) is a type of petrol fuel.
When it is burnt it has an enthalpy change of ' minus 47.8 KJ/g '.
Isooctane is liquid at room temperature with a density of '0.692 g/cm3'
Find the heat energy released in 'KJ' when '1.0 dm3' of isooctane (C8H18) burns in excess oxygen.
I'm absolutely confused in where to even start. I figured out that the mass of isooctane (C8H18) must be '692 g' since volume is '1.0 dm3' and density is '0.692 g/cm3'.
So that means that '0.692 * 1000' gives '692 grams' of isooctane.
But what do I do next???
Do I use the formula 'enthalpy = q / moles' and rearrange to get 'q'....
Someone help I really don't know the answer!
well I think you are making it more complicated than it needs to be. You said that need to work out the heat energy released for complete combustion of 692grams of isocotane.
You also told me that it's enthalpy change is -47.8kJ per gram.
So all you have to do is -47.8 * 692 = 33077.6kJ
The answer is that 33077.6kJ heat energy is released from the complete combustion of 1 dm3 of isooctane.
You also told me that it's enthalpy change is -47.8kJ per gram.
So all you have to do is -47.8 * 692 = 33077.6kJ
The answer is that 33077.6kJ heat energy is released from the complete combustion of 1 dm3 of isooctane.
(edited 6 years ago)
Original post by YouMadBro!
well I think you are making it more complicated than it needs to be. You said that need to work out the heat energy released for complete combustion of 692grams of isocotane.
You also told me that it's enthalpy change is -47.8kJ per gram.
So all you have to do is -47.8 * 692 = 33077.6kJ
The answer is that 33077.6kJ heat energy is released from the complete combustion of 1 dm3 of isooctane.
You also told me that it's enthalpy change is -47.8kJ per gram.
So all you have to do is -47.8 * 692 = 33077.6kJ
The answer is that 33077.6kJ heat energy is released from the complete combustion of 1 dm3 of isooctane.
Oh wow... Yep that makes sense. I guess I just overcomplicated it since of how overwhelmed I got from all the wording in the question.
Cheers mate!
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