ATAR Notes: Forum

VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: hardworker on May 29, 2013, 08:42:59 pm

Title: Really hard neap chemistry question
Post by: hardworker on May 29, 2013, 08:42:59 pm

Can someone please help me with this question

An unknown organic compound was analysed to determine its identity. The compound contains Carbon, Hydrogen, and Oxygen and does not contain any carbon to carbon double bond. When completely oxidized in air the 8.20 gram compound produces 8.19 gram of water and 20.2 gram of carbon dioxide.

Q- Based on the mass of water produced via the oxidation , calculate the mass of Hydrogen in the 8.20 gram sample of the compound.

Please help me i feel so rubbish since i cant even answer this question   :'(

Title: Re: Really hard neap chemistry question
Post by: Jeggz on May 29, 2013, 09:48:13 pm

So I'm not sure if what I did is correct, but this is what I did. We know that the mass of water is 8.20 grams, hence we can go about finding the moles of water, and then the moles of hydrogen.








moles

From here we can figure out the moles of Hydrogen
And hence the mass of Hydrogen is going to be grams as well. Hence we can say that there's 0.91 grams of Hydrogen in the original organic compound because in the combustion reaction, all the Hydrogen from the unknown organic compound is only converted to water. I hope that's right?  :)