When octane (C8H18) is burned in oxygen, carbon dioxide and water is produced. Write a balanced equation. If 320 grams of octane is burned and 392 grams of water is recovered, what is the percent yield of the experiment.

I think that for setting it up the balanced equation I need to do something along the lines of a combustion reaction (C...+O2 --> Co2 + H2)
I just don't know exactly how to do that.

The formula for Percent yield shouldn't be hard for me to figure out. I just need to know how to set up the balanced equation.

C8H18 + O2 => CO2 + H2O

now just make it balance by adding coefficients

This post was edited by carteblanche on Mar 8 2015 08:20pm

thank you so much!

you pretty much just write out what they gave you.



so octane and oxygen on the left, carbon dioxide and water on the right.

I wasn't in class the day my teacher went over transition/translating whatever that process is.

But balancing is gg for me, too easy, and i have the notes on percent yield somewhere

thanks again dude

This post was edited by Jizzmoe on Mar 8 2015 08:32pm

just to double check, when balanced it would look like:
2C8H18+25O2 ---> 16CO2 + 18H20

correct?

C8H18 + O2 > Co2 + H2O

You have to balance it so there are the same amount of molecules on each side.

2C8H18 + 25O2 > 16Co2 + 18H2O

So, if you have 2 molecules of octane(C8H18), that means you will need 16 atoms of Carbon and 36 atoms of Hydrogen on the other side, that is necessary. All that's left after that is oxygen, and you have an unlimited supply of that(assuming). So if you have 16 atoms of Carbon, that can make 16 molecules of Co2, since it only needs one atom per, which means you will need 32 atoms of oxygen, to complete the molecule, which we will come back to in a second. If you have 36 atoms of Hydrogen, then you can make 18 molecules of H2O, since you need 2 atoms per molecule, but you will also need 18 atoms of oxygen to complete the atom.
So, in total you will need 50 oxygen atoms, this is where we go back to the first side of the equation and plug that in, which gives us 25 molecules of O2. There needs to be 2 molecules of octane because you need an even number of oxygen for the molecule O2, if you only used one molecule of octane, you would need an odd number of O2 to complete the equation, which you cannot do, therefore.. 2 molecules lol.

86.30%

?

When 10.00 grams of Al react with excess H3PO4, 30.0 grams of AlPO4 are produced. What is the percent yield of this reaction?
2Al(s) + 2 H3PO4 --> 2 AlPO4 (aq) + 3H2(g)

What do the letters in the parenthesis stand for?
This is already balanced?

i know how to balance btw Hunter