[nlong8]

When 0.150 mole of C3H8O (g) are burned with excess O2 (g) in a constant pressure calorimeter (with a heat capacity of 89.5 kJ/ºC )  to produce CO2 (g) and H2O (l),  the temperature of the calorimeter increased from 21.75ºC to 28.40ºC.  What is DH° for the combustion of 1 mole of C3H8O ?

ok, so this is how i did it...using my logic..

0.150 moles C3H8O/ (28.4-21.75) = 1 mole C3H8O/(t-21.75)
solve for t, t=261.833
261.833-21.75 = 240

240 degrees c (89.5kJ)/1Deg c
 =21480 j or kj or somethin, sigh
pleez help
nate

[nlong8]

why no replies?
is something unclear?

[Rabn]

I think there may be some confusion with what DH° is, I'm going to assume you mean  :delta: H°.  Are you familiar with Hess' Law?

[nlong8]

Yes i am, and that symbol is Delta H.