I\'m not sure how to set this one up. I can\'t find an example in the textbook,
ID: 782455 • Letter: I
Question
I'm not sure how to set this one up. I can't find an example in the textbook, either.
Octane (C8H18) is a component of gasoline that burns as follows:
C8H18(l) + 4O2 ---> 3CO2(g) + 3 H2O(g) %u0394H= -1790kJ
Wht mass of Octane (in g) is required to produce 2,550 kJ of heat? M.M. octane 114g/mole
I would really like to understand how to set that up, I'm really at a loss.
The second question I got an answer for, but I feel like i'm missing something. If it's incorrect, could you explain to me what I did wrong, or what step I missed?
What is the energy of the photons in kilojoules per mole for a wave with a frequency of 3.79 x 10^11 sec-1. (calculate energy per photon, then convert to moles using avogadro's number to get moles.)
E = (3.00 x 10^8 m/sec) (3.79 x 10^11 sec-1)
E= 1.14 x 10^20 J
x = (1.14 x10^20 J/photon) ( 6.022 x 10^23 photon mol)
x = 6.87 kJ/mol x 10^40
Did I do that correctly? If I missed something, could you please explain it to me?
Thanks in advance for helping me with both of these problems
Explanation / Answer
Combustion is essentially the exothermic reaction of a substance with an oxidant, most often oxygen.
When involving hydrocarbons or organic compounds consisting only of C, H and O, CO2 and H2O are produced
1. 2Ba(s) + O2(g) --> 2BaO(s)
2. 4B(s) +3O2(g) --> 2B2O3(s)
3. C3H6O(l) + 4O2(g) --> 3CO2(g) + 3H2O(l)
4. 2C8H18(l) + 25O2(g) --> 16CO2(g) + 18H2O(l)