Iso-octane is used in gasoline/automobile engineering as a standard, with an "octane rating" of 100. The standard molar enthalpy of formation of iso-octane C8H18(l) is -223.8 kJ/mol. For the balanced reaction equation of octane use: C8H18(l) + 12.5O2 --> 8CO2 + 9H2O.

Octane is a liquid, but all the other chemicals in this reaction are gases. What is the enthalpy change of this reaction in kJ/mol?

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

it should be all of them because it asks if you included all of those in your answer

explanation:

a is the answer to this question

explanation: