Use the values of bond enthaipies given in Section 11 of the IB Chemistry data booklet. 1. All hydrocarbons burn according to the following equation (the state of the hydrocarbon, C. H., at standard
conditions varies according to its mass and structure):
C. H, + (x + 4y)O(g) 4XCO(g) + 2yHẠO(1)
Explain, in terms of bond enthalpies, why the combustion of all hydrocarbons is exothermic.

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.