# chemistry

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the thermochemical equation for th edissocation of hydrogen gas into atoms may be written :

h2-> 2H delta H 1824.2

what is the ration of the energy yield on combustion of hydrogen atoms to steam to yield ion combustion of an equal mass of hydrogen molecules to steam given

2H2(g) = O2 (g) -> 2h20 (g) delta H = -2023.7 kj

• chemistry -

I know you want a ratio but I don't know what ratio you want? What is "to yield ion combustion of....."

• chemistry -

excatly, im just as confused. I tried to email him, no reply.

The problem says what is the ratio of energy yield on combustion of hydrogen atoms to steam to the yield on combustion of an equal mass of hydrogen molecules to steam given.

what am i missing

• chemistry -

I'm still confused but not as much. Compare the two parts of your post, take out the i typo on ion for on and add in a word or two you omitted and it makes a little more sense. Do you suppose the prof means this?
The dissociated of H2 into atoms is done by adding 1824.2 J. So if we start with H atoms and they combine to form H2 first before combusting we should get an additional 1824.2 OUT (as a - sign). So we would get 2*2023.7 (4g H2) for 2 mols H2 and we would get 4047.4 + 2*1824.2 (4 gH atoms) if we started with H atoms? So the ratio is
atoms/molecules = ? Looks like almost double. Let me know how it turns out.

• chemistry -

Dr.Bob222 can you work this problem out fully. I don't understand at all.