AS question help Watch

Inertia
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1a) Calculate the enthalpy change when 1.0g of hydrogen burns in oxygen.

I got -286kJmol^-1, the same as the standard enthalpy change of formation of water. Is this right? Because it's the same reaction right?

b) What is the standard enthalpy change for the following reaction?

h2O (l) -----> H2(g) + 1/2O2(g)

I put 286kJmol-1 for this one, as is it not the reverse of the formation of water, and so it follows that the enthalpy change will have the reverse sign?

Anyone that could tell me if i'm right or not on these questions would be a great help!
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EierVonSatan
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looks fine :yy:
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Mariia...
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omdz how did u work that out?,......im not sayin itz wrong or right but im jus confused on how u worked it out....i took chem too and enthalpy changes is probz my worst unit of all.......any help on the calculations would be veryyyyy helpful indeed!
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EierVonSatan
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(Original post by Mariia...)
omdz how did u work that out?,......im not sayin itz wrong or right but im jus confused on how u worked it out....i took chem too and enthalpy changes is probz my worst unit of all.......any help on the calculations would be veryyyyy helpful indeed!
There was no calculation done really, they were given the value for the standard enthalpy change of formation of water and so they just reversed the sign.

PS please don't use text speak on the forum
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Lizzity
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I know this is 6 years to late but shouldn't it be a negative value as it is combustion reaction??
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