Need help with chemistry homework ASAP pleaseee!!!!?

M

M B

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Okay here are the problems I couldn't solve, I need the answers ASAP please, and I will award the ten points to whoever gives me the first correct answer thanks!

1) Ethylene glycol, HOCH2CH2OH, is used as antifreeze. It is produced from ethylene oxide, C2H4O, by the following reaction.

C2H4O(g) + H2O(l) → HOCH2CH2OH(l)
Use Hess's law to obtain the enthalpy change for this reaction from the following enthalpy changes.

2 C2H4O(g) + 5 O2(g) → 4 CO2(g) + 4 H2O(l) ΔH = −2612.2 kJ
HOCH2CH2OH(l) + 5/2 O2(g) → 2 CO2(g) + 3 H2O(l) ΔH = −1189.8 kJ


2) The thermite reaction is a very exothermic reaction; it has been used to produce liquid iron for welding. A mixture of 2 mol of powdered aluminum metal and 1 mol of iron(III) oxide yields liquid iron and solid aluminum oxide. How many grams of the mixture are needed to produce 313 kJ of heat? See Appendix C for data.
 
Question 1:
-- From: HOCH2CH2OH(l) + 5/2 O2(g) → 2 CO2(g) + 3 H2O(l) ΔH = −1189.8 kJ,
We can obtain: 2 CO2(g) + 3 H2O(l) → HOCH2CH2OH(l) + 5/2 O2(g) ΔH = +1189.8 kJ,
Thus: 4 CO2(g) + 6 H2O(l) → 2HOCH2CH2OH(l) + 5 O2(g) ΔH = +2379.6 kJ.
-- Add the LHSs and RHSs of the following:
2 C2H4O(g) + 5 O2(g) → 4 CO2(g) + 4 H2O(l) ΔH = −2612.2 kJ,
4 CO2(g) + 6 H2O(l) → 2HOCH2CH2OH(l) + 5 O2(g) ΔH = +2379.6 kJ,
and cancel out 5 O2s and 4 CO2s and 4 H2Os, we obtain:
2 C2H4O(g) + 2 H2O → 2HOCH2CH2OH(l) ΔH = -232.6 kJ.
-- Thus: C2H4O(g) + H2O(l) → HOCH2CH2OH(l) ΔH = -116.3 kJ

Question 2:
-- First you find the enthalpy change for 2 Al + Fe2O3 → 2 Fe + Al2O3, let it be X,
-- Then you the number of moles of Al required is 2 * 313 / X, for Fe2O3 it is 313 / X,
-- Then you convert the number of moles of the two respective substances, using the formula:
mass = molar mass * number of moles.
-- Add the masses of the two respective substances up to finish the question! :)
-- By the way I did not find your appendix.
 
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