كل مايخص كيمياء 202

[المواعزيه]

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5)-The enthalpy of combustion of acetylene C2H2 is C2H2(g) + (5/2)O2(g) → 2CO2(g) + H2O(l) ∆H°rxn= -1299 kJ calculate the enthalpy of formation of acetylene, given the following enthalpies of formation ∆H°f[CO2(g)] = -393.5 kJ/mol ∆H°f[H2O(l)] = -285.8 kJ/m

a) 227 kJ/mol
b) 227 J/mol
c) -228 kJ/mol
d) 227 J/mo
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8)-Hydrogen peroxide (H2O2) decomposes according to the equation H2O2(l) → H2O(l) + ½O2(g )
From the following data calculate Kp for this reaction at 25°C ∆H° = –98.2 kJ , ∆S° = 70.1 J/K

a) 1020
b) 10.2
c) 20.1
d) 102

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10)-The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide HgO(s) → Hg(l) + ½O2(g) ∆H° = 90.84 kJ
Use the data given below to estimate the temperature at which this reaction will become spontaneous under standard state conditions S°(Hg) = 76.02 J/K• mol , S°(O2) = 205.0 J/K• mol, S°(HgO) = 70.29 J/K• mol

a) 840 K
b) 480 K
c) 840 C°
d) 480 C
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