Acetic acid. HC_2H_3O_2, is contained in vinegar. What is the enthalpy change (A
ID: 1015111 • Letter: A
Question
Acetic acid. HC_2H_3O_2, is contained in vinegar. What is the enthalpy change (AH) for the process in which acetic acid is formed from its elements? 2C(Graphite) + 2H_2(g) + O2(g) rightarrow HC_2HC_3O_2(I) delta H = ? Use the following thermo chemical reactions: HC_2H_3O_2(I) + 2O_2(g) rightarrow 2CO_2(g) + 2H_2)(I) delta H = -871 KJ C(Graphite) + O_2(g) rightarrow CO_2(g) delta H = -394 KJ 2H_2(g) + O_2(g) rightarrow 2H_2(I) delta H = -572 KJ 1754 KJ 101.2 KJ 489 KJ -1754 KJ -489 KJ The cooling effect of alcohol on the skin is due to its evaporation. What is the heat of vaporization (delta H) of ethyl alcohol. C_2H_5OH? C_2H_5OH(I) rightarrow C_2H_5OH(g) delta H = ? Use the following Enthalpies of Formation. delta H_f[C_2H_5OH(I)] = -277.6 KJ/mol & delta H_f[C_2H_5OH(g)] = -235.4 KJ/mol 42.2 KJ 0.0237 KJ 513 KJ -0.0237 KJ -42.2 KJ What is the enthalpy change (AH) for the following reaction? 2H_2S(g) + 3O_2(g) rightarrow 2H_2O(I) + 2SO_2(g) delta H = ? Use the following Enthalpies of Formation: delta H_f[H_2S(g)] = -20.15 KJ/mol, delta H_f[H_2O(I)] = -285.8 KJ/mol, & delta H_f[SO_2(g)] = -296.4 KJ/mol -602.4 KJ 1124.1 KJ 1204.7 KJ -1124.1 KJ -1204.7 KJExplanation / Answer
From the given quations,
2 Co2 (g) + 2 H2O (l) ------> HC2H3O2(l) + O2(g) ; dH = 871 kj
2 C (Graphite) + 2 O2 (g) -----> 2 CO2 (g) ; dH = 2*(-394) = -788 kj
2H2 (g) + O2 (g) -----> 2 H2O(l) ; dH = -572 kj
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2 C (Graphite) + O2(g) + 2 H2(g) -----> HC2H3O2(l) ; dH = -489 kJ
answer : e
C2H5OH(l) ----> C2H5OH(g) ; dH = ?
dH rxn = dH products - dH reactants
dH rxn = -235.4 -(-277.6)
dH rxn = 42.2 kj
Answer ; A
2 H2S(g) + 3O2(g) -----> 2H2O(l) + 2SO2(g) ; dH = ?
dH rxn = dH products - dH reactants
dH rxn = 2*(-296.4) +2*(-285.8)-(2*-20.15 + 3*0)
dH rxn = -1124.1 kj
Answer : d