Briefly describe the Third Law of Thermodynamics. b) Consider the reaction 2X(g)+ O2(g)→3Y(g) carried out at 25°C and 1 atm. Calculate ΔHrxn°, ΔSrxn°, and ΔGrxn° using the following data. Identify whether the reaction is spontaneous or not. (Assume all gases are perfect). Substance DHfo (kJ/mol) So(J/k mol) X (g) -250 250 Y (g) -300 280 O2 (g) 0 205 c) In a reaction, A + B → Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled. Choose the correct rate law for the reaction from below. Explain your answer briefly. Rate = k[A][B] Rate = k [A][B]2 Rate = k [A]2[B] Rate = k [A][B]3 d) One mole of N2(g) occupies 5 L of volume at 300 K in a sealed cylinder. The gas behaves ideally in expanding isothermally to 10 L. Calculate w, ΔE and ΔH if the expansion proceeds (i) reversibly, (ii) irreversibly against an external pressure at 0.2 atm
a) Briefly describe the Third Law of
b) Consider the reaction 2X(g)+ O2(g)→3Y(g) carried out at 25°C and 1 atm. Calculate ΔHrxn°, ΔSrxn°, and ΔGrxn° using the following data. Identify whether the reaction is spontaneous or not. (Assume all gases are perfect).
|
Substance |
DHfo (kJ/mol) |
So(J/k mol) |
|
X (g) |
-250 |
250 |
|
Y (g) |
-300 |
280 |
|
O2 (g) |
0 |
205 |
c) In a reaction, A + B → Product, rate is doubled when the concentration of B is doubled, and rate increases by a factor of 8 when the concentrations of both the reactants (A and B) are doubled. Choose the correct rate law for the reaction from below. Explain your answer briefly.
- Rate = k[A][B]
- Rate = k [A][B]2
- Rate = k [A]2[B]
- Rate = k [A][B]3
d) One mole of N2(g) occupies 5 L of volume at 300 K in a sealed cylinder. The gas behaves ideally in expanding isothermally to 10 L. Calculate w, ΔE and ΔH if the expansion proceeds (i) reversibly, (ii) irreversibly against an external pressure at 0.2 atm.
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