Please answer the questions in the image Which one of the following processes sh

Question

Please answer the questions in the image

Which one of the following processes shows a decrease in entropy of the system? 2 NO(g) + O2(g) rightarrow 2 NO2 (g) COCI2 (g) rightarrow CO(g) + Cl2 (g) CH3OH(l) rightarrow CO(g) + 2H2 (g) NaCIO3 (s) rightarrow Na+(aq) + ClO3-(aq) None of the above will show a decrease in entropy. Consider a reaction that has a positive AH and a positive AS. Which one of the following is TRUE? This reaction will be spontaneous only at low temperatures. This reaction will be spontaneous at all temperatures. This reaction will be nonspontaneous at all temperatures. This reaction will be spontaneous only at high temperatures. Estimate delta G degree rxn for the following reaction at 449.0 K. rightarrow CH2O(g) + 2 H2(g) rightarrow CH4(g) + H2O(g) Delta H degree = -94.9 kJ; Delta S degree = - 224.2 J/K +5.8 kJ +12.9 kJ -101kJ +2.4kJ -4.2kJ Determine the redox reaction represented by the following cell notation. Mg(s) | Mg2+(aq) || Cu2+(aq) | Cu(s) Cu(s) + Mg 2+(aq) rightarrow Mg

Explanation / Answer

1) Entropy, or disorderness of the system decreases due to decrease in no. of moles in product..

so, a) 2NO2 + O2 -> 2NO2

2) Delta G = Delta H - t*Delta S

The reaction is spontaneous if Delta G is negative,so here

=> here Delta G < 0 only for High Temperatures

So, (a)

3) Delta G = -94900 - 449*(-224.2) = 5765.8 J = +5.8 KJ

4)

Mg(s) -> Mg(s) + 2e-

and Cu+2(aq) + 2e- -> Cu(s)

Adding these two reactions, we het Redox as Mg(s) + Cu+2(aq) -> Cu(s) + Mg+2(aq)

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