Identify any statement that is false. A) The entropy of a gas is greater than th
ID: 503192 • Letter: I
Question
Identify any statement that is false. A) The entropy of a gas is greater than the entropy of a liquid. B) Entropy generally increases with increasing molecular size. C) Free atoms have greater entropy than molecules. D) Entropy increases with dissolution. E) For noble gases, entropy increases down the column. Use the standard half-cell potential listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25 degree C. (The equation is balanced.) 3 Cl_2 (g) + 2 Fe (s) rightarrow 6 Cl^- (aq) + 2 Fe^3+ (aq) Cl_2 (g) + 2e^- rightarrow 2 Cl^- (aq) E^0 = +1.36 V Fe^3+ (aq) + 3 e^- rightarrow Fe (s) E^0 = -0.04 V A) +4.16 V B) -1.40 V C) -1.32 V D) +1.32 V E) +1.40 V Which of the following reactions would be the non-spontaneous under standard conditions? A) A + 2 B rightarrow C E^0_cell = +0.98 V B) A + B rightarrow 2 C E^0_cell = -0.030 V C) A + B rightarrow 3 C E^0_cell = +0.15 V D) A + B rightarrow C E^0_cell = +1.22 V E) More information is needed to determine. Calculate delta S degree_rxn for the following reaction. The S degree for each species is shown below the reaction. 4 NH_3 (g) + 5 O_2 (g) rightarrow 4 NO(g) + 6 H_2 O (g) A) +287.4 J/K B) -401.2 J/K C) +160.0 J/K D) -336.6 J/K E) +178.8 J/KExplanation / Answer
1) All the statements are true except
c) Free atoms have greater entropy than molecules
The entropy of atoms lower entropy as compared to molecules due to less number of ways to distribute energy amongst free atoms.
2) E0cell = E0cathode - E0anode
Cathode: where reduction takes place E0cathode = +0.1.36
Anode: where oxidation takes place. E0anode = -0.04 V
E0cell = 0.136 - (-0.04) = +1.40 V
3) The reaction which has negative E0cell will be non spontaneous as DeltaG will be positibe
DeltaG = -nFE0
So answer is
B) A + B --> 2C E0 = -0.030 V
4) DeltaSrxn = Sum of DeltaS products - Sum of DeltaS reactants
Delta Srxn = 4(210.8) + 6(188.8) -[5(205.2) + 4(192.8)] = 1976 - 1797.2 = 178.8 J / K