Question

Which one of the following is NOT true? If Ано, =-115 kJ and as rxn -- +263 J/K, then ASuniv> 0 at all temperatures rxn The following reaction 2 NO2(g) → 2 NO(g) + O2(g), Ahº, is not spontaneous at any temperature rxn = +113.5 kJ, The following reaction • 2 H2S(g) → S2(g) + 2 H2(g) Ahº, rxn = +169.8 kJ has a AS surrof - 570 J/K at 298 K For the following reaction 2CO(g) + O2(e) → 2C02(x) + 4 H20(8), AH°rxn - -566 kJ, Asuniv is positive at low temperature but negative at high temperature

Answer 1

= ran If AH = -115 kJ and ASPX +263, then ASuniv> 0 at all temperatures. True. -TASuniv = AHORA - TASO So, if Ahorn < 0 and AS en > 0, the term -TASuniv will be negative at all temperatures so that, AS univ> 0 at all temperatures. The following reaction, 2 NO2 (g) → 2 NO (g) + O2 (g) 47 xn = + 113.5 kJ is not spontaneous at any temperature. False. AG x = AH xn – TAS X The ASPXn is positive because there are more molecules of gases in the product side than in the reactant side. So,|| if AH x > 0 and AS xn > 0, AG xn will be positive to low temperatures, and the reaction will be non-spontaneous. The following reaction, 2 H2S (g) → S2(g) + 2 H2(g) (H xn = + 169.8 kJ has a ASgurr of -570 J/K at 298 K. True. AHPAN AS surr т ASgurr + 169.8 kJ = 0.570 kJ = 570 298 K

The following reaction, 2 CO (g) + O2 (g) → 2 CO2 (g) + 4H20 (9) AH X = - 566 kJ AS univ is positive at low temperature but negative at high temperature. False. The Aspxn is positive because there are more molecules of gases in the product side than in the reactant side. So, -TAS univ = AH, xn - TASPXn So, if AH xn <0 and Aspxn > 0, the term -TAS univ will be negative at all temperatures so that, AS univ> 0 at all temperatures.