Consider the following reaction: CH3OH(g) --> HCHO(g) + H2(g); DHo = 85 kJ (2) Which of the following statements is TRUE for this reaction when carried out under standard condition? (A) This reaction is spontaneous at all temperatures; (B) This reaction is not spontaneous at any temperature. (C) This reaction is spontaneous at high temperatures, but not at low temperatures; (D) This reaction is spontaneous at low temperatures, but not at high temperatures;

1. Which of the following processes are spontaneous: spreading of a bad odour through a room; separating a mixture of O2 and N2 into two separate samples, one that is pure H2 and one that is pure N2; the reaction of sodium metal with oxygen gas to form a metal oxide; (a) (b)

For a particular reaction, ΔH = -32 kJ and ΔS = -98 J/K.Assume that ΔH and ΔS do not vary with temperature.(a) At what temperature will the reaction have ΔG = 0?(b) If T is increased from that in part (a), will the reactionbe spontaneous or nonspontaneous?

11) Why can endothermic reactions be spontaneous?

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide: HgO(s) → Hg() + 1/2O2(g), AH = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions. S'(Hg) = 76.02 J/K mol S(O2) = 205.0 J/K mol C S(HgO) = 70.29 J/K mol 11

5-For the reaction, A+B C, AH-+30 kJ; AS°=+50 J/K.Therefore the reaction is: (a) spontaneous at all temperatures. (b) nonspontaneous at all temperatures. (d) irreversible at all temperatures (c) reversible at all temperatures 6- How much heat is necessary to convert 2mol of water at( 50°C) to steam at 150°C?The molar heat capacity of liquid water and steam are 75.3 J/mol. K and 36.4 J/mol. K respectively. The heat of vaporization 40.7 KJ/mol. a-81400J 7- From the reactions: b-82.337KJ c-753J d-3641 e- none of them Cgraphia +2H2(g) → CHA(R) AH = -79.9KJ C(graphia + 2Cl2(g) → CCla AH = -139KJ H 20 + Cl₂00) → HCL) AH-92.3KJ 202) calculate AH, for the reaction CH ACE +4Cl2) a- (-615.1KJ) c-(-428.3KJ) 4HCI+CCI b-(-311.2KJ) d- none of them

Determine Δngasfor each of the following reactions:

Given the below thermodynamic data, calculate ΔΔH for the reaction CH4 (g) + NH3 (g) ⟶⟶ HCN (g) + 3 H2 (g):    N2 (g) + 3 H2 (g) ⟶⟶ 2 NH3 (g)                                 ΔΔH = -85.6 kJ    C (s) + 2 H2 (g) ⟶⟶ CH4 (g)                                      ΔΔH = -75.2 kJ    H2 (g) + 2 C (s) + N2 (g) ⟶⟶ 2 HCN (g)                  ΔΔH = +271.4 kJ

Consider the following reaction; A(g) + B(g) → c(s) + D(g); AH = 159.1 kJ; AG = 164.1kJ at 298 K %3D The reaction is spontaneous at relatively high temperatures only The reaction is spontaneous at all temperatures The reaction is nonspontaneous at all temperatures. The reaction is at equilibrium at 298 K The reaction is spontaneous at relatively low temperatures only

17.28 From each equation and standard enthalpy, predict whether the reaction will be spontaneous at all temperatures, spontaneous at low temperatures but nonspontaneous at high temperatures, nonspontaneous at low temperatures but spontaneous at high temperatures, or not spontaneous at any temperature. Explain the reasons. (a) 2HgO(s) 2Hg(l) + O2(g) = 90.8 kJ → (b) 4Fe(s) + 302(g) → 2Fe2O3(s) AH = -1648.4 kJ (c) N2(g) + 3Cl2(g) → 2NC13(g) днө — 460 kJ 作答 (d) 2NH4NO3(s) → 2N2(g) + 4H2O(g) + O2(g) AH® = -225.5 kJ