For a spontaneous reaction ΔG must be negative. At threshold ΔG = 0
We know ΔG = ΔH - TΔS
For ΔG = 0
T = ΔH / ΔS
Given ΔH = 51 kJ mol-1 , ΔS = 118.74 J K-1 mol-1
Therefore T = 51 x 10 3 / 118.74 = 429.5 K
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9. A drug used to treat hypertension undergoes a decomposition reaction to give an insol- uble...
The
enthalpy of a certain reaction is +233 kj/mol and the entropy is
+110J/molk. Above what temperature will the reaction be
spontaneous.
The enthalpy of a certain reaction is +233 kJ/mol, and the entropy is +110 J/mol K. Above what temperature will the reaction be spontaneous? 8.
1.) Calculate ΔHºrxn ΔSsurr and ΔSºrxn to determine if the reaction is spontaneous at 298 K ΔHºf : PCl3(g) = -287 kj/mol ΔSºf : PCl3(g) = -3112 J/mol *K ΔSºf : P4(s) = 41.1 J/mol*K ΔSºf : Cl2(g)= 2230 J/mol *K P4(s) +6Cl2(g) ------> 4PCl3(g) 2.) Calculate ΔGºrxn from enthalpy and entropy values at 298 K 4NH3 (g) +5O2(g) -----> 4 NO(g) +6H2O(g) ΔHºf : NO(g) = 90.29 kj/mol ΔHºf: H2O(g) = -241.826 kJ/mol ΔHºf: NH3(g) = -45.9 kJ/mol ΔSºf : NO(g)...
Consider the reaction CO(g) + 3H2(9)—CH (9) +H20(9) for which AH° = -206.1 kJ and A Sº = -214.7 J/K at 298.15 K. (1) Calculate the entropy change of the UNIVERSE when 1.982 moles of CO(g) react under standard conditions at 298.15 K. A Suniverse JK (2) Is this reaction reactant or product favored under standard conditions? (3) If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction...
A critical reaction in the production of energy to do work or drive chemical reactions in biological systems is the hydrolysis of adenosine triphosphate, ATP, to adenosine diphosphate, ADP, as described by the reaction ATP(aq) + H,O(1) ADP(aq) + HPO- (aq) for which AG = -30.5 kJ/mol at 37.0 °C and pH 7.0. Calculate the value of AG xn in a biological cell in which [ATP] = 5.0 mm, (ADP) = 0.10 mM, and (HPO 1 - 5.0 mM. AG...
QUESTION 23 - For the reaction below at 298 K: 4NO (9) N20 (9) + N203 (9) AH = -192.7 kJ and AS = -308.2 J/K Which of the following statements is TRUE? AG >0 at 298K At higher temperatures, the reaction will be spontaneous At lower temperatures, the reaction will be spontAreous The reaction is spontaneous at all temperatures. None of the above are true. QUESTION 24 What is Asº at 298 K for the following reaction? 2 H2S(g)...
A reaction has an enthalpy change of - 71 kJ mol" and an entropy change of -58 JK-mol-. At what temperature does this exothermic reaction cease to be spontaneous? 422°C 673°c 826°C O 951°C What is the molar reaction enthalpy for the reaction below: N2H4(0) +CHNO(0) 4CHẠO(g) +Ng(g) + 3H (g) given the following thermodynamic data? 2NH3(9) ► N2H4(l) + H2(9) A,Hm = 22.5 kJ mol-1 2NH3(9) N2(g) + 3H2(9) A Hm = 57.5 kJ mol-1 CH,0(9) + H2(g) +...
9. The enthalpy of decomposition of gaseous water to oxygen and hydrogen at 298 K and 1 atm is 241.75 kJ/mol. Calculate its value at 348 K. The molar heat capacity values (in J/K.mol) are: Cm (H20) 33.56, C.m (O2) 29.12, Cm (H2) 28.82.
(1) The reaction the decomposition of ammonia is shown below. Calculate the total ∆H If bond energies in K/J: N≡N is 944, H-H is 436 and N-H is 388 Reactions: 2 NH3→N_2+3H_2 Explain reason for your answer (2) Which of the following statements is FALSE and why? A) Entropy is a state function. B) Endothermic processes decrease the entropy of surroundings, at constant T and P. C) Endothermic processes are never spontaneous. D) Entropy of the surroundings depends on the...
The vaporization of compound A is described by the following chemical equation. A(1) A(8) A rap(72.39 °C) = 38.21 kJ/mol Calculate the entropy of vaporization, Aswap, for A(l) at 25.0 °C given that the boiling point of A is 72.39 °C, and the molar heat capacity of A(l) is 119.09 J/mol K). Assume that the molar heat capacity of A(R) is 56.5% of that of A(1). ASP J. mol-K Calculate the standard enthalpy of vaporization. A Hap, for A(1) at...
Gaseous ozone undergoes decomposition according to the stochiometric equation: 203(g) →302 (g) Two alternative mechanisms have been proposed to account for this reaction. Mechanism 2 03 302 bimolecular, rate constant k Mechanism II 03 02 + fast equilibrium, equilibrium constant K1 0+ 03 — 202 slow, rate constant k2 A. Derive rate laws for the formation of O2 for each mechanism. B. Thermodynamic measurements give standard enthalpies of formation for each of the following species at 298 K: species AH°...