A sample consisting 3.0 moles of a perfect gas molecules initially at thermal equilibrium with the surroundings 273 K undergoes an irreversible isochoric change to a final temperture of 207 K. Calculate ∆Ssys, ∆Ssurr, and ∆Stotal for the process. Assume Cp,m is 7/2 R throughout the entire temperature range.

Consider the reaction 2NH3(g) + 3N₂O(g) → 4N₂ (9) + 3H₂O(g) for which AH° = − 879.5 kJ and AS° = 288.1 J/K at 298.15 K. 1. Calculate the entropy change of the UNIVERSE when 2.344 moles of NH3(g) react under standard conditions at 298.15 K. ASuniverse = J/K 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 is reactant favored, choose 'reactant favored'.

Thermodynamics Quantities for Selected Substances at 298.15 K (25⁰C) Substance ∆H⁰f (kJ/mol) ∆G⁰f (kJ/mol) S (J/K-mol) Carbon       C2H2(g) 226.7 209.2 200.8 C2H4(g) 52.30 68.11 219.4         Hydrogen       H2(g) 0 0 130.58         Oxygen       O2(g) 0 0 205.0 H2O(l) -285.83 -237.13 69.91 What is the ∆S⁰ for the catalytic hydrogenation of acetylene to ethene, C­2H­2(g) + H2(g) → C2H4(g) inJ/K?

The heat of fusion ΔHf of dichloromethane (CH2Cl2) is 6.2 kJ/mol. Calculate the change in entropy ΔS when 434.g of dichloromethane freezes at −95.1°C Be sure your answer contains a unit symbol and the correct number of significant digits.

For the reaction A (g) → 2 B (g), K = 14.7 at 298 K. What is the value of Q for this reaction at 298 K when ∆G = -4.5 kJ/mol?

Calculate the change in the molar entropy of solid sodium chloride at constant pressure (1.00 bar) during heating from 0°C to 400°C. The constant-pressure molar heat capacity of NaCl(s) – which is not constant - takes the following form. 45.94 J 16.32 x 10-3 J T. Cp,m3 K mol K2 mol