Consider the reaction: 4HCl(g) + O₂(g) → 2H₂O(g) + 2Cl₂ (g) Using standard absolute entropies at 298 K, calculate the entropy change for the system when 1.90 moles of HCl(g) react at standard conditions. AS⁰ Substance So (J/K mol) HCl(g) 186.9 O₂(g) 205.1 H₂O(g) 188.8 Cl₂ (g) 223.1 system J/K

Using the data in the table, calculate the standard entropy changes for the following reactions at 25°C. S(s) + O2(g) → S02(g) Species [J/(mol K)] S(s) 167.83 J/(mol K) O2(g) 205.15 MGCO3(s) → MgO(s) + CO2(g) SO,(g) 248.22 MGCO3(s) 65.7 J/(mol K) MgO(s) 27.0 CO28) 213.78 2 C,H,(g) + 7 O2g)→ 4 CO2(g) + 6 H2O(1) C;Hg) 229.16 J/(mol K) H,0() 69.95

Acetone, CH; COCH3 , boils at 56°C. The heat of vaporization of acetone at this temperature is 29.1 kJ/mol. What is the entropy change when 9 mol of liquid acetone vaporizes at 56°C?

Standard Entropy of Reaction Molecular systems tend to move spontaneously to a state of maximum randomness or disorder. Molecular randomness, or disorder, is called entropy and is denoted by the symbol S. As a state function, entropy change, A.S. depends only on initial and final states. AS has a positive value when disorder increases and a negative value when disorder decreases. The following conditions usually result in an increase in entropy: • a change of phase: solid-liquid-gas, an increase in the number of gas molecules, or • a solid dissolving to form a solution. Although the sign of the entropy change can be predicted as described above, the actual value of AS° must be calculated from the absolute entropy values. Sº, of the reactants and products: ASS° (products) - S° (reactants) ▼ Part A Predict the sign of the entropy change. AS°, for each of the reaction displayed. Drag the appropriate items to their respective bins. ▸ View Available Hint(s) Positive Submit H₂O(1) H₂O(g)…