# Problem: Without doing any calculations, determine the sign of ΔSsys for each of the following chemical reactions.a. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), ΔH˚rxn = –2044 kJb. N2(g) + O2(g) → 2 NO(g), ΔH˚rxn = +182.6 kJc. 2 N2(g) + O2(g) → 2 N2O(g), ΔH˚rxn  = +163.2 kJd. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g), ΔH˚rxn = –906 kJ

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a. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), ΔH˚rxn = –2044 kJ

• all compounds are gases
• reactants: 6 moles
• products: 7 moles
• increase in moles of gas → positive entropy → + ΔS°sys ###### Problem Details

Without doing any calculations, determine the sign of ΔSsys for each of the following chemical reactions.
a. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), ΔH˚rxn = –2044 kJ
b. N2(g) + O2(g) → 2 NO(g), ΔH˚rxn = +182.6 kJ
c. 2 N2(g) + O2(g) → 2 N2O(g), ΔH˚rxn  = +163.2 kJ
d. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g), ΔH˚rxn = –906 kJ