9.1 & 9.2 Entropy

Multiple Choice

Positive $$\Delta H$$ means the reaction is...

• Exothermic

• Endothermic

Multiple Choice

a mixture of gases is separated into 2 different containers

• + $$\Delta S$$

• - $$\Delta S$$

Multiple Choice

C₂H₆ (g) --> C₂H₄ (g) + H₂ (g)

• + $$\Delta S$$

• - $$\Delta S$$

Multiple Choice

Which has a positive sign for S?

• 2Na (s) + Cl₂ (g) --> 2NaCl (s)

• H₂O (g) --> H₂O (l)

• H⁺ (aq) + NO₃^- (aq) --> HNO₃ (l)

• CaCl₂ (s) --> Ca²⁺ (aq) + 2Cl^- (aq)

Multiple Choice

The oxidation of PCl₃(g) is represented by the equation above, and the table provides the approximate values of the absolute molar entropies, S°, for these substances. Based on the information given, what is the approximate ΔS° for the reaction?

• +170J/(mol_rxn⋅K)

• −170J/(mol_rxn⋅K)

• +190J/(mol_rxn⋅K)

• −190J/(mol_rxn⋅K)