Using the equation $\Delta G^\circ = \Delta H^\circ - T\Delta S^\circ$: $$ \Delta G^\circ = 131.3\text kJ/mol - (298\text K)(0.1341\text kJ/mol\cdot\textK) $$ $$ \Delta G^\circ = 131.3 - 39.96 $$ $$ \Delta G^\circ = +91.3\text kJ/mol $$ (The positive $\Delta G^\circ$ indicates the reaction is non-spontaneous at standard conditions.)
The 1972 exam was notably lengthy, featuring compared to the 7 questions found on today’s exams. While the modern exam focuses heavily on particle-level representations and experimental design, the 1972 answers reveal a deep focus on stoichiometric precision and complex inorganic coordination . 1972 ap chemistry free response answers
The exam featured 18 free-response questions in total. Modular Scoring: Using the equation $\Delta G^\circ = \Delta H^\circ
Quantitative problems where students chose 4 out of 6 (35%). Notable Questions and Solutions 1. The Stoichiometry Puzzle (Acid-Base/Gases) Decant hot solution and cool → PbCl₂ recrystallizes
to the precipitate → PbCl₂ is slightly soluble in hot water; AgCl is not. Decant hot solution and cool → PbCl₂ recrystallizes (white needles). Confirm Pb²⁺ with 1M H2SO4 → white PbSO₄ precipitate.
[ E_cell = 1.10 - \frac0.05922 \log(100) ] [ \frac0.05922 = 0.0296 ] [ \log(100) = 2 ] [ E_cell = 1.10 - (0.0296 \times 2) = 1.10 - 0.0592 ] [ E_cell = 1.0408 , \textV ]
The exam also tested the types of isomerism possible when substituting one atom into ethane ( C2H6cap C sub 2 cap H sub 6 ) and ethene ( C2H4cap C sub 2 cap H sub 4