1972 Ap Chemistry Free Response Answers Fixed Today

A 0.500 g sample of an unknown monoprotic weak acid (HA) is dissolved in water and titrated with 0.100 M NaOH. It requires 40.0 mL of NaOH to reach the phenolphthalein endpoint. Calculate the molar mass of HA.

An electrolytic cell uses an external electric current to drive a non-spontaneous redox reaction, while a galvanic cell generates an electric current from a spontaneous redox reaction.

(a) A 249 milliliter sample of dry CO₂ gas, measured at 22°C and 740 torr, is obtained from this reaction. What is the percentage of potassium carbonate in the mixture? 1972 ap chemistry free response answers

Approximately 27.9% of the mixture is potassium carbonate. This is calculated by first determining the number of moles of CO₂ produced, which is equal to the moles of K₂CO₃ in the mixture, using the ideal gas law. The calculation uses the given values: volume (0.249 L), temperature (295.15 K), and pressure (740 torr) to find the moles of CO₂. Then, the mass of K₂CO₃ is calculated and divided by the total sample mass (5.00 g) to obtain the percentage.

. Multiplying by the molar mass (138.2 g/mol) gives 1.38 g, which is of the 5.00 g mixture. Mass of KOHcap K cap O cap H : To find the KOHcap K cap O cap H mass, calculate total HClcap H cap C l ). Subtract the HClcap H cap C l that reacted with K2CO3cap K sub 2 cap C cap O sub 3 (0.0200 mol) and the excess HClcap H cap C l An electrolytic cell uses an external electric current

In 1972, the AP Chemistry exam required students to demonstrate deep, theoretical knowledge alongside rigorous mathematical application. The FRQ section focused heavily on:

The 1972 focus on transition metal isomerism is highly relevant to today's AP curriculum. Where to Find Full 1972 FRQ Solutions Approximately 27

Therefore:

CO₂ is the gas that dissolves in water to form a weakly acidic solution. The chemical equation is: CO₂(g) + H₂O(l) ⇌ H₂CO₃(aq) ⇌ H⁺(aq) + HCO₃⁻(aq)

$$ \textMass of Oxygen = \textMass of Oxide - \textMass of Metal $$ $$ \textMass O = 0.711\text g - 0.500\text g = 0.211\text g $$