AP Chemistry — Practice

All practice problems and solutions for AP Chemistry, organized by unit. Worked examples stay on the unit pages.

Auto-collected from the practice sections of each unit’s notes (scripts/build_practice.py). Edit the source notes, not this page.

Unit 1: Atomic Structure and Properties

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Practice

MCQ

1. A neutral atom has the electron configuration $1s^2 2s^2 2p^6 3s^2 3p^4$. Which statement is correct?

   (A) The atom is in group 4 and forms $4+$ ions most often.
   (B) The atom is in group 16 and has six valence electrons.
   (C) The atom is a noble gas because the $3p$ subshell is occupied.
   (D) The atom has four valence electrons because the last exponent is $4$.

2. Which set of particles is arranged in order of increasing radius?

   (A) $\text{Cl}^- < \text{S}^{2-} < \text{K}^+$
   (B) $\text{K}^+ < \text{Cl}^- < \text{S}^{2-}$
   (C) $\text{S}^{2-} < \text{Cl}^- < \text{K}^+$
   (D) $\text{Cl}^- < \text{K}^+ < \text{S}^{2-}$

3. Which photon has the greatest energy?

   (A) A photon with wavelength $700\ \text{nm}$
   (B) A photon with wavelength $500\ \text{nm}$
   (C) A photon with wavelength $300\ \text{nm}$
   (D) A photon with wavelength $900\ \text{nm}$

4. Which statement best explains why first ionization energy generally increases from left to right across a period?

   (A) Atomic radius increases, so electrons are easier to remove.
   (B) Effective nuclear charge increases, so valence electrons are held more strongly.
   (C) Shielding increases sharply, so valence electrons are held more weakly.
   (D) The number of occupied principal energy levels increases.

5. Which element has the electron configuration $[\text{Ne}]3s^2 3p^1$?

   (A) Mg
   (B) Al
   (C) Si
   (D) P

6. Which set of quantum numbers is not allowed for an electron in an atom?

   (A) $n=2,\ l=1,\ m_l=0,\ m_s=+\frac12$
   (B) $n=3,\ l=2,\ m_l=-2,\ m_s=-\frac12$
   (C) $n=3,\ l=3,\ m_l=0,\ m_s=+\frac12$
   (D) $n=4,\ l=0,\ m_l=0,\ m_s=-\frac12$

FRQ

7. A sample of chlorine contains $75.78\%$ $^{35}\text{Cl}$ atoms and $24.22\%$ $^{37}\text{Cl}$ atoms.

   $(A)$ Calculate the average atomic mass of chlorine.

   $(B)$ Explain why the average atomic mass is closer to $35$ than to $37$.

   $(C)$ A PES spectrum for chlorine shows peaks from core electrons and valence electrons. Explain why core-electron peaks appear at higher binding energy than valence-electron peaks.

8. Sterling silver contains silver and copper. In a released AP Chemistry question, students compared atomic radii using Coulomb’s law. (Adapted from College Board, 2024 AP Chemistry FRQ 3.)

   $(A)$ Identify which atom has the larger atomic radius: $\text{Ag}$ or $\text{Cu}$.

   $(B)$ Use shell structure and Coulomb’s law to justify your answer.

   $(C)$ Explain why comparing only nuclear charge is not enough to predict the radius in this case.

Unit 2: Compound Structure and Properties

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Practice

MCQ

1. Which molecule is polar?

   (A) $\text{CO}_2$
   (B) $\text{BF}_3$
   (C) $\text{CH}_4$
   (D) $\text{NH}_3$

2. Which compound should have the greatest lattice energy magnitude?

   (A) $\text{NaF}$
   (B) $\text{NaCl}$
   (C) $\text{MgO}$
   (D) $\text{MgCl}_2$

3. Which species has a tetrahedral molecular geometry?

   (A) $\text{CO}_2$
   (B) $\text{NH}_3$
   (C) $\text{CH}_4$
   (D) $\text{BF}_3$

4. In a nitrate ion, $\text{NO}_3^-$, resonance means that

   (A) the atoms repeatedly switch positions.
   (B) one N-O bond is permanently double while the other two are permanently single.
   (C) the actual ion has three equivalent N-O bonds with bond order between single and double.
   (D) the ion violates conservation of charge.

5. Which molecule has a bent molecular geometry?

   (A) $\text{CO}_2$
   (B) $\text{H}_2\text{O}$
   (C) $\text{BF}_3$
   (D) $\text{CH}_4$

6. Which bond is most polar?

   (A) C-H
   (B) C-C
   (C) H-F
   (D) Cl-Cl

FRQ

7. Consider the molecules $\text{CH}_2\text{O}$ and $\text{CH}_3\text{OH}$.

   $(A)$ Draw a reasonable Lewis structure for each molecule.

   $(B)$ Identify the hybridization of the carbon atom in each molecule.

   $(C)$ Explain which molecule can form stronger intermolecular attractions with water.

8. The 2026 AP Chemistry exam asked students about chromate resonance and VSEPR geometry. (Adapted from College Board, 2026 AP Chemistry FRQ 2.)

   $(A)$ Predict the molecular geometry around chromium in $\text{CrO}_4^{2-}$.

   $(B)$ Explain why multiple resonance structures can be drawn for $\text{CrO}_4^{2-}$.

   $(C)$ Explain why the four Cr-O bonds are expected to be equivalent in the resonance hybrid.

Unit 3: Substances and Mixtures

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Practice

MCQ

1. Which substance is expected to have the highest boiling point?

   (A) $\text{CH}_4$
   (B) $\text{CH}_3\text{CH}_3$
   (C) $\text{CH}_3\text{OH}$
   (D) $\text{CH}_3\text{OCH}_3$

2. A solution is prepared by dissolving $0.250\ \text{mol}$ of $\text{NaCl}$ in enough water to make $0.500\ \text{L}$ of solution. Assuming complete dissociation, what is the approximate total particle concentration?

   (A) $0.250\ M$
   (B) $0.500\ M$
   (C) $1.00\ M$
   (D) $2.00\ M$

3. Which pair is most likely to be miscible?

   (A) Hexane and water
   (B) Ethanol and water
   (C) Sodium chloride and hexane
   (D) Oil and water

4. If the pressure of a gas above a liquid is increased at constant temperature, the solubility of the gas in the liquid generally

   (A) increases.
   (B) decreases.
   (C) remains exactly zero.
   (D) becomes independent of gas identity.

5. Which sample should behave most ideally as a gas?

   (A) $\text{NH}_3$ at high pressure and low temperature
   (B) $\text{CO}_2$ at high pressure and low temperature
   (C) He at low pressure and high temperature
   (D) $\text{H}_2\text{O}$ vapor near condensation

6. Which solution has the highest boiling point, assuming ideal behavior?

   (A) $0.10\ m$ glucose
   (B) $0.10\ m\ \text{NaCl}$
   (C) $0.10\ m\ \text{CaCl}_2$
   (D) pure water

FRQ

7. A student measures the absorbance of several solutions of $\text{Cu}^{2+}$ at the same wavelength and path length.

   $(A)$ Explain why absorbance can be used to determine concentration.

   $(B)$ A solution has absorbance $0.420$. A calibration line has equation $A=15.0c$, where $c$ is in $\text{mol/L}$. Calculate the concentration.

   $(C)$ Explain why the wavelength should be chosen near the color most strongly absorbed by the solution.

8. The 2026 AP Chemistry exam included a spectrophotometry particle-diagram question about absorbance and ion concentration. (Adapted from College Board, 2026 AP Chemistry FRQ 6.)

   $(A)$ Explain why a solution with greater concentration of colored ions has greater absorbance at a fixed wavelength.

   $(B)$ If a calibration curve has equation $A=4.00c$ and an unknown solution has $A=0.120$, calculate $c$.

   $(C)$ In a particle diagram of equal volume, how should the number of colored ions compare between a $0.020\ M$ solution and a $0.040\ M$ solution?

Unit 4: Chemical Reactions

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Practice

MCQ

1. What volume of $0.200\ M\ \text{NaOH}$ is required to neutralize $25.0\ \text{mL}$ of $0.100\ M\ \text{H}_2\text{SO}_4$?

   (A) $12.5\ \text{mL}$
   (B) $25.0\ \text{mL}$
   (C) $50.0\ \text{mL}$
   (D) $100.\ \text{mL}$

2. Which net ionic equation represents the precipitation reaction between aqueous $\text{AgNO}_3$ and aqueous $\text{NaCl}$?

   (A) $\text{Ag}^+(aq)+\text{Cl}^-(aq)\rightarrow\text{AgCl}(s)$
   (B) $\text{Na}^+(aq)+\text{NO}_3^-(aq)\rightarrow\text{NaNO}_3(s)$
   (C) $\text{Ag}^+(aq)+\text{NO}_3^-(aq)\rightarrow\text{AgNO}_3(s)$
   (D) $\text{Na}^+(aq)+\text{Cl}^-(aq)\rightarrow\text{NaCl}(s)$

3. In the reaction $\text{Zn}(s)+\text{Cu}^{2+}(aq)\rightarrow\text{Zn}^{2+}(aq)+\text{Cu}(s)$, which species is oxidized?

   (A) $\text{Zn}(s)$
   (B) $\text{Cu}^{2+}(aq)$
   (C) $\text{Zn}^{2+}(aq)$
   (D) $\text{Cu}(s)$

4. Which observation gives the strongest evidence that a precipitation reaction occurred?

   (A) The solution remains clear and colorless.
   (B) A solid appears after two aqueous solutions are mixed.
   (C) The total volume of solution increases.
   (D) The beaker is made of glass.

5. What is the oxidation number of sulfur in $\text{SO}_4^{2-}$?

   (A) $+2$
   (B) $+4$
   (C) $+6$
   (D) $-2$

6. Which pair of aqueous solutions will produce a precipitate when mixed?

   (A) $\text{NaNO}_3$ and $\text{KCl}$
   (B) $\text{BaCl}_2$ and $\text{Na}_2\text{SO}_4$
   (C) $\text{KNO}_3$ and $\text{NaC}_2\text{H}_3\text{O}_2$
   (D) $\text{NH}_4\text{Cl}$ and $\text{NaNO}_3$

FRQ

7. A $2.50\ \text{g}$ sample of impure $\text{CaCO}_3$ reacts with excess $\text{HCl}$ according to

$$\text{CaCO}_3(s)+2\text{HCl}(aq)\rightarrow \text{CaCl}_2(aq)+\text{CO}_2(g)+\text{H}_2\text{O}(l).$$

The reaction produces $0.0200\ \text{mol}$ of $\text{CO}_2$.

$(A)$ Calculate the moles of $\text{CaCO}_3$ that reacted.

$(B)$ Calculate the mass of $\text{CaCO}_3$ in the sample.

$(C)$ Calculate the percent by mass of $\text{CaCO}_3$ in the impure sample.

8. A released AP Chemistry question asked students to identify a limiting reactant from experimental data. (Adapted from College Board, 2024 AP Chemistry FRQ 2.)

   $(A)$ In a trial, $0.0300\ \text{mol}$ of $\text{Al}$ reacts with $0.0200\ \text{mol}$ of $\text{Cl}_2$ according to $2\text{Al}+3\text{Cl}_2\rightarrow2\text{AlCl}_3$. Identify the limiting reactant.

   $(B)$ Calculate the theoretical moles of $\text{AlCl}_3$ produced.

   $(C)$ Explain why the excess reactant remains after the limiting reactant is consumed.

Unit 5: Kinetics

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Practice

MCQ

1. For the reaction $A+B\rightarrow C$, the initial-rate data below are collected.

Trial	$[A]$	$[B]$	Initial rate
1	$0.10\ M$	$0.10\ M$	$2.0\times10^{-3}\ M/s$
2	$0.20\ M$	$0.10\ M$	$8.0\times10^{-3}\ M/s$
3	$0.20\ M$	$0.20\ M$	$8.0\times10^{-3}\ M/s$

What is the rate law?

(A) $\text{rate}=k[A][B]$
(B) $\text{rate}=k[A]^2$
(C) $\text{rate}=k[A]^2[B]$
(D) $\text{rate}=k[B]^2$

2. A catalyst increases the rate of a reaction by

   (A) increasing $\Delta G^\circ$
   (B) lowering the activation energy
   (C) increasing the equilibrium constant
   (D) increasing the enthalpy change of the reaction

3. For a first-order reaction, which plot should be linear?

   (A) $[A]$ versus time
   (B) $\ln[A]$ versus time
   (C) $1/[A]$ versus time
   (D) rate versus $1/T$

4. If the rate law is $\text{rate}=k[A]^2[B]$, what happens to the rate when $[A]$ is doubled and $[B]$ is held constant?

   (A) It doubles.
   (B) It triples.
   (C) It quadruples.
   (D) It stays the same.

5. A reaction has a rate law $\text{rate}=k[A]$. What are the units of $k$ if rate is measured in $M/s$?

   (A) $M^{-1}s^{-1}$
   (B) $s^{-1}$
   (C) $M/s$
   (D) $M^2/s$

6. Increasing temperature usually increases reaction rate because

   (A) the activation energy becomes zero.
   (B) more collisions have energy greater than or equal to $E_a$.
   (C) the equilibrium constant must become larger.
   (D) the reaction mechanism cannot change.

FRQ

7. A first-order decomposition has rate constant $k=0.0300\ \text{s}^{-1}$.

   $(A)$ Calculate the half-life.

   $(B)$ If the initial concentration is $0.800\ M$, calculate the concentration after $60.0\ \text{s}$.

   $(C)$ Explain how the slope of a graph of $\ln[A]$ versus time is related to $k$.

8. The 2026 AP Chemistry exam included a kinetics question using concentration-time data and a graph of natural log of concentration. (Adapted from College Board, 2026 AP Chemistry FRQ 2.)

   $(A)$ Explain how concentration-time data can support that a reaction is first order in a reactant.

   $(B)$ If a plot of $\ln[A]$ versus time has slope $-0.0150\ \text{s}^{-1}$, identify $k$.

   $(C)$ Calculate the half-life for the reaction.

Unit 6: Thermochemistry

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Practice

MCQ

1. A reaction has $\Delta H=-85\ \text{kJ/mol}$. Which statement is correct?

   (A) The reaction absorbs heat from the surroundings.
   (B) The products have greater enthalpy than the reactants.
   (C) The reaction is exothermic.
   (D) The reaction must be spontaneous at all temperatures.

2. A $50.0\ \text{g}$ sample of water is warmed from $22.0^\circ\text{C}$ to $28.0^\circ\text{C}$. Using $c=4.184\ \text{J/(g}\cdot^\circ\text{C)}$, how much heat is absorbed by the water?

   (A) $1.26\times10^2\ \text{J}$
   (B) $1.26\times10^3\ \text{J}$
   (C) $5.02\times10^3\ \text{J}$
   (D) $1.17\times10^4\ \text{J}$

3. Which process is endothermic?

   (A) Freezing water
   (B) Condensing steam
   (C) Burning methane
   (D) Vaporizing liquid water

4. In a coffee-cup calorimeter, the solution temperature increases. What is true about the reaction occurring in the solution?

   (A) The reaction releases heat to the solution.
   (B) The reaction absorbs heat from the solution.
   (C) The reaction has no enthalpy change.
   (D) The reaction must have $\Delta S<0$.

5. Which equation correctly represents Hess’s law?

   (A) $q=mc\Delta T$
   (B) $\Delta H_{\text{rxn}}=\sum \Delta H_{\text{steps}}$
   (C) $PV=nRT$
   (D) $K=\frac{[\text{products}]}{[\text{reactants}]}$

6. If bonds broken require $650\ \text{kJ}$ and bonds formed release $900\ \text{kJ}$, what is the approximate $\Delta H_{\text{rxn}}$?

   (A) $+250\ \text{kJ}$
   (B) $-250\ \text{kJ}$
   (C) $+1550\ \text{kJ}$
   (D) $-1550\ \text{kJ}$

FRQ

7. A reaction is represented by

$$2\text{H}_2(g)+\text{O}_2(g)\rightarrow2\text{H}_2\text{O}(l)$$

with $\Delta H^\circ_{\text{rxn}}=-572\ \text{kJ}$ for the reaction as written.

$(A)$ Calculate the enthalpy change for forming $1.00\ \text{mol}$ of $\text{H}_2\text{O}(l)$.

$(B)$ Calculate the enthalpy change when $4.00\ \text{mol}$ of $\text{H}_2(g)$ reacts completely.

$(C)$ Explain why breaking bonds is endothermic even when the overall reaction is exothermic.

8. The 2026 AP Chemistry exam included a sodium oxide thermochemistry problem using formation enthalpy and limiting reactants. (Adapted from College Board, 2026 AP Chemistry FRQ 7.)

   $(A)$ For $4\text{Na}(s)+\text{O}_2(g)\rightarrow2\text{Na}_2\text{O}(s)$ with $\Delta H^\circ_{\text{rxn}}=-828\ \text{kJ}$, calculate $\Delta H_f^\circ$ for $\text{Na}_2\text{O}(s)$.

   $(B)$ If $2.00\ \text{mol}$ Na reacts completely with excess oxygen, calculate the heat released.

   $(C)$ Explain why elements in their standard states have $\Delta H_f^\circ=0$.

Unit 7: Equilibrium

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Practice

MCQ

1. For the reaction $\text{N}_2(g)+3\text{H}_2(g)\rightleftharpoons2\text{NH}_3(g)$, which expression is $K_c$?

   (A) $\dfrac{[\text{NH}_3]}{[\text{N}_2][\text{H}_2]}$
   (B) $\dfrac{[\text{NH}_3]^2}{[\text{N}_2][\text{H}_2]^3}$
   (C) $\dfrac{[\text{N}_2][\text{H}_2]^3}{[\text{NH}_3]^2}$
   (D) $\dfrac{2[\text{NH}_3]}{[\text{N}_2]+3[\text{H}_2]}$

2. For a system at equilibrium, adding a catalyst will

   (A) increase $K$
   (B) decrease $K$
   (C) shift the equilibrium toward products
   (D) leave the equilibrium composition unchanged

3. If $Q>K$ for a reaction mixture, the reaction will proceed

   (A) toward products until equilibrium is reached.
   (B) toward reactants until equilibrium is reached.
   (C) in neither direction because it is already at equilibrium.
   (D) only if a catalyst is added.

4. Which species is omitted from the equilibrium expression for $\text{CaCO}_3(s)\rightleftharpoons\text{CaO}(s)+\text{CO}_2(g)$?

   (A) $\text{CO}_2(g)$ only
   (B) $\text{CaCO}_3(s)$ and $\text{CaO}(s)$
   (C) $\text{CaO}(s)$ and $\text{CO}_2(g)$
   (D) all species

5. For $\text{AgCl}(s)\rightleftharpoons\text{Ag}^+(aq)+\text{Cl}^-(aq)$, what is the expression for $K_{sp}$?

   (A) $[\text{Ag}^+][\text{Cl}^-]$
   (B) $\dfrac{[\text{Ag}^+][\text{Cl}^-]}{[\text{AgCl}]}$
   (C) $[\text{AgCl}]$
   (D) $\dfrac{1}{[\text{Ag}^+][\text{Cl}^-]}$

6. If an exothermic equilibrium reaction is heated, the equilibrium shifts

   (A) toward products.
   (B) toward reactants.
   (C) nowhere, because temperature does not affect equilibrium.
   (D) only if a catalyst is present.

FRQ

7. At a certain temperature, $K_c=4.00$ for

$$\text{A}(g)\rightleftharpoons2\text{B}(g).$$

A sealed container initially has $0.600\ M$ $\text{A}$ and no $\text{B}$.

$(A)$ Write the equilibrium-constant expression.

$(B)$ Set up an ICE table using $x$ for the amount of $\text{A}$ consumed.

$(C)$ Calculate the equilibrium concentrations of $\text{A}$ and $\text{B}$.

8. The 2024 AP Chemistry exam included an equilibrium particle-diagram question for $\text{H}_2(g)+\text{I}_2(g)\rightleftharpoons2\text{HI}(g)$. (Adapted from College Board, 2024 AP Chemistry FRQ 5.)

   $(A)$ Write the expression for $Q$.

   $(B)$ If $[\text{H}_2]=0.20\ M$, $[\text{I}_2]=0.10\ M$, and $[\text{HI}]=0.30\ M$, calculate $Q$.

   $(C)$ If $K=50$, predict the direction the system shifts.

Unit 8: Acid-Base Equilibrium

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Practice

MCQ

1. What is the $\text{pH}$ of a $1.0\times10^{-3}\ M$ solution of $\text{HCl}$ at $25^\circ\text{C}$?

   (A) $1.00$
   (B) $3.00$
   (C) $7.00$
   (D) $11.00$

2. A buffer contains equal concentrations of $\text{HF}$ and $\text{F}^-$. If $K_a$ for $\text{HF}$ is $6.8\times10^{-4}$, what is the $\text{pH}$ of the buffer?

   (A) $1.68$
   (B) $3.17$
   (C) $7.00$
   (D) $10.83$

3. Which solution has the greatest $\text{pH}$?

   (A) $0.10\ M\ \text{HCl}$
   (B) $0.10\ M\ \text{HC}_2\text{H}_3\text{O}_2$
   (C) $0.10\ M\ \text{NaCl}$
   (D) $0.10\ M\ \text{NaOH}$

4. At the half-equivalence point in a weak acid-strong base titration,

   (A) $\text{pH}=\text{p}K_a$.
   (B) $\text{pH}=7.00$ for every weak acid.
   (C) all weak acid has been converted to conjugate base.
   (D) $[\text{H}_3\text{O}^+]=[\text{OH}^-]$.

5. Which species is the conjugate base of $\text{H}_2\text{PO}_4^-$?

   (A) $\text{H}_3\text{PO}_4$
   (B) $\text{HPO}_4^{2-}$
   (C) $\text{PO}_4^{3-}$
   (D) $\text{OH}^-$

6. Which mixture is a buffer?

   (A) $\text{HCl}$ and $\text{NaCl}$
   (B) $\text{NaOH}$ and $\text{NaCl}$
   (C) $\text{HF}$ and $\text{NaF}$
   (D) $\text{HNO}_3$ and $\text{NaNO}_3$

FRQ

7. A $0.100\ M$ solution of acetic acid, $\text{HC}_2\text{H}_3\text{O}_2$, has $K_a=1.8\times10^{-5}$.

   $(A)$ Write the acid-ionization equation.

   $(B)$ Calculate $[\text{H}_3\text{O}^+]$ using the small-$x$ approximation.

   $(C)$ Calculate the $\text{pH}$.

   $(D)$ Explain what happens to the percent ionization if sodium acetate is added.

8. The 2026 AP Chemistry exam included a nitrous acid titration and indicator question. (Adapted from College Board, 2026 AP Chemistry FRQ 3.)

   $(A)$ Explain why the equivalence point of a weak acid-strong base titration has $\text{pH}>7$.

   $(B)$ A $35.0\ \text{mL}$ sample of $\text{HNO}_2$ is titrated to equivalence with $21.0\ \text{mL}$ of $0.160\ M\ \text{NaOH}$. Calculate the molarity of $\text{HNO}_2$.

   $(C)$ Explain why an indicator should change color near the steep part of the titration curve.

Unit 9: Thermodynamics and Electrochemistry

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Practice

MCQ

1. For a spontaneous galvanic cell under standard conditions, which statement is correct?

   (A) $E^\circ_{\text{cell}}<0$ and $\Delta G^\circ<0$
   (B) $E^\circ_{\text{cell}}>0$ and $\Delta G^\circ<0$
   (C) $E^\circ_{\text{cell}}>0$ and $\Delta G^\circ>0$
   (D) $E^\circ_{\text{cell}}=0$ and $\Delta G^\circ=0$

2. Which change always increases the entropy of the system?

   (A) $\text{H}_2\text{O}(g)\rightarrow\text{H}_2\text{O}(l)$
   (B) $\text{NaCl}(aq)\rightarrow\text{NaCl}(s)$
   (C) $\text{CO}_2(s)\rightarrow\text{CO}_2(g)$
   (D) $2\text{NO}_2(g)\rightarrow\text{N}_2\text{O}_4(g)$

3. A reaction has $\Delta H^\circ>0$ and $\Delta S^\circ>0$. The reaction is most likely thermodynamically favorable at

   (A) low temperatures only.
   (B) high temperatures only.
   (C) all temperatures.
   (D) no temperatures.

4. In an electrolytic cell, oxidation occurs at the

   (A) anode.
   (B) cathode.
   (C) salt bridge.
   (D) voltmeter.

5. If $\Delta G^\circ<0$ for a reaction under standard conditions, which statement is true?

   (A) $K<1$
   (B) $K=1$
   (C) $K>1$
   (D) $E^\circ_{\text{cell}}<0$ for the corresponding galvanic cell

6. What mass of Ag is plated by $1.00\ \text{mol}$ of electrons from $\text{Ag}^+$?

   (A) $53.9\ \text{g}$
   (B) $107.9\ \text{g}$
   (C) $215.8\ \text{g}$
   (D) $96500\ \text{g}$

FRQ

7. A galvanic cell is based on the reaction

$$\text{Zn}(s)+\text{Cu}^{2+}(aq)\rightarrow\text{Zn}^{2+}(aq)+\text{Cu}(s).$$

Use $E^\circ_{\text{red}}(\text{Cu}^{2+}/\text{Cu})=+0.34\ \text{V}$ and $E^\circ_{\text{red}}(\text{Zn}^{2+}/\text{Zn})=-0.76\ \text{V}$.

$(A)$ Identify the anode and cathode.

$(B)$ Calculate $E^\circ_{\text{cell}}$.

$(C)$ Calculate $\Delta G^\circ$ for the reaction.

$(D)$ Explain the direction of electron flow in the external circuit.

8. The 2024 AP Chemistry exam included electroplating and nonspontaneous electrochemistry in a sterling silver context. (Adapted from College Board, 2024 AP Chemistry FRQ 3.)

   $(A)$ Explain why an electrolytic plating process requires an external power source.

   $(B)$ Calculate the time required to plate $1.00\ \text{g}$ of $\text{Cu}(s)$ from $\text{Cu}^{2+}$ using a current of $2.00\ \text{A}$.

   $(C)$ Identify whether reduction or oxidation occurs at the object being plated.