ACS General Chemistry 2 Practice Exam

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• If the equilibrium constant K is much larger than 1, what can be said about ΔG° at that temperature?
• What is the difference between the reaction quotient Q and the equilibrium constant K?
• What is the value of ΔG° when K = 1?
• How many grams of copper are deposited in 60.0 minutes at 1.26 A?
• Gas solubility generally increases when temperature decreases. Which option correctly identifies this statement?
• In a concentration cell, what is the emf when both solutions have identical concentrations?
• What is the effect of adding a common ion on the solubility of a sparingly soluble salt?
• For an endothermic dissolution process, what is the typical effect of increasing temperature on the solubility and Ksp?
• State Raoult's law for an ideal solution.
• State Henderson-Hasselbalch equation and its common-use scenario.
• In hard water containing Ca^2+ at 2.0 × 10^−2 M, what is the maximum fluoride concentration allowed before CaF2(s) begins to precipitate, given Ksp = 4.0 × 10^−11?
• What is the relationship between the equilibrium constant K and the reaction quotient Q?
• Do catalysts change the position of chemical equilibrium?
• If a reaction has ΔH < 0 and ΔS > 0, the process is spontaneous:
• If ΔG = ΔH − TΔS, which statement is true when ΔG < 0 at a given temperature?
• Which constant equals approximately 96485 C/mol and relates electric charge to moles of electrons?
• If the standard cell potential E° is positive, what is the sign of ΔG°?
• What is the pH of a 0.10 M strong acid solution like HCl?
• When comparing Q and Ksp for an unsaturated solution, which statement is correct?
• Which term describes the cell potential measured when no current flows (open-circuit condition)?
• How does a catalyst affect a reaction's activation energy and rate?
• What is Kw and its value at 25°C?
• If the standard cell potential for a reaction is positive, the reaction is:
• What is the van't Hoff equation for osmotic pressure in dilute solutions?
• In a buffer solution near its pKa, the pH changes slowly with added acid or base, and pH is approximately equal to pKa when:
• A solution contains 0.002 M Pb^2+ and 0.002 M Ag^+. When NaCl(s) is added to raise Cl− to 0.01 M, which substance precipitates first or at all?
• For the reaction: NO2 (g) + F2 (g) ⇌ 2 NO2F (g), a proposed mechanism has the slow step NO2 + F2 ⇌ NO2F + F and a fast step NO2 + F ⇌ NO2F. What is the rate law for this mechanism?
• An oxidation-reduction reaction in which 3 electrons are transferred has a Delta G° = 18.55 kJ/mol at 25 degrees C. What is the value of E°?
• What is the coefficient for the nitrate ion (NO2−) when the redox reaction is balanced in basic solution? MnO4− (aq) + NO2− (aq) → MnO2 (s) + NO3− (aq)
• In a phase diagram, what does the line between two phases represent?
• What is the value of the equilibrium constant K for the overall reaction Cr(OH)3(s) + OH−(aq) ⇌ [Cr(OH)4]−(aq) given Ksp = 1.6 × 10^−30 and Kf = 8.0 × 10^29?
• Which entropy value is incorrectly reported at 298 K among the following species: Ca (s) S' = 202; Br2 (l) S' = 152; CO2 (g) S' = 214; AlCl3 (s) S' = 109?
• Which expression represents the first law of thermodynamics in terms of ΔU, q, and w?
• In beta decay, what happens to the mass number A?
• The half-life for the first-order conversion of cyclobutene to ethylene is 22.7 s at a given temperature. How many seconds are needed for the partial pressure of cyclobutene to decrease from 100 mmHg to 10 mmHg?
• An acetate buffer contains equal volumes of 0.35 M HC2H3O2 (pKa = 4.74) and 0.55 M NaC2H3O2. What is the pH of the buffer?
• What is the Clapeyron equation and what does it relate?
• If reaction quotient Q equals 1, what is ΔG relative to ΔG°?
• What is the physical meaning of the Arrhenius pre-exponential factor A in k = A e^(−Ea/RT)?
• What effect does a catalyst have on the activation energy and reaction rate?
• Which statement best describes colligative properties?
• For an ideal gas expanding reversibly from volume V1 to V2 at constant temperature, which expression correctly gives ΔS?
• Define buffer capacity and buffer range.
• In Henry's law S = k_H p, with S in mol/L and p in atm, what are the units of k_H?
• What defines a concentration cell and its emf?
• If a saturated solution of MgCO3 is placed in contact with a large supply of Mg2+ ions, what happens to its solubility?
• What is Henry's law and when is it applicable?
• How does increasing total pressure affect the solubility of gases in liquids?
• For the concentration cell Fe(s) | Fe3+ (0.100 M) || Fe3+ (1.00 M) | Fe(s) at 25 C, what is Ecell in millivolts?
• At equilibrium, what is true about the rates of the forward and reverse reactions?
• In the proposed mechanism for NO2 + F2 reaction, which step is rate-determining?
• For a second-order reaction with a single reactant, the integrated rate law is which form?
• Consider the reaction Cu2+ (aq) + Fe (s) → Cu (s) + Fe2+ (aq) E° = 0.78 V. What is the value of E when [Cu2+] = 0.040 M and [Fe2+] = 0.40 M?
• Using Henderson-Hasselbalch for a weak acid: pH = pKa + log([A−]/[HA]). If a strong base is added to a weak acid buffer, what happens to the ratio and pH?
• Which of the following are colligative properties?
• During electrolysis of molten sodium iodide, what is the half-reaction occurring at the anode?
• Given the standard reduction potentials at 25 degrees C, what is the standard cell potential of a Ni (s) | Ni2+ (aq) || Ag+ (aq) | Ag (s) galvanic cell?
• Write the Ksp expression for Ca(OH)2(s) ⇌ Ca2+(aq) + 2 OH−(aq).
• If a gas-phase equilibrium A ⇌ B has Δn_gas = 0, what is the relationship between Kp and Kc?
• Which expression correctly relates Gibbs free energy change to enthalpy and entropy at constant pressure and temperature?
• How do you compute ΔHrxn° from standard enthalpies of formation?
• Which statement best describes how to determine entropy-driven versus enthalpy-driven using ΔG = ΔH − TΔS?
• At a constant current of 1.26 A, how many grams of copper are deposited in 50.0 minutes?
• Which rate law is correct for the reaction 2H2 (g) + 2NO (g) → N2 (g) + 2H2O (g)?
• In the electrolysis of molten sodium iodide, which species is oxidized at the anode?
• What happens at the critical point on a phase diagram?
• Which expression correctly approximates the pH of a dilute solution of a monoprotic weak acid with concentration C and Ka?
• In the gas-phase equilibrium 2BrCl(g) ⇌ Br2(g) + Cl2(g), what happens if the container volume is decreased (pressure increased) at constant temperature?
• The mass of copper deposited by electrolysis is proportional to which of the following?
• How is the standard cell potential E°cell determined from half-cell potentials?
• For the reaction CH3COCH3(g) + 4 O2(g) → 3 CO2(g) + 3 H2O(l) at 25 °C with ΔH' = −184 kJ/mol and ΔS' = −236 J/mol·K, what is ΔG'?
• What is the Arrhenius equation and how does temperature affect k?
• Which action increases the concentration of gas dissolved in a liquid?
• If a sparingly soluble salt is added to solution with a common ion, what happens to its solubility?
• What is the equilibrium expression for Ni(CO)4 (g) ⇌ Ni (s) + 4 CO (g)?
• In a binary alloy AB at a certain temperature, two solid phases α and β have compositions Xα = 0.25 and Xβ = 0.75 (mole fraction of B). If the overall alloy composition is X0 = 0.50, what is the fraction of α phase present according to the lever rule?
• For the reaction A + B → C + D, rate law is first order in [A] and second order in [B]. If [A] is halved and [B] is doubled, the rate of the reaction will
• In a concentration cell, increasing the concentration difference between the two half-cells has what effect on the cell emf?
• Using pKa ≈ 4.76 for acetic acid, estimate the pH of a 0.10 M acetate buffer with equal 0.10 M acetic acid and acetate.
• What is the pH at the equivalence point for a strong acid-strong base titration?
• What is the value of ΔG for a system at equilibrium?
• In acidic solution, the half-reactions during electrolysis of water are:
• Describe the common method to balance redox reactions in acidic solution.
• Which half-life expression is correct for a zero-order reaction?
• Write the solubility product expression for PbSO4(s) ⇌ Pb2+(aq) + SO4^2−(aq) and interpret Ksp.
• For the equilibrium A ⇌ B with K = [B]/[A], what happens to [A] and [B] if more A is added?
• How does formation of a complex ion affect the solubility of a sparingly soluble salt?
• State the Nernst equation for a half-cell reaction at 25°C.
• What thermodynamic criterion determines spontaneity of a process at constant temperature and pressure?
• In a concentration cell with identical electrodes, what is the emf when the ion concentrations are equal on both sides?
• Buffer capacity is influenced by concentration and pH relative to pKa. Which statement is true?
• Which information is used to determine the order of a reaction with respect to a given species from rate data?
• If a binary alloy (C = 2) exists with two phases at fixed T and P, how many degrees of freedom F are allowed?
• One Faraday equals how many coulombs?
• For a reaction A ⇌ B, if the reaction quotient Q is less than the equilibrium constant K, in which direction will the reaction proceed?
• What is the standard Gibbs free energy change for the formation of one mole of ammonia from its elements under standard conditions?
• According to the Arrhenius equation, what is the effect of increasing temperature on the rate constant k when Ea > 0?
• For a reaction where K > 1 at all temperatures, which statement(s) must be true?
• What are ΔHfus and ΔHvap?
• Standard reduction potentials can be used to judge spontaneity of a redox reaction by:
• What is the Ksp expression for MgCO3 in water?
• Why doesn't a catalyst alter the final equilibrium composition?
• What is the overall order of the reaction for rate = k [H2] [NO]^2?
• Why does Fe(OH)3 solubility increase under acidic conditions?
• Phosgene decomposes into carbon monoxide and elemental chlorine. If the initial concentration of COCl2 (g) is 0.50 M, what is the equilibrium concentration of CO (g)? Ke = 6.6 x 10^-8
• Which factors determine boiling point elevation and freezing point depression for a given solute?
• In the dissolution of Ca(OH)2, the hydroxide ion appears to the power of what in the Ksp expression?
• A freezing point depression problem: A solute lowers the freezing point by 6.36 °C in 1.00 kg of water. Using Kf for water = 1.86 °C/m and assuming the solute dissociates into two particles, which compound is the unknown solute? (CsCl, KCl, LiF, NaCl)
• For rate = k [H2] [NO]^2, if [H2] is doubled, the rate increases by what factor?
• At the equivalence point of a weak acid-strong base titration, the pH is:
• In a reaction mechanism, what is the steady-state approximation?
• Le Chatelier's principle: how does increasing temperature affect an exothermic reaction's equilibrium?
• In a sealed container at 25°C, the gas-phase equilibrium 2BrCl(g) ⇌ Br2(g) + Cl2(g) has Kp = 0.130. If initially BrCl(g) = 0.400 atm, Br2(g) = 0.800 atm, and Cl2(g) = 0.800 atm, what is the BrCl(g) partial pressure at equilibrium?
• Which statement about spontaneity and ΔG = ΔH − TΔS is true?
• Which statement is true about the relationship between Q and K at equilibrium?
• For a first-order reaction, the half-life t1/2 is related to k by which expression?
• Which statement is correct for the reaction below under standard conditions? 2Cl2 (g) + 2NO (g) → N2 (g) + 2Cl2O (g); ΔH° = -22.0 kJ/mol
• In Ni(CO)4 (g) ⇌ Ni(s) + 4 CO (g), why is the activity of Ni(s) not included in the equilibrium expression?
• State Raoult's law for vapor pressures in a mixture of two volatile solvents.
• Which factor generally increases the solubility of sparingly soluble salts?
• Which statement correctly describes Raoult's law and Henry's law?
• Which relation connects Gibbs free energy change and cell potential for a galvanic cell?
• Distinguish between solubility and dissolution rate; how does temperature typically affect each for a salt?
• In the equation m = (I t)/(n F) × M, what does F represent?
• For a reaction with Q > K, which direction will the reaction proceed?
• What is the overall balanced equation for the electrolysis of water in acidic solution?
• Which describes the conjugate acid of NH3?
• Le Châtelier's principle predicts that increasing pressure will shift equilibria toward the side with fewer moles of gas. This statement applies to...
• In constant-pressure calorimetry, what is the sign convention for qrxn and qcal?
• At 1.26 A, how long (in minutes) would it take to deposit 1.00 g of copper?
• What is the mass of ethanol in the 200 g sample described above (89% by mass ethanol)?
• The activation energy for a particular reaction is 83.1 kJ/mol. By what factor will the rate constant increase when the temperature is increased from 550.0 degrees C to 60.0 degrees C?
• In a weak acid–strong base titration, the pH at the equivalence point is
• If Q is the reaction quotient and K is the equilibrium constant, which statement is true when Q < K?
• Henry's law connects partial pressure of a gas with what property of the dissolved gas in the liquid?
• Explain the common-ion effect and its impact on solubility.
• What are the units of molality?
• Lowering the pH (making the solution more acidic) has what effect on the solubility of metal hydroxides such as Fe(OH)3?
• Which statement about hydrolysis of salts is correct?
• An acetate buffer is prepared with 0.100 M HOAc and 0.100 M NaOAc. If pKa(HOAc) = 4.74, what is the pH?
• Which change is most likely to be accompanied by an increase in entropy?
• The standard Gibbs free energy change ΔG° is related to standard cell potential E° by which equation?
• If a solute does not dissociate in solution, its van't Hoff factor i is approximately
• What is the correct statement about the autoionization of water at 25°C?
• A nonvolatile solute is added to a volatile solvent. According to Raoult's law, the solvent's vapor pressure:
• A solution consists of 20.5 g of NaCl dissolved in 100 g of solution. What is the molality of NaCl in this solution?
• Which anion is the most basic?
• Which statement best describes osmotic pressure?
• How does complex formation with ligands affect solubility of a sparingly soluble salt?
• For a spontaneous galvanic cell, what is the sign of ΔG?
• Which expression represents the Nernst equation at 25°C for a cell reaction that transfers n electrons?
• Which statement about solubility in a solution with a common ion is true?
• What does the van't Hoff factor i account for in colligative properties?
• Calculate the standard Gibbs free energy change at 298 K for the reaction FeO4 (s) + 4 CO (g) ⇌ 3 Fe (s) + 4 CO2 (g).
• Describe the general steps of an ICE table for the reaction aA + bB ⇌ cC + dD to find equilibrium concentrations.
• Which statement about the cathode in a galvanic cell is true?
• What is the expression for osmotic pressure in dilute solutions?
• Beta decay of an atom with atomic number 53 and mass number 131 yields a residual atom with which Z and A?
• At constant pressure, heat flow equals which thermodynamic quantity?
• In rate law rate = k[A]^m[B]^n, the exponents m and n represent what?
• During the reduction of copper(II) oxide by carbon monoxide, CuO(s) + CO(g) ⇌ Cu(s) + CO2(g), which change will drive the equilibrium toward more Cu(s) production?
• Which law relates vapor pressure of a liquid mixture to the mole fraction of solvent in an ideal solution?
• For a zero-order reaction, the integrated rate law is which expression?
• In beta decay, what happens to the atomic number Z?
• What volume (in mL) of 0.150 M NaOH (aq) is required to neutralize 25.0 mL of 0.100 M H2SO4 (aq)?
• In a buffer where [A−] equals [HA], what is pH relative to pKa?
• What is a concentration cell?
• In a ternary eutectic system, what occurs at the eutectic point?
• At constant volume, the change in internal energy is equal to which of the following?
• What is the integrated rate law for a first-order reaction?
• What is the atomic number of iodine?
• If the initial-rate data show that doubling [A] while keeping [B] constant doubles the rate, what is the order with respect to A?
• What is the basic operating principle of a galvanic (electrochemical) cell?
• Which equation correctly relates standard Gibbs free energy change to the equilibrium constant at a given temperature?
• For the dissolution of BaSO4(s) ⇌ Ba^2+(aq) + SO4^2−(aq), if the solubility is s, which expression gives Ksp?
• What is the pH of a 0.820 M aqueous ammonia solution? Ka? Kb (NH3) = 1.8 × 10^-5
• Colligative properties depend on which characteristic of solute particles?
• Which statement best describes how the observed rate law is determined in a mechanism?
• In a pressure–volume system, which type of work is zero when the volume is held constant?
• For dissolution endothermic with positive ΔS, how does ΔG° change with increasing temperature?
• Which compound has the highest molar solubility in water given the following Ksp values: AgI 8.52 × 10^−17; BaCO3 2.58 × 10^−9; Fe(OH)3 2.79 × 10^−39; ZnS 3.00 × 10^−23?
• In copper plating from a Cu2+-containing solution, which half-reaction occurs at the cathode?
• Which statement correctly differentiates solubility from dissolution rate?
• Which 0.1 molal aqueous solution will have the lowest freezing point?
• How do you compute the standard cell potential E°cell from two half-reactions?
• Consider the equilibrium 2SO2 (g) + O2 (g) ⇌ 2SO3 (g). The forward reaction rate is observed to increase when the pressure is raised. What is the expected effect on the forward rate and the equilibrium yield of SO3?
• Which statement about the Arrhenius temperature dependence of the rate constant k is correct?
• Write the Ksp expression for AB(s) ⇌ A+(aq) + B−(aq).
• Henry's law states that the concentration of a dissolved gas is proportional to its partial pressure, described by C = kH P. Under constant temperature, doubling P will:
• Which substance dissolves in water to produce an acidic solution?
• For the equilibrium COCl2 (g) ⇌ CO (g) + Cl2 (g), what is the expression for Ke in terms of concentrations?
• Solubility product constant Ksp for Mg(OH)2 is sought when its molar solubility in water is 1.6 × 10^−4 M. Which value is correct for Ksp?
• An equilibrium mixture of I2 (g), Cl2 (g), and ICl (g) at 298 K has partial pressures of 0.0100 atm, 0.0100 atm, and 0.0900 atm, respectively. What is ΔG° at 298 K for the reaction I2 (g) + Cl2 (g) ⇌ 2 ICl (g)?
• If a nonvolatile solute is added to a solvent, what happens to the freezing point?
• In constant-pressure calorimetry, for an endothermic reaction, which statement about qrxn and qcal is true?
• In a multi-step reaction, what is the rate-determining step?
• Which statement correctly describes a galvanic cell with a positive standard cell potential E°cell?
• Which statement correctly describes buffer capacity?
• When NH4NO3 dissolves in water, the temperature of the solution decreases. What describes the enthalpy change, entropy change, and which change drives the process?
• What is the mole fraction of water in 200 g of a solution that is 89% by mass ethanol (C2H5OH)?
• What is the Gibbs phase rule for a system with C components and P phases at fixed temperature and pressure? F = ?
• Which change will alter the value of Ksp for the salt AgN3?
• What happens to a system at equilibrium if more reactant is added?
• What does buffer capacity depend on?
• If the plating current is doubled from 1.26 A to 2.52 A while depositing 2.08 g of copper, approximately how many minutes are required?
• At the eutectic point of a ternary system, which of the following is true?
• If the dissolution of CaF2 has Ksp = 4.0 × 10^−11 and the equilibrium [Ca^2+] = 1.0 × 10^−2 M, what is [F−] at equilibrium?
• Which expression represents Raoult's law for a solution with a volatile solvent and a nonvolatile solute?
• Precipitation will occur when the ionic product exceeds Ksp, causing the system to adjust until:
• State Hess's law in your own words.
• Which acid is the weakest in aqueous solution?
• For the reaction 2SO2 + O2 ⇌ 2SO3, when the pressure is increased, the forward rate increases and the yield of SO3 increases because the forward reaction reduces the total number of gas molecules. Which statement best explains this observation?
• The equation ΔG° = −RT ln K relates standard free energy change to what?
• Which statement regarding chemical reactions is true according to collision theory?
• In calorimetry, what does C_cal represent?
• How does increasing temperature affect the equilibrium constant K for endothermic and exothermic reactions?
• If Ke for the reaction 2SO3 (g) ⇌ 2SO2 (g) + O2 (g) is 2.3 x 10^-7, what is the equilibrium constant for the reverse reaction?
• In a strong acid–strong base titration, what is the pH at the equivalence point?
• What happens to the position of equilibrium for an exothermic reaction when the temperature is increased?
• Which expression gives the half-life of a first-order reaction?
• For the equilibrium Ni(CO)4 (g) ⇌ Ni(s) + 4 CO(g), what is the effect of increasing total pressure on the position of equilibrium?
• What current is required to plate 4.00 g copper in 60.0 minutes?
• The final yield of a reversible reaction is determined by:
• Which expression correctly describes the nonstandard Gibbs free energy change?
• If ΔH < 0 and ΔS > 0, what can be said about spontaneity across all temperatures?
• How can you determine reaction order from rate law data?
• What does the phase diagram triple point represent?
• In the reaction X2 (g) + 2Y(g) ⇌ 2Z (g). 12.00 moles of Z are placed in an evacuated 2.00-liter flask. After equilibrium, the flask contains 6.00 moles of Y. What is the equilibrium constant, K, for the reaction?
• Which statement about Kw is true?
• For a system in which Q equals K, what is true?
• Which condition indicates spontaneity at a given temperature according to ΔG?
• In electrolysis, how is the amount of substance produced at an electrode determined?
• A mixture contains 100 g of potassium dichromate, K2Cr2O7, and 200 g of water. The mixture is saturated at 60 °C and then cooled to 20 °C, allowing crystals to form. What mass of K2Cr2O7 crystallizes from the solution during cooling?
• The half-life for first-order radioactive decay of 32P is 14.3 days. How many days would be required for the activity to decrease to 20.0% of its initial value?
• If the equilibrium constant K for a reaction is much greater than 1, which statement is true about the equilibrium mixture?
• What is the general effect of increasing temperature on the solubility of most solid solutes in water?
• What is Kb of F-? Ka of HF is 6.8 × 10^-4
• In a 200 g sample of solution that is 89% by mass ethanol, what is the mole fraction of ethanol?
• Which statement about Le Châtelier's principle is true?