ACS General Chemistry 2 Practice Exam

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• Which factors determine boiling point elevation and freezing point depression for a given solute?
• Which expression correctly relates Gibbs free energy change to enthalpy and entropy at constant pressure and temperature?
• If ΔG = ΔH − TΔS, which statement is true when ΔG < 0 at a given temperature?
• Describe the general steps of an ICE table for the reaction aA + bB ⇌ cC + dD to find equilibrium concentrations.
• What is the difference between the reaction quotient Q and the equilibrium constant K?
• Which relation connects Gibbs free energy change and cell potential for a galvanic cell?
• Which constant equals approximately 96485 C/mol and relates electric charge to moles of electrons?
• Why doesn't a catalyst alter the final equilibrium composition?
• State Raoult's law for vapor pressures in a mixture of two volatile solvents.
• At a constant current of 1.26 A, how many grams of copper are deposited in 50.0 minutes?
• For a second-order reaction with a single reactant, the integrated rate law is which form?
• Le Chatelier's principle: how does increasing temperature affect an exothermic reaction's equilibrium?
• For an ideal gas expanding reversibly from volume V1 to V2 at constant temperature, which expression correctly gives ΔS?
• Which statement about solubility in a solution with a common ion is true?
• Which expression gives the half-life of a first-order reaction?
• Calculate the standard Gibbs free energy change at 298 K for the reaction FeO4 (s) + 4 CO (g) ⇌ 3 Fe (s) + 4 CO2 (g).
• What is the physical meaning of the Arrhenius pre-exponential factor A in k = A e^(−Ea/RT)?
• 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?
• Which law relates vapor pressure of a liquid mixture to the mole fraction of solvent in an ideal solution?
• Define buffer capacity and buffer range.
• What is the pH of a 0.10 M strong acid solution like HCl?
• What effect does a catalyst have on the activation energy and reaction rate?
• If the equilibrium constant K is much larger than 1, what can be said about ΔG° at that temperature?
• In a buffer solution near its pKa, the pH changes slowly with added acid or base, and pH is approximately equal to pKa when:
• In the equation m = (I t)/(n F) × M, what does F represent?
• Which statement correctly differentiates solubility from dissolution rate?
• If a binary alloy (C = 2) exists with two phases at fixed T and P, how many degrees of freedom F are allowed?
• What is the Ksp expression for MgCO3 in water?
• Which action increases the concentration of gas dissolved in a liquid?
• If the standard cell potential for a reaction is positive, the reaction is:
• Which statement regarding chemical reactions is true according to collision theory?
• What are the units of molality?
• Beta decay of an atom with atomic number 53 and mass number 131 yields a residual atom with which Z and A?
• Buffer capacity is influenced by concentration and pH relative to pKa. Which statement is true?
• For the equilibrium A ⇌ B with K = [B]/[A], what happens to [A] and [B] if more A is added?
• Lowering the pH (making the solution more acidic) has what effect on the solubility of metal hydroxides such as Fe(OH)3?
• Which statement is true about the relationship between Q and K at equilibrium?
• The equation ΔG° = −RT ln K relates standard free energy change to what?
• Le Châtelier's principle predicts that increasing pressure will shift equilibria toward the side with fewer moles of gas. This statement applies to...
• 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 condition indicates spontaneity at a given temperature according to ΔG?
• What is the expression for osmotic pressure in dilute solutions?
• What is the van't Hoff equation for osmotic pressure in dilute solutions?
• How many grams of copper are deposited in 60.0 minutes at 1.26 A?
• What is the overall balanced equation for the electrolysis of water in acidic solution?
• What is the mole fraction of water in 200 g of a solution that is 89% by mass ethanol (C2H5OH)?
• Which factor generally increases the solubility of sparingly soluble salts?
• When NH4NO3 dissolves in water, the temperature of the solution decreases. What describes the enthalpy change, entropy change, and which change drives the process?
• 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?
• What is the value of ΔG for a system at equilibrium?
• The final yield of a reversible reaction is determined by:
• For rate = k [H2] [NO]^2, if [H2] is doubled, the rate increases by what factor?
• What is the value of ΔG° when K = 1?
• At equilibrium, what is true about the rates of the forward and reverse reactions?
• Henry's law connects partial pressure of a gas with what property of the dissolved gas in the liquid?
• What is the mass of ethanol in the 200 g sample described above (89% by mass ethanol)?
• Which expression correctly describes the nonstandard Gibbs free energy change?
• Which acid is the weakest in aqueous solution?
• Which change will alter the value of Ksp for the salt AgN3?
• Which statement best describes colligative properties?
• Which statement correctly describes buffer capacity?
• In a multi-step reaction, what is the rate-determining step?
• Which statement is correct for the reaction below under standard conditions? 2Cl2 (g) + 2NO (g) → N2 (g) + 2Cl2O (g); ΔH° = -22.0 kJ/mol
• What is the general effect of increasing temperature on the solubility of most solid solutes in water?
• 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?
• For the equilibrium COCl2 (g) ⇌ CO (g) + Cl2 (g), what is the expression for Ke in terms of concentrations?
• During electrolysis of molten sodium iodide, what is the half-reaction occurring at the anode?
• How do you compute the standard cell potential E°cell from two half-reactions?
• 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?
• 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?
• How is the standard cell potential E°cell determined from half-cell potentials?
• Explain the common-ion effect and its impact on solubility.
• In electrolysis, how is the amount of substance produced at an electrode determined?
• What is the Arrhenius equation and how does temperature affect k?
• Which statement about the Arrhenius temperature dependence of the rate constant k is correct?
• How do you compute ΔHrxn° from standard enthalpies of formation?
• How does increasing total pressure affect the solubility of gases in liquids?
• If a gas-phase equilibrium A ⇌ B has Δn_gas = 0, what is the relationship between Kp and Kc?
• In a buffer where [A−] equals [HA], what is pH relative to pKa?
• Which statement about Kw is true?
• What is the integrated rate law for a first-order reaction?
• What is a concentration cell?
• In a weak acid–strong base titration, the pH at the equivalence point is
• If a solute does not dissociate in solution, its van't Hoff factor i is approximately
• What thermodynamic criterion determines spontaneity of a process at constant temperature and pressure?
• 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?
• At constant volume, the change in internal energy is equal to which of the following?
• 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)
• If the equilibrium constant K for a reaction is much greater than 1, which statement is true about the equilibrium mixture?
• Which statement best describes osmotic pressure?
• What is the correct statement about the autoionization of water at 25°C?
• 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?
• What is the relationship between the equilibrium constant K and the reaction quotient Q?
• Which half-life expression is correct for a zero-order reaction?
• For a first-order reaction, the half-life t1/2 is related to k by which expression?
• In the electrolysis of molten sodium iodide, which species is oxidized at the anode?
• In constant-pressure calorimetry, for an endothermic reaction, which statement about qrxn and qcal is true?
• What does the van't Hoff factor i account for in colligative properties?
• When comparing Q and Ksp for an unsaturated solution, which statement is correct?
• For a system in which Q equals K, what is true?
• What is the overall order of the reaction for rate = k [H2] [NO]^2?
• 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°?
• 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?
• In a phase diagram, what does the line between two phases represent?
• What is Kw and its value at 25°C?
• For a spontaneous galvanic cell, what is the sign of ΔG?
• What is the Clapeyron equation and what does it relate?
• If a reaction has ΔH < 0 and ΔS > 0, the process is spontaneous:
• Which statement correctly describes a galvanic cell with a positive standard cell potential E°cell?
• State the Nernst equation for a half-cell reaction at 25°C.
• Which statement best describes how to determine entropy-driven versus enthalpy-driven using ΔG = ΔH − TΔS?
• How does complex formation with ligands affect solubility of a sparingly soluble salt?
• What happens to the position of equilibrium for an exothermic reaction when the temperature is increased?
• 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?
• If ΔH < 0 and ΔS > 0, what can be said about spontaneity across all temperatures?
• If Q is the reaction quotient and K is the equilibrium constant, which statement is true when Q < K?
• In a concentration cell with identical electrodes, what is the emf when the ion concentrations are equal on both sides?
• Which expression represents the first law of thermodynamics in terms of ΔU, q, and w?
• 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 rate law is correct for the reaction 2H2 (g) + 2NO (g) → N2 (g) + 2H2O (g)?
• For an endothermic dissolution process, what is the typical effect of increasing temperature on the solubility and Ksp?
• Which expression represents the Nernst equation at 25°C for a cell reaction that transfers n electrons?
• 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 does the phase diagram triple point represent?
• What happens at the critical point on a phase diagram?
• 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?
• In the proposed mechanism for NO2 + F2 reaction, which step is rate-determining?
• What is the Gibbs phase rule for a system with C components and P phases at fixed temperature and pressure? F = ?
• What happens to a system at equilibrium if more reactant is added?
• Which statement about spontaneity and ΔG = ΔH − TΔS is true?
• Which change is most likely to be accompanied by an increase in entropy?
• For a reaction where K > 1 at all temperatures, which statement(s) must be true?
• Which describes the conjugate acid of NH3?
• In acidic solution, the half-reactions during electrolysis of water are:
• What are ΔHfus and ΔHvap?
• If a saturated solution of MgCO3 is placed in contact with a large supply of Mg2+ ions, what happens to its solubility?
• How can you determine reaction order from rate law data?
• Gas solubility generally increases when temperature decreases. Which option correctly identifies this statement?
• If the standard cell potential E° is positive, what is the sign of ΔG°?
• In a ternary eutectic system, what occurs at the eutectic point?
• 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?
• State Raoult's law for an ideal solution.
• Which statement correctly describes Raoult's law and Henry's law?
• 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?
• In copper plating from a Cu2+-containing solution, which half-reaction occurs at the cathode?
• For a reaction with Q > K, which direction will the reaction proceed?
• Which term describes the cell potential measured when no current flows (open-circuit condition)?
• If a nonvolatile solute is added to a solvent, what happens to the freezing point?
• 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?
• Do catalysts change the position of chemical equilibrium?
• Colligative properties depend on which characteristic of solute particles?
• Which information is used to determine the order of a reaction with respect to a given species from rate data?
• According to the Arrhenius equation, what is the effect of increasing temperature on the rate constant k when Ea > 0?
• The standard Gibbs free energy change ΔG° is related to standard cell potential E° by which equation?
• 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?
• Which expression correctly approximates the pH of a dilute solution of a monoprotic weak acid with concentration C and Ka?
• Distinguish between solubility and dissolution rate; how does temperature typically affect each for a salt?
• 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?
• In beta decay, what happens to the mass number A?
• In the dissolution of Ca(OH)2, the hydroxide ion appears to the power of what in the Ksp expression?
• Which statement about Le Châtelier's principle is true?
• 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?
• In beta decay, what happens to the atomic number Z?
• In a concentration cell, increasing the concentration difference between the two half-cells has what effect on the cell emf?
• For the concentration cell Fe(s) | Fe3+ (0.100 M) || Fe3+ (1.00 M) | Fe(s) at 25 C, what is Ecell in millivolts?
• Write the Ksp expression for AB(s) ⇌ A+(aq) + B−(aq).
• Which equation correctly relates standard Gibbs free energy change to the equilibrium constant at a given temperature?
• 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?
• An acetate buffer is prepared with 0.100 M HOAc and 0.100 M NaOAc. If pKa(HOAc) = 4.74, what is the pH?
• The mass of copper deposited by electrolysis is proportional to which of the following?
• For a zero-order reaction, the integrated rate law is which expression?
• 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?
• For the dissolution of BaSO4(s) ⇌ Ba^2+(aq) + SO4^2−(aq), if the solubility is s, which expression gives Ksp?
• Write the Ksp expression for Ca(OH)2(s) ⇌ Ca2+(aq) + 2 OH−(aq).
• In rate law rate = k[A]^m[B]^n, the exponents m and n represent what?
• Which anion is the most basic?
• At the eutectic point of a ternary system, which of the following is true?
• Write the solubility product expression for PbSO4(s) ⇌ Pb2+(aq) + SO4^2−(aq) and interpret Ksp.
• State Henderson-Hasselbalch equation and its common-use scenario.
• What is the basic operating principle of a galvanic (electrochemical) cell?
• What defines a concentration cell and its emf?
• In Henry's law S = k_H p, with S in mol/L and p in atm, what are the units of k_H?
• 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.
• Why does Fe(OH)3 solubility increase under acidic conditions?
• Which expression represents Raoult's law for a solution with a volatile solvent and a nonvolatile solute?
• Describe the common method to balance redox reactions in acidic solution.
• If the initial-rate data show that doubling [A] while keeping [B] constant doubles the rate, what is the order with respect to A?
• Which 0.1 molal aqueous solution will have the lowest freezing point?
• One Faraday equals how many coulombs?
• 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?
• Which statement about hydrolysis of salts is correct?
• In calorimetry, what does C_cal represent?
• At the equivalence point of a weak acid-strong base titration, the pH is:
• In Ni(CO)4 (g) ⇌ Ni(s) + 4 CO (g), why is the activity of Ni(s) not included in the equilibrium expression?
• What volume (in mL) of 0.150 M NaOH (aq) is required to neutralize 25.0 mL of 0.100 M H2SO4 (aq)?
• 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?
• Which statement about the cathode in a galvanic cell is true?
• What current is required to plate 4.00 g copper in 60.0 minutes?
• What is the atomic number of iodine?
• Which substance dissolves in water to produce an acidic solution?
• If reaction quotient Q equals 1, what is ΔG relative to ΔG°?
• In a reaction mechanism, what is the steady-state approximation?
• What is the pH at the equivalence point for a strong acid-strong base titration?
• In a pressure–volume system, which type of work is zero when the volume is held constant?
• 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?
• 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
• 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?
• How does increasing temperature affect the equilibrium constant K for endothermic and exothermic reactions?
• How does a catalyst affect a reaction's activation energy and rate?
• What is the standard Gibbs free energy change for the formation of one mole of ammonia from its elements under standard conditions?
• At constant pressure, heat flow equals which thermodynamic quantity?
• 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)
• 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)?
• 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 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?
• State Hess's law in your own words.
• 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?
• For dissolution endothermic with positive ΔS, how does ΔG° change with increasing temperature?
• Precipitation will occur when the ionic product exceeds Ksp, causing the system to adjust until:
• 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 Henry's law and when is it applicable?
• 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'?
• Which of the following are colligative properties?
• 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
• How does formation of a complex ion affect the solubility of a sparingly soluble salt?
• In the gas-phase equilibrium 2BrCl(g) ⇌ Br2(g) + Cl2(g), what happens if the container volume is decreased (pressure increased) at constant temperature?
• What is the pH of a 0.820 M aqueous ammonia solution? Ka? Kb (NH3) = 1.8 × 10^-5
• 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)?
• A nonvolatile solute is added to a volatile solvent. According to Raoult's law, the solvent's vapor pressure:
• In a strong acid–strong base titration, what is the pH at the equivalence point?
• 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?
• Standard reduction potentials can be used to judge spontaneity of a redox reaction by:
• Which statement best describes how the observed rate law is determined in a mechanism?
• What does buffer capacity depend on?
• 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: