CHEM 112 Final Exam Study Guide Questions And Accurate Answers

For a reaction, what generally happens if the temperature is decreased? - correct answers A decrease in k occurs, which results in a slower rate. Define Le Chatelier's Principle. - correct answers When a chemical system at equilibrium is disturbed, the system shifts in a direction that minimizes the disturbance. Give the characteristic of a second-order reaction having only one reactant. - correct answers The rate of the reaction is proportional to the square of the concentration of the reactant. The equilibrium constant is given for one of the reactions below. Determine the value of the missing equilibrium constant. 2 SO 2( g) + O 2( g) ⇌ 2 SO 3( g) K c = 1.7 × 10 6 SO 3( g) ⇌ 1/2 O 2( g) + SO 2( g) K c = ? - correct answers 7.7 × 10 -4 Calculate P (NO) eq, if P (NOCl) eq = 0.35 atm, P (Cl 2)eq = 0.40 atm, and K p = 1.9 × 10 -2. 2 NOCl( g) ⇌ 2 NO( g) + Cl 2( g) - correct answers 0.076 atm The first-order decomposition of cyclopropane has a rate constant of 6.7 × 10 -4 s -1. If the initial concentration of cyclopropane is 1.33 M, what is the concentration of cyclopropane after 644 s? - correct answers 0.86 M In a reaction mixture containing reactants and products, each at a concentration of 1M, what is the value of Q? - correct answers 1 The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.34 M. What is the rate constant for this reaction? - correct answers 1.9 × 10 -1 M -1s -1 Consider the following reaction at equilibrium. What effect will decreasing the temperature have on the system? C 3H 8( g) + 5 O 2( g) ⇌ 3 CO 2( g) + 4 H 2O( l) ΔH° = -2220 kJ - correct answers The reaction will shift to the right in the direction of products. Consider the following reaction at equilibrium. What will happen if the volume decreased? 4 FeS 2( s) + 11 O 2( g) ⇌ 2 Fe 2O 3( s) + 8 SO 2( g) - correct answers The equilibrium will change in the direction of the products. Given the following proposed mechanism, predict the rate law for the overall reaction. A 2 + 2 B → 2 AB (overall reaction) Mechanism A 2 ⇌ 2 A fast A + B → AB slow - correct answers Rate = k[A 2] 1/2[B] Define dynamic equilibrium. - correct answers the rate of the forward reaction equals the rate of the reverse reaction The first-order rearrangement of CH 3NC is measured to have a rate constant of 3.61 × 10 -15 s -1 at 298 K and a rate constant of 8.66 × 10 -7 s -1 at 425 K. Determine the activation energy for this reaction. - correct answers 160 kJ/mol If Q K, it means.... - correct answers The reverse reaction will proceed to form more reactants. A rate is equal to 0.0200 M/s. If [A] = 0.100 M and rate = k[A] 0, what is the new rate if the concentration of [A] is increased to 0.400 M? - correct answers 0.0200 M/s What is the conjugate acid of HSO 3⁻ ? - correct answers H2SO3 Determine the molar solubility of AgBr in a solution containing 0.120 M NaBr. K sp (AgBr) = 7.7 × 10 -13. - correct answers 6.4 × 10 -12 M Which of the following solutions would have the highest pH? Assume that they are all 0.10 M in acid at 25 ∘C. The acid is followed by its K a value. - correct answers HC6H5O, 1.3 × 10-10 A Lewis base - correct answers donates a pair of electrons Calculate the pH of a buffer that is 0.225 M HC 2H 3O 2 and 0.162 M KC 2H 3O 2. The K a for HC 2H 3O 2 is 1.8 × 10 -5. - correct answers 4.60 If the pKa of HCHO 2 is 3.74 and the pH of an HCHO 2/NaCHO 2 solution is 3.74, which of the following is TRUE? - correct answers [HCHO2] = [NaCHO2] Determine the pH of a 0.188 M NH 3 solution at 25°C. The K b of NH 3 is 1.76 × 10 -5. - correct answers 11.260 Place the following in order of increasing acid strength. HBrO 2 HBrO 3 HBrO HBrO 4 - correct answers HBrO HBrO2 HBrO3 HBrO4 The Brønsted-Lowry model focuses on the transfer of ________ in an acid-base reaction. - correct answers H+ Determine the pH of a 0.22 M NaF solution at 25°C. The K a of HF is 3.5 × 10 -5. - correct answers 8.90 Give the characteristics of a strong acid. - correct answers -deprotonates/ionizes completely in aqueous solutions -has equilibrium far to the right -has a polar bond -has a weaker bond to hydrogen A solution containing AgNO 3 is mixed with a solution of NaCl to form a solution that is 0.10 M in AgNO 3 and 0.075 M in NaCl. What will happen once these solutions are mixed? Ksp (AgCl) = 1.77 × 10 -10. - correct answers Silver chloride will precipitate out of solution, leaving a saturated AgCl solution. Which of the following bases is the weakest? The base is followed by its K b value. - correct answers C5H5N, 1.7 × 10-9 When titrating ammonia with a hydrochloric acid at 25°C, the - correct answers pH will be less than 7 at the equivalence point. A 700.0 mL sample of 0.18 M HClO 4 is titrated with 0.27 M CsOH. Determine the pH of the solution after the addition of 350.0 mL of CsOH. - correct answers 1.52 Determine the solubility of the ions that is calculated from the Ksp for Na 2CO 3. - correct answers 4s^3 Determine the [H 3O⁺] in a 0.265 M HClO solution. The K a of HClO is 2.9 × 10 -8. - correct answers 8.8 × 10-5 M Place the following in order of decreasing metallic character. Sn Te Sb I - correct answers Sn Sb Te I Paramagnetic: - correct answers When an unpaired electron is attracted by an external magnetic field. Choose the electron configuration for Zr 2+. - correct answers [Kr]4d2 Use Standard Reduction Potential Table to determine which of the following is the best oxidizing agent. - correct answers MnO 4- In an electrolytic cell, the anode is defined as - correct answers the positive terminal of the power source. How many electrons are transferred in the following reaction? (The reaction is unbalanced.) F 2( s) + Fe( s) → Fe 3+( aq) + F⁻( aq) - correct answers 6 Balance the following redox reaction if it occurs in basic solution. What are the coefficients in front of ClO 2 and H 2O in the balanced reaction? H 2O 2( l) + ClO 2( aq) → ClO 2⁻( aq) + O 2( g) - correct answers ClO 2 = 2, H 2O = 2 How many moles of aqueous ions will be produced from the dissolution of 1.0 mole of Li 3[FeCl 6] in water? - correct answers 4 Place the following in order of increasing standard molar entropy. N 2O 4( g) NO( g) NO 2( g) - correct answers NO NO2 N2O4 Based on the half-reactions and their respective standard reduction potentials below, the strongest reducing agent is ________, and the strongest oxidizing agent is ________. Ag +( aq) + e - → Ag( s) 0.80 V 2 H +( aq) + 2 e - → H 2( g) 0.00 V Cd 2+( aq) + 2 e - → Cd( s) -0.40 V - correct answers Cd, Ag+ Identify the process that is spontaneous. - correct answers Iron rusting Which of the following reactions will have the largest equilibrium constant (K) at 298 K? - correct answers 2 Hg(g) + O2(g) → 2 HgO(s) ΔG° = -180.8 kJ An exothermic reaction is a process that - correct answers has a negative ΔH sys and a positive ΔS surr. Which of the following relationships is correct at constant T and P? - correct answers ΔG is proportional to -ΔSuniv Which of the following can function as a bidentate ligand? - correct answers C 2O 4 2- Entropy is a measure of - correct answers molecular randomness To prevent rust, nails are coated with - correct answers Zinc