chem 106 final exam
In response to external temperature, vanadium(IV) oxide (VO2) undergoes a reversible metal→insulator phase transition at 67°C, making the said material attractive for "smart" window thermochromic coatings and memristors, to name a few applications (Alivio, T. E. G., et al. Chemistry of Materials. 2017, 29, 5401-5412). What is the oxidation state of V in VO2? a. +2 b. -2 c. -4 d. +4
+4
Consider the freezing of liquid water at -24°C. For this process what are the signs for ΔH, ΔS, and ΔG? ΔH ΔS ΔG a. - + - b. + - + c. - - - d. + - -
- - -
What is ΔG° for the following electrochemical equation? (E°red(K+/K) = -2.931 V, E°red(Ca2+/Ca) = - 2.868 V) 2K(s) + Ca2+(aq) → 2K+(aq) + Ca(s) a. -24 kJ/mol b. -12 kJ/mol c. -6 kJ/mol d. 12 kJ/mol
-12 kJ/mol
What is ΔG° at 298 K for the following equilibrium? Ag+(aq.) + 2NH3(aq.) ⇌ Ag(NH3)2+(aq.); K = 1.7 × 107 at 298 K a. -18 kJ b. 41 kJ c. 0 d. -41 kJ
-41 kJ
Given the following, determine ΔG° at 298 K for the precipitation reaction, Ag+(aq) +Br−(aq) → AgBr(s) Substance. ΔG°f (kJ/mol) at 298 K Br−(aq) -104.0 Ag+(aq) 77.12 AgBr(s) -96.9 a.-70.0 kJ/mol b. 123.8 kJ/mol c. 84.2 kJ/mol d. -123.8 kJ/mol
-70.0 kJ/mol
For the hypothetical reaction A → products, the concentration of A was monitored with time. From the following graph, what is the rate constant for the decomposition of A? a. 0.07238 M-1 s-1 b. -0.07238 M-1 s-1 c. -10.00 M-1 s-1 d. 10.00 M-1 s-1
0.07238 M-1 s-1
In which of these solutions would silver(I) carbonate have the lowest molar solubility? For silver(I) carbonate, Ksp = 8.5 × 10-12. a. 0.1 M HNO3 b. 0.1 M KOH c. 0.1 M HCl d. 0.1 M AgNO3
0.1 M AgNO3
Assume an indicator works best when the equivalence point of a titration comes in the middle of the indicator range. For which of the following titrations would methyl red be the best indicator? The pH range of methyl red is 4.8 to 6.0. a. 0.100 M HNO3 + 0.100 M KOH b. 0.100 M HF (Ka = 7.2 × 10-4) + 0.100 M NaOH c. 0.100 M NH3 (Kb = 1.8 × 10-5) + 0.100 M HCl d. 0.100 M acetic acid (Ka = 1.8 × 10-5) + 0.100 M NaOH
0.100 M NH3 (Kb = 1.8 × 10-5) + 0.100 M HCl
Which of the following solutions has the lowest boiling point?a. 0.15 M Na2S b. 0.20 M C2H6O2 c. 0.15 M Ba(NO3)2 d. 0.10 M CaBr2
0.20 M C2H6O2
What is E of the following cell reaction at 25°C? Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s); E°cell = 0.460 V [Cu2+] = 0.017 M, [Ag+] =0.17 M a. 0.460 V b. 0.476 V c. 0.467 V d. 0.282 V
0.467 V
Determine the standard potential, E°, of a cell that employs the reaction: Fe+Cu2+ →Cu+Fe2+. Reaction E° (volts) Fe2+ + 2e- → Fe -0.435 Cu2+ + 2e- → Cu +0.340 a. 0.775 b. -0.775 c. -0.095 d. 0.095
0.775
What is the pH of a 0.072 M HClO4 solution? a. 12.86 b. 15.14 c. 1.14 d. 2.63
1.14
The molar solubility of PbI2 is 1.47 × 10-3 M. Calculate the value of Ksp for PbI2. a. 4.32 × 10^-6 b. 3.18 × 10^-9 c. 1.27 × 10^-8 d. 1.47 × 10^-3
1.27 × 10^-8
A 50.00-mL sample of 0.100 M KOH is titrated with 0.171 M HNO3. Calculate the pH of the solution after 52.00 mL of HNO3 is added. a. none of these b. 1.42 c. 1.06 d. 12.58
1.42
Find the solubility (in mol/L) of lead(II) chloride, PbCl2, at 25°C. Ksp = 1.57 × 10-5. a. 1.58 × 10^-2 b. 2.50 × 10^-2 c. 1.98 × 10^-3 d. 6.05 × 10^-17
1.58 × 10^-2
If Ka for HCN is 6.15 × 10-10, what is Kb for CN-? a. 1.63 × 10-5 b. None of these are correct. c. 6.15 × 104 d. 6.15 × 10-24
1.63 × 10^-5
A first-order chemical reaction is observed to have a rate constant of 22 min-1. What is the corresponding half-life for the reaction? Note: 1 min = 60 s a. 1.9 min b. 2.7 s c. 1.9 s d. 32 min
1.9 s
In response to external temperature, vanadium(IV) oxide (VO2) undergoes a reversible metal→insulator phase transition at 67°C. The introduction of boron atoms into the lattice of VO2 nanowires modulates the metal→insulator transition temperature of VO2 close to room temperature values (Alivio, T. E. G., et al. Chemistry of Materials. 2017, 29, 5401-5412; Sellers, D. G., et al. Journal of the American Chemical Society. 2020, 142, 15513-15526; and Yano, A., et al. Journal of Physical Chemistry C. 2020, 124, 21213-21221), thus making VO2 an attractive material for "smart window" coatings. The transition temperature is further attenuated as more B atoms are introduced. It has been found that the introduction of B atoms is accelerated the smaller the length of the nanowires are (in other words, higher surface area). Which of the following VO2 nanowires increases the rate of B introduction the most? a. 100 nm b. 150 nm c. 200 nm d. 250 nm
100 nm
Walter White asks Jesse Pinkman: What is the pH of a 0.35 M aqueous solution of methylamine, (CH3NH2)? Help him with the math, knowing that the Kb of methylamine is 4.4 x 10-4. a. 1.92 b. 12.08 c. 13.24 d. 10.00
12.08
Find the mass percent of CaCl2 (110.98 g/mol) in an aqueous solution whose molarity is 1.45 M and whose density is 1.12 g/mL. a. 16.1% b. 14.4% c. 16.8% d. 85.6%
14.4%
Consider the equilibrium reaction 2N2(g) + O2(g) ⇌ 2N2O(g). In a particular experiment, the equilibrium concentration of N2 is 0.048 M, of O2, 0.093 M, and of N2O, 6.55 × 10−21 M. What is the value of the equilibrium constant K? a. 5.0 × 10^36 b. 2.2 × 10^−36 c. 3.1 × 10^−17 d. 2.0 × 10^−37
2.0 × 10^−37
For weak acid, HX, Ka = 4.4 x 10-5. Calculate the pH of a 0.32 M solution of HX. a. 2.43 b. 0.49 c. 11.57 d. 4.85
2.43
Given the following, determine S° at 298 K for one mole of NO(g). 2NO(g) + O2(g) → 2NO2(g); ΔS° = −146.7 J/K at 298K Substance S° (J/(mol ∙ K)) at 298 K NO(g). ? O2(g) 205.1 NO2(g). 240.0 a. 210.9 J/K b. −90.85 J/K c. 421.7 J/K d. -421.7 J/K
210.9 J/K
What mass of chromium (52.00 g/mol) could be deposited by electrolysis of an aqueous solution of Cr2(SO4)3 for 145 min using a constant current of 15.0 A? (F = 96485 C/mol e-) a. 0.187 g b. 0.391 g c. 23.4 g d. 211.0 g
23.4 g
When a 41.1-g sample of an unknown nonelectrolyte is dissolved in 500.g of benzene, the freezing point of the resulting solution is 3.77°C. The freezing point of pure benzene is 5.48°C and Kf for benzene is 5.12°C/m. Calculate the molar mass of the unknown compound. a. 492 g/mol b. 24.0 g/mol c. 123 g/mol d. 246 g/mol
246 g/mol
A second-order reaction starts with an initial concentration of 0.100 M of the reactant. If the rate constant is 3.8× 10-2 M-1 s-1, what is the time required to decrease the initial concentration to 0.050 M? a. 260 s b. 18.2 s c. 1.32 s d. 390 s
260 s
In which of the following reactions does a decrease in the volume of the reaction vessel at constant temperature favor formation of the products? a. NO2(g) + CO(g) ⇌ NO(g) + CO2(g) b. H2(g) + I2(g) ⇌ 2HI(g) c. 2O3(g) ⇌ 3O2(g) d. 2H2(g) + O2(g) ⇌ 2H2O(g)
2H2(g) + O2(g) ⇌ 2H2O(g)
The solubility product for lanthanum fluoride (LaF3, 195.90 g/mol) is 2.0 × 10-19. What is the solubility of this compound (in g/L) in a solution that contains 0.010 M NaF? a. 3.9 × 10^-11 b. 2.0 × 10^-19 c. 2.0 × 10^-13 d. 1.8 × 10^-3
3.9 × 10^-11
At the normal boiling point of benzene, ΔH°vap = 30.7 kJ/mol and ΔS°vap = 86.9 J/(mol ∙ K). What is the normal boiling point of benzene? a. 869 K b. 373 K c. 267 K d. 353 K
353 K
A solution is made with [Pb2+] = 2.5 × 10-3 M and [I-] = 4.0 × 10-3 M. What is the reaction quotient, Qsp, for the dissolution of PbI2 in water? Do you expect PbI2 to precipitate? Ksp of PbI2 = 6.5 × 10-4 a. 2.8 × 10-8, no precipitate will form b. 4.0 × 10-8, no precipitate will form c. 1.1 × 10-4, yes a precipitate will form d. 2.5 × 10-3, yes a precipitate will form
4.0 × 10-8, no precipitate will form
Consider the following equilibrium 2NOCl(g) ⇌ 2NO(g) + Cl2(g) with K = 1.6 × 10-5. Initially, only 1.00 mole of pure NOCl and 0.933 mole of pure Cl2 are placed in a 1.00-L container. Calculate the equilibrium concentration of NO(g). Hint: you do not need to use the quadratic formula for this problem. a. 0.935 M b. 4.14 × 10-3 M c. 1.6 × 10-5 M d. 0.468 M
4.14 × 10-3 M
What is the pH of a solution that is 0.048 M in HA and also 0.0032 M in NaA? (Ka = 4.1 × 10-6) a. 8.06 b. 7.76 c. 5.39 d. 4.21
4.21
Determine the percent dissociation of a 0.17 M solution of hypochlorous acid, HClO. The Ka for the acid is 3.5 × 10-8. a. 4.5 × 10-2 % b. 3.5 × 10-6 % c. 1.1 × 10-2 % d. 6.0 × 10-9 %
4.5 × 10-2 %
What is the pH of a 23.91 mL solution that contains 0.25 m (molal) benzoic acid, C6H5COOH, and 0.75 m sodium benzoate, NaC6H5COO? (Ka of benzoic acid = 6.3 × 10-5) a. 10.28 b. 9.32 c. 6.35 d. 4.68
4.68
The correct mathematical expression for finding the molar solubility (s) of Sn(OH)2 is: a. 4s3 = Ksp b. 2s2 = Ksp c. 108s5 = Ksp d. 2s3 = Ksp
4s3 = Ksp
For the reaction H2(g) + Cl2(g) ⇌ 2HCl(g), K = 5.14 × 1025 at a temperature of 391 K. What is KP at this temperature? a. 1.60 × 10^24 b. 1.65 × 10^27 c. 5.14 × 10^25 d. 5.30 × 10^28
5.14 × 10^25
The vapor pressure of pure water at 15 °C is 12.8 mm Hg. What is the equilibrium vapor pressure of water above a mixture of 72.0 g ethanol (CH3CH2OH, molar mass = 46.07 g/mol) and 22.0 g water (molar mass = 18.016 g/mol)? a. 7.19 mm Hg b. 12.8 mm Hg c. 5.61 mm Hg d. 2.84 mm Hg
5.61 mm Hg
For the reaction IO3-(aq.) + 5I-(aq.) + 6H+(aq.) → 3I2(aq.) + 3H2O(l) the rate of disappearance of IO3-(aq.) at a particular time and concentration is 2.0× 10-3 M/s. What is the rate of appearance of I2(aq.)? a. 6 × 10-3 M/s b. 6.7 × 10-3 M/s c. -6 × 10-3 M/s d. 2 × 10-3 M/s
6 × 10-3 M/s
What is the pH of a 0.48 M KCl solution? a. 0.32 b. 9.20 c. 7.00 d. 2.40
7.00
Given 100.0 mL of a buffer that is 0.50 M in HOCl and 0.74 M in NaOCl, what is the pH after 10.0 mL of 1.0 M NaOH has been added? (Ka for HOCl = 3.5 × 10-8) a. 7.13 b. 7.78 c. 7.66 d. 7.46
7.78
Calculate the osmotic pressure of 6.00 L of an aqueous 0.972 M solution of magnesium chloride at 30.°C.Assume that magnesium chloride fully dissociates in solution a. 72.5 atm b. 24.5 atm c. 43.0 atm d. 9.54 × 10-2 atm
72.5 atm
For which of the following salts would the addition of nitric acid increase its solubility? a. AgCN b. AgI c. AgCl d. AgNO3
AgCN
Which of the following linear chain alcohols is likely to have the highest standard entropy in the liquid state? a. CH3CH2CH2CH2CH2OH b. CH3CH2OH c. CH3CH2CH2OH d. CH3CH2CH2CH2OH
CH3CH2CH2CH2CH2OH
Which of the following salts forms an acidic aqueous solution? a. NaCN b. CH3NH3Cl c. KCH3CO2 d. RbBr
CH3NH3Cl
Which of the following transformations represents an increase in the entropy of the system? a. N2 (gas , 434 K) → N2 (gas, 217 K) b. Fe (liquid) → (solid) c. C5H12 (gas) → C5H12 (liquid) d. CH4 (9.94 L) → CH4 (19.9 L)
CH4 (9.94 L) → CH4 (19.9 L)
Given the following acids and Ka values: HClO4 HCH3COO HCN HF 1 × 107 1.76 × 10-5 4.93 × 10-10 3.53 × 10-4 What is the order of increasing base strength? a. ClO4- < F- < CH3COO- < CN- b. CN- < F- < CH3COO- < ClO4- c. CN- < ClO4- < F- < CH3COO- d. CN- < CH3COO- < F- < ClO4-
ClO4- < F- < CH3COO- < CN-
Which of the following pairs of substances can be used to make a buffer solution? a.NaI and HI b. Li2HPO4 and H3PO4 c. KBr and HBr d. CsF and HF
CsF and HF
A weak acid, HF, is in solution with dissolved sodium fluoride, NaF. If HCl is added, which ion will react with the extra hydrogen ions from the HCl to keep the pH from changing? a. none of these b. F- c. OH- d. Na-
F-
For which of the following reactions is ΔS° > 0 at 25°C? a. 2Li(s) + O2(g) → Li2O(s) b. 2H2(g) + O2(l) → 2H2O(l) c. 2CO(g) + O2(g) → 2CO2(g) d. F3BNH3(s) → BF3(g) + NH3(g)
F3BNH3(s) → BF3(g) + NH3(g)
Blood is buffered by the carbonic acid/bicarbonate buffer system (H2CO3/HCO3-). If the pH of the blood starts to rise (for example if your kidneys fail to metabolize urea properly) which component of the buffer system will react to maintain the correct pH? a. HCO32- b. H2CO3 c. CO32- d. H2O
H2CO3
Which is the strongest acid of the following? a. HOAt b. HClO2 c. HClO d. HIO
HClO2
Which of the following 1.0 M aqueous solutions contains the strongest acid? a. HF (Ka = 7.2 × 10-4) b. HC2H3O2 (Ka = 1.8 × 10-5) c. HOCl (Ka = 3.5 × 10-8) d. H2C6H6O6 (Ka1 = 7.9 × 10-5, Ka2 = 1.6 × 10-12).
HF (Ka = 7.2 × 10-4)
Rank the following metal sulfides in order of increasing molar solubility in water. a. MnS < FeS < CoS < CuS < HgS b. FeS < HgS < CoS < CuS < MnS c. HgS < CuS < CoS < FeS < MnS d. CuS < CoS < FeS < MnS < HgS
HgS < CuS < CoS < FeS < MnS
Rank the following compounds according to increasing solubility in water. I. CH3-CH2-CH2-CH3 II. CH3-CH2-O-CH2-CH3 III. CH3-CH2-OH IV. CH3-OH a. III < IV < II < I b. I < III < IV < II c. I < II < IV < III d. I < II < III < IV
I < II < III < IV
A liquid-liquid solution is called an ideal solution if: I. It obeys PV = nRT. II. It obeys Raoult's law. III. Solute-solute, solvent-solvent, and solute-solvent interactions are very similar. IV. Solute-solute, solvent-solvent, and solute-solvent interactions are quite different. a. I, II, III b. II, III c. I, III, IV d. I, II, IV
II, III
Formation of a solution where the process is endothermic can take place provided that: a. Anions and cations are not involved. b. Anions and cations are involved. c. It is accompanied by an increase in disorder. d. It is accompanied by an increase in order.
It is accompanied by an increase in disorder.
When cobalt chloride is added to pure water, the Co2+ ions hydrate. The hydrated form then reacts with the Cl- ions to set up the equilibrium shown here: Co(H2O)62+ + 4Cl- ⇌ CoCl42- + 6H2O (pink) (blue) Which statement describes the change that the system will undergo if chloride ions are added? a. The silver ion will react with the CoCl42-. b. Nothing will change. c. It should become more pink. d. It should become more blue.
It should become more blue.
What is the solubility product expression for Zn3(PO4)2? a. Ksp = [Zn2+]3[PO43-]2 b. Ksp = [Zn32+][(PO43-)2] c. Ksp = [3Zn2+]3[2PO43-]2 d. Ksp = [Zn2+][2PO43-]
Ksp = [Zn2+]3[PO43-]2
Which of the following is the best reducing agent? Cl2 +2e- →2Cl- E°=1.36V Mg2+ +2e- →Mg E°=-2.37V 2H+ +2e- →H2 E°=0.00V a. Cl2 b. Mg c. Mg2+ d. H2
Mg
Which of the following is the strongest oxidizing agent? MnO4- +4H+ +3e- →MnO2 +2H2O E° = 1.68 V I2 +2e- →2I- E° = 0.54 V Zn2+ + 2e- → Zn E° = -0.76 V a. MnO4- b. I2 c. Zn2+ d. Zn e. MnO2
MnO4-
Balance the following oxidation-reduction occurring in acidic solution. MnO4-(aq) + Co2+(aq)→ Mn2+(aq) + Co3+(aq) a. MnO4-(aq) + 4H2(g) + 5Co2+(aq)→ Mn2+(aq) + 4H2O(aq) + 5Co3+(aq) b. MnO4-(aq) + 8H+(aq) + Co2+(aq) → Mn2+(aq) + 4H2O(aq) + Co3+(aq) c. MnO4-(aq) + 8H+(aq) + 2Co2+(aq) → Mn2+(aq) + 4H2O(aq) + 2Co3+(aq) d. MnO4-(aq) + 8H+(aq) + 5Co2+(aq) → Mn2+(aq) + 4H2O(aq) + 5Co3+(aq)
MnO4-(aq) + 8H+(aq) + 5Co2+(aq) → Mn2+(aq) + 4H2O(aq) + 5Co3+(aq)
The compound ammonia, NH3, is a weak base when dissolved in water. Which of the following is the correct equation for the reaction of ammonia in water? a. NH3(aq.) + H2O(l) ⇌ NH4+(aq.) + OH−(aq.) b. NH3(aq.) + H2O(l) ⇌ NH2−(aq.) + H3O+(aq.) c. NH3(aq.) + H2O(l) ⇌ NH2−(aq.) + H3O+(aq.) d. NH3(aq.) + OH−(aq.) ⇌ NH2−(aq.) + H2O(l)
NH3(aq.) + H2O(l) ⇌ NH4+(aq.) + OH−(aq.)
Consider the reaction HNO2(aq) + H2O(l) ⇌ H3O+(aq) + NO2-(aq). Which species is the conjugate base of HNO2? a. NO2-(aq) b. H3O+(aq) c. H2NO2+(aq) d. H2O(l)
NO2-(aq)
For which of the following will precipitation be expected? a. Qc = 1 b. Qc > Ksp c. Qc = Ksp d. Qc < Ksp
Qc > Ksp
A proposed mechanism for the decomposition of N2O5 is as follows: N2O5 NO2 + NO3 slow step NO2 + NO3 NO2 + O2 + NO fast step NO + N2O5 3NO2 fast step What is the rate law predicted by this mechanism? a. Rate = k1[N2O5] b. Rate = k2[NO2][NO3] c. Rate = k3[NO][N2O5] d. Rate = k1k2k3[N2O5]2
Rate = k1[N2O5]
What can be stated about the two potential energy diagrams shown below with respect to their relative rates of reaction and heat exchange? a. Reaction 1 proceeds faster than reaction 2. Both reactions are exothermic. b. Reaction 2 proceeds faster than reaction 1. Reaction 1 is endothermic and reaction 2 is exothermic. c. Reaction 1 proceeds faster than reaction 2. Reaction 1 is exothermic and reaction 2 is endothermic. d. Reaction 1 proceeds faster than reaction 2. Reaction 1 is endothermic and reaction 2 is exothermic.
Reaction 2 proceeds faster than reaction 1. Reaction 1 is endothermic and reaction 2 is exothermic
A titration run is performed with 0.15 M Solution A in a beaker and 0.15 M Solution B added from a buret as shown in the right panel of the figure below. A titration curve is plotted wherein the pH of the solution in the beaker is plotted as a function of the volume of Solution B added from the buret. Based on the titration curve, which of the following statements is true. a. Solution A is a strong base and Solution B is a strong acid. b. Solution A is a weak base and Solution B is a weak acid. c. Solution A is a strong base and Solution B is a weak acid. d. Solution A is a strong acid and Solution B is a weak base.
Solution A is a strong base and Solution B is a weak acid
What will happen if 0.1 mol of solid silver(I) nitrate is added to 1.0 L of a saturated solution of silver(I) chromate? For Ag2CrO4, Ksp = 2.4 × 10-12. a. The AgNO3 will settle to the bottom without dissolving. b. Some Ag2CrO4 will precipitate. c. Nothing will happen. d. The concentration of CrO42- will increase.
Some Ag2CrO4 will precipitate.
Which of the following salts has the highest molar solubility in water? a. SrCO3 (Ksp = 9.3 × 10-10) b. BaSO4 (Ksp = 1.1 × 10-10) c. BaCrO4 (Ksp = 1.2 × 10-10) d. PbS (Ksp = 2.5 × 10-27)
SrCO3 (Ksp = 9.3 × 10-10)
The elementary steps for a catalyzed reaction are shown below. Identify the catalyst? Identify the intermediate? H2O2(aq.) + I−(aq.) → H2O(l) + IO−(aq.) IO−(aq.) + H2O2(aq.) → H2O(l) + O2(g) + I−(aq.) a. The catalyst is IO−(aq.); the intermediate is I−(aq.). b. The catalyst is H2O(l); the intermediate is I−(aq.). c. The catalyst is I−(aq.); the intermediate is H2O2(aq.). d. The catalyst is I−(aq.); the intermediate is IO−(aq.).
The catalyst is I−(aq.); the intermediate is IO−(aq.)
The third law of thermodynamics states: a. The entropy is zero at 0 K for a perfect crystal. b. The absolute entropy of a substance decreases with increasing temperature. c. The entropy of the universe is increasing. d. The entropy of the universe is constant.
The entropy is zero at 0 K for a perfect crystal
The second law of thermodynamics states that: a. The entropy of the universe is constant. b. The entropy of the universe is increasing. c. The entropy of a perfect crystal is zero at 0 K. d. The energy of the universe is constant.
The entropy of the universe is increasing
For a particular chemical reaction ΔH = 7.6 kJ and ΔS = -15 J/K. Under what temperature condition is the reaction spontaneous? a. The reaction is spontaneous at all temperatures. b. When T < 507 K. c. When T > 507 K. d. The reaction is not spontaneous at any temperature.
The reaction is not spontaneous at any temperature.
Which of the following is always true for a reaction where K is 2.75 × 108 at 25°C? a. The reaction mixture contains mostly products at equilibrium. b. The reaction mixture contains mostly reactants at equilibrium. c. The reaction is very slow. d. There are approximately equal moles of reactants and products at equilibrium.
The reaction mixture contains mostly products at equilibrium
Which of the following is a correct statement of Henry's law? a. The solubility of a gas in solution is inversely proportional to temperature. b. The solubility of a gas in solution is directly proportional to pressure. c. The solubility of a gas in solution is independent of pressure. d. The solubility of a gas in a solution is inversely proportional to pressure.
The solubility of a gas in solution is directly proportional to pressure.
The reaction quotient Q for a system is 3.9 × 103. If the equilibrium constant K for the same system is 2.0 × 10-4, what will happen as the reaction mixture approaches equilibrium at the same temperature? a. There will be a net loss in product(s), i.e., the reaction shifts to the right until equilibrium is reached. b. There will be a net loss in both product(s) and reactant(s). c. The equilibrium constant will increase until it equals the reaction quotient. d. There will be a net loss in reactant(s), i.e., the reaction shifts to the left until equilibrium is reached.
There will be a net loss in reactant(s), i.e., the reaction shifts to the left until equilibrium is reached.
Which of the following is the strongest acid? a. V4- b. V c. V4+ d. V2-
V4+
A cucumber is placed in a concentrated salt solution. What is most likely to happen? a. Water will flow from the solution to the cucumber. b. Salt will precipitate out. c. No change will occur. d. Water will flow from the cucumber to the solution.
Water will flow from the cucumber to the solution
According to the following cell notation, which species is undergoing oxidation? Zn | Zn2+(aq) || Mn2+(aq) | MnO2(s) | Pt(s) a. MnO2(s) b. Zn2+(aq) c. Mn2+(aq) d. Zn(s)
Zn(s)
The solubility of AgCl in water is __________ the solubility of AgCl in strong acid at the same temperature. a. Additional information is needed. b. less than c. about the same as d. greater than
about the same as
In a voltaic cell, electrons flow from the _____ to the _____ through the _____. a. cathode, anode, wire b. anode, cathode, wire c. anode, cathode, salt bridge d. cathode, salt bridge, wire
anode, cathode, wire
The following equilibrium is exothermic. How could the yield of diiodine pentoxide be increased? I2(g) + 5CO2(g) ⇌ 5CO(g) + I2O5(g) a. by decreasing the pressure b. by decreasing the temperature c. by decreasing the volume of the reaction vessel d. by increasing the pressure
by decreasing the temperature
Which of the following changes represent a decrease in entropy? a. decomposition of fallen leaves b. melting snow c. condensation of steam on glass d. evaporation of gasoline
condensation of steam on glass
The pH at the equivalence point of a titration of a weak acid with a strong base will be a. greater than 7.00. b. More data is needed to answer this question. c. less than 7.00. d. equal to 7.00
greater than 7.00
Which of the following would be the best solvent for removal of trace amounts of water from a surface? a. hexane, CH3CH2CH2CH2CH2CH3 b. methanol, CH3OH c. diethyl ether, CH3CH2OCH2CH3 d. hydrogen telluride, H2Te
methanol, CH3OH
ΔSsurr is _______ for endothermic reactions and ______ for exothermic reactions. a. negative, negative b. negative, positive c. positive, positive d. positive, negative
negative, positive
Which of the following is the correct definition for an Arrhenius base? a. electron pair acceptor b. proton donor c. provides OH− in water d. proton acceptor
provides OH− in water
Which of the following solutions would have the highest freezing point? a. 0.15 m Zn(CH3COO)2 b. 0.16 m BaI2 c. pure water d. 0.10 m Cr2(SO4)3
pure water
An unknown acid is titrated with an NaOH solution of equal concentration, yielding the titration curve on the right. Based on this curve, which of the following could be the unknown acid? a. hydrazoic acid (HN3; Ka = 2.51 × 10-5) b. phenol (C6H5OH); Ka = 1.02 × 10-10) c. pyruvic acid (CH3COCOOH; Ka = 4.07 × 10-3) d. chromic acid (H2CrO4; Ka1 = 1.82 × 10-1, Ka2 = 3.24 × 10-7)
pyruvic acid (CH3COCOOH; Ka = 4.07 × 10-3)
The reaction 2A + 5B → products is first order in A and first order in B. What is the rate law for this reaction? a. rate = k[A][B]2 b. rate = k[A]5[B]2 c. rate = k[A][B] d. rate = k[A]2[B]5
rate = k[A][B]
In the presence of fulvic and humic acids (organic macromolecules derived from the biological decay of dead plants and animals), Ag+ and Au3+ ions in natural aqueous media form metallic Ag and Au nanoparticles respectively. Under certain conditions, these ions can also form Ag—Au bimetallic alloy nanoparticles (Alivio, T. E. G., et al. Environmental Science & Technology. 2018, 52, 7269-7278). The environmental toxicity of the Ag—Au alloy nanoparticles is a function of the amount of Ag incorporated. What is the role of fulvic and humic acids in the conversion of Ag+ to Ag and Au3+ to Au, and ultimately, the formation of Ag-Au alloys? a. oxidizing agent b. reducing agent c. strong acid d. ligand
reducing agent
If a reaction is zero-order in a reactant, when the concentration of the reactant is decreased by a factor of 2, the reaction rate will a. remain constant b. decrease by a factor of 1/2. c. quadruple. d. decrease by a factor of 1/4.
remain constant
An activated complex (transition state) is __________. a. a stable molecule that is formed during an early step of a reaction, and consumed in a later step b. the arrangement of atoms at the top of the potential energy barrier c. a substance that acts to increase the rate of a reaction without itself being consumed d. a substance that forms during a reaction that has a definite, well-known structure
the arrangement of atoms at the top of the potential energy barrier
The main reason for the increase in reaction rate with temperature is that a. a 10°C temperature rise results in the rate doubling. b. the fraction of high-energy molecules increases exponentially with temperature. c. there is a dramatic decrease in the number of collisions. d. the activation energy increases rapidly with temperature.
the fraction of high-energy molecules increases exponentially with temperature
Equilibrium is reached in chemical reactions when a. the concentrations of reactants and products become equal. b. the rates of the forward and reverse reactions become equal. c. the temperature shows a sharp rise. d. all chemical reactions stop.
the rates of the forward and reverse reactions become equal.
The anode in a voltaic cell and in an electrolytic cell is a. the site of reduction in both cells. b. the site of oxidation and of reduction, respectively. c. the site of reduction and of oxidation, respectively. d. the site of oxidation in both cells.
the site of oxidation in both cells.
A non-spontaneous electrochemical reaction has: a. ΔG° = 0, E° = 0, K > 1 b. ΔG° > 0, E° < 0, K < 1 c. ΔG° < 0, E° > 0, K > 1 d. ΔG° > 0, E° < 0, K > 1
ΔG° > 0, E° < 0, K < 1
Which of the following statements is always true for a spontaneous process? a. ΔSsys > 0 b. ΔSuniv > 0 c. ΔGsys > 0 d. ΔSsurr > 0
ΔSuniv > 0
