Chapter 14 1. For the following reaction Kc = 0.513 at 500 K. N 2 O 4 (g) 2 NO 2 (g) If a reaction vessel initially contains an N 2 O 4 concentration of 0.0500 M at 500 K, what are the equilibrium concentrations of N 2 O 4 and NO 2 at 500 K? a. [N 2 O 4 ] = 0.0770 M, [NO 2 ] = 0.0770 M b. [N 2 O 4 ] = 0.0770 M, [NO 2 ] = 0.0115 M c. [N 2 O 4 ] = 0.0115 M, [NO 2 ] = 0.0770 M d. [N 2 O 4 ] = 0.0115 M, [NO 2 ] = 0.0115 M e. [N 2 O 4 ] = 0.0117 M, [NO 2 ] = 0.0150 M *Use the following chemical reaction to answer questions 17 20.* C (s) + CO 2 (g) 2 CO (g) Kp = 1.2 x 10 3 ΔH = +256.2 kj/mol 2. If the reaction is at equilibrium and 10.0 g of C (s) is added, which of the following will occur? 3. If the reaction is at equilibrium and the volume of the container decreases by 0.05 L, which of the following will occur? 4. If the reaction is at equilibrium and heat is added, which of the following will occur?
5. If a reaction vessel contains a partial pressure of CO 2 at 0.50 atm and a partial pressure of CO at 2.5 atm, which of the following will occur? Chapter 15 6. Which of the following is an Arrhenius base? a. NH 3 b. HBrO c. HC 2 H 3 O 2 d. Mg(OH) 2 e. NaBr 7. Which of the following is a Brønsted Lowry acid? a. Al 3+ b. BF 3 c. CH 3 NH 2 d. NH 3 e. HCN 8. Which of the following is a Lewis acid? a. NH 3 b. NaBr c. Cu 2+
d. CH 3 NH 2 e. OH 9. What is the ph of a 0.00500 M solution of strontium hydroxide? a. 2.00 b. 9.24 c. 12.0 d. 13.8 10.What is the poh of a 0.0100 M solution of acetic acid? K a = 1.8 x 10 5 a. 3.37 b. 4.36 c. 6.74 d. 7.26 e. 10.63 11.What is the ph of a mixture of 100.0 ml of 0.0100 M HCl and 150.0 ml of 0.100 M HClO? K a of HClO = 2.9 x 10 8 a. 1.7 b. 2.4 c. 9.5 d. 12.3 e. 13.1 12.Which of the following salts will form a basic solution? a. LiCN b. AlCl 3 c. NH 4 Br d. NaNO 3 e. KHSO 4 13.Which of the following salts will form an acidic solution?
a. NH 4 CN NH 3 K b = 1.8 x 10 5 HCN K a = 4.9 x 10 10 b. NaHCO 3 H 2 CO 3 K a1 = 4.3 x 10 7 K a2 = 5.6 x 10 11 c. KH 2 PO 3 H 3 PO 3 K a1 =5 x 10 2 K a2 = 2.0 x 10 7 d. Li 2 SO 3 H 2 SO 3 K a1 = 1.7 x 10 2 K a2 = 6.4 x 10 8 e. CaHPO 4 H 3 PO 4 K a1 = 7.5 x 10 3 K a2 = 6.2 x 10 8 K a3 = 4.2 x 10 13 14.What is the ph of a 0.250 M solution of phosphoric acid? K a1 = 7.5 x 10 3 K a2 = 6.2 x 10 8 K a3 = 4.2 x 10 13 a. 1.36 b. 2.45 c. 5.87 d. 7.95 e. 9.16 15.What is the concentration of carbonate ions in a 0.500 M solution of carbonic acid? K a1 = 4.30 x 10 7 K a2 = 5.60 x 10 11 a. 4.64 x 10 4 b. 4.30 x 10 7 c. 2.15 x 10 7 d. 1.61 x 10 7 e. 5.60 x 10 11 16.Which of the following is the weakest acid? a. HBr b. HBrO c. HBrO 2 d. HBrO 3 e. HBrO 4 Chapter 16
17.What is the ph of the solution that results from mixing 125.0 ml of 0.10 M NH 3 with 250.0 ml of 0.10 M NH 4 Cl? K b = 1.8 x 10 5 a. 3.86 b. 8.95 c. 4.61 d. 10.82 e. 7.62 18.A 500.0 ml buffer solution is 0.125 M in HC 2 H 3 O 2 and 0.115 M in NaC 2 H 3 O 2. What is the ph of the buffer after 0.010 moles of HCl are added? Ka= 1.8 x 10 5 a. 3.86 b. 7.62 c. 4.81 d. 4.71 e. 4.56 19.Which of the following would have the best buffering capacity? a. 0.150 M HC 2 H 3 O 2 and 0.000300 M KC 2 H 3 O 2 b. 0.300 M NH 3 and 0.000250 M NH 4 Cl c. 0.500 M HClO 2 and 0.00150 M KClO 2 d. 0.550 M HClO and 0.00105 M KClO e. 0.0150 M HF and 0.0150 M NaF 20.Which of the following should be used to make a buffer with a ph of 7.20? a. HC 2 H 3 O 2 /KC 2 H 3 O 2 pk a = 4.74 b. NH 3 /NH 4 Cl pk a = 9.26 c. HClO 2 /KClO 2 pk a = 1.96 d. HClO/KClO pk a = 7.54 e. HF/NaF pk a = 3.46 21.A 35.0 ml sample of 0.175 M HBr is titrated with 0.200 M KOH. What is the volume of added base required to reach the equivalence point?
a. 30.6 ml b. 15.0 ml c. 29.2 ml d. 16.8 ml e. 28.8 ml 22.A 25.0 ml sample of 0.175 M CH 3 NH 2 is titrated with 0.150 M HBr. What is the ph after 5.0 ml of the acid is added? K b = 4.4 x 10 4 a. 7.14 b. 5.87 c. 10.64 d. 11.33 e. 11.94 Use the following titration curve to answer question 18. 23.Which of the following was used to create the titration curve shown above? a. CH 3 NH 2 titrated with HCl b. NaOH titrated with HI c. HBr titrated with KOH d. HCN titrated with Ca(OH) 2 e. HNO 3 titrated with NH 3
24.What is the molar solubility of Mg(OH) 2 in pure water? K sp = 2.06 x 10 13 a. 2.06 x 10 3 b. 3.72 x 10 5 c. 7.63 x 10 7 d. 6.70 x 10 7 e. 3.72 x 10 8 25.What is the molar solubility of barium fluoride in a 0.15 M solution of NaF? a. 0.00901 M b. 0.000150 M c. 0.00150 M d. 0.0150 M e. 0.00109 M Answer Key: 1.) C 2.) C 3.) A 4.) B 5.) B 6.) D 7.) E 8.) C 9.) C 10.) E 11.) B 12.) A 13.) C 14.) A 15.) E 16.) B 17.) B 18.) E 19.) E 20.) D 21.) A 22.) D 23.) A 24.) B 25.) E