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16 Nov 2019
Which of the following is the most effective buffer system for a pH value of 4.45? a) H3PO4/H2PO4- (Ka1 for H3PO4 is 6.9 times 10-3) b) H_2CO_3/HCO^-_3 (K_a1 for H_2CO_3 is 4.3 times 10^-7) c) HCO^-_3/CO^2-_3 (K_a2 for H_2CO_3 is 4.8 Times 10^-11) d) H_2S/HS^- (K_a1 for H_2S is 8.9 times 10^-8) e) HC_2O^-_4/C_2O^2-_4 (K_a2 for H_2C_2O_4 is 5.1 times 10^-5) What is the pH of a solution that is 0.20 M in acetic acid, HC_2H_3O_2, and 0.10 M in sodium acetate, NaC_2H_3O_2, at 25 degree C? K_a of acetic acid is 1.8 Times 10^-5. Assume the [H_3O^+] is very small compared to the 0.20 M concentration of acetic acid. a) 4.12 b) 1.53 c) 4.44 d) 2.29 e) 5.36 At 700 K, K_p (atm) for the following equilibrium is 5.6 times 10^-3. 2HgO(s) doubleheadarrow 2 Hg(l) + o_2(g) Suppose 51.2 g of mercury(II) oxide is placed a sealed 3.00-L vessel at 700 K. What is the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L middot atm/(k middot mol)) A) 0.075 atm B) 0.0056 atm C) 4.5 atm D) 19 atm E) 2.3 atm
Which of the following is the most effective buffer system for a pH value of 4.45? a) H3PO4/H2PO4- (Ka1 for H3PO4 is 6.9 times 10-3) b) H_2CO_3/HCO^-_3 (K_a1 for H_2CO_3 is 4.3 times 10^-7) c) HCO^-_3/CO^2-_3 (K_a2 for H_2CO_3 is 4.8 Times 10^-11) d) H_2S/HS^- (K_a1 for H_2S is 8.9 times 10^-8) e) HC_2O^-_4/C_2O^2-_4 (K_a2 for H_2C_2O_4 is 5.1 times 10^-5) What is the pH of a solution that is 0.20 M in acetic acid, HC_2H_3O_2, and 0.10 M in sodium acetate, NaC_2H_3O_2, at 25 degree C? K_a of acetic acid is 1.8 Times 10^-5. Assume the [H_3O^+] is very small compared to the 0.20 M concentration of acetic acid. a) 4.12 b) 1.53 c) 4.44 d) 2.29 e) 5.36 At 700 K, K_p (atm) for the following equilibrium is 5.6 times 10^-3. 2HgO(s) doubleheadarrow 2 Hg(l) + o_2(g) Suppose 51.2 g of mercury(II) oxide is placed a sealed 3.00-L vessel at 700 K. What is the partial pressure of oxygen gas at equilibrium? (R = 0.0821 L middot atm/(k middot mol)) A) 0.075 atm B) 0.0056 atm C) 4.5 atm D) 19 atm E) 2.3 atm
Sixta KovacekLv2
24 Feb 2019