Reference no: EM132573885

1) Which of the following pairs of substances can be used to make a buffer system?

Choose all that apply.

a) HNO₃ and KNO₃

b) H₂SO₄ and Na₂SO₄

c) NaHCO₃ and Na₂CO₃

d) H₂CO₃ and NaHCO₃

e) KCl and KCN

2) An aqueous solution has [OH^-] = 8.5 x 10^-7. What is the pH of this solution?Place your answer in the box. Express your answer using only a number or numbers without text. Report your result in decimal notation and to the proper number of significant figures. All numbers are measured.

3) In an acid-base titration, the neutralization of 20.00 mL of a solution of KOH (potassium hydroxide) of unknown concentration required the addition of 27.42 mL of 0.1042 M HNO₃ (nitric acid). Calculate the molarity of the potassium hydroxide solution.Place your answer in the box. Express your answer using only a number or numbers without text. Report your result in decimal notation and to the proper number of significant figures. All numbers are measured.

4)The pH of an aqueous solution of the salt Na₂CO₃ (sodium carbonate) will _________.

a) be basic (because it is a weak acid-strong base salt)

b) be acidic (because it is a strong acid-weak base salt)

c) be neutral (because it is a strong acid-strong base salt)

d) not be known (because it is a weak acid-weak base salt)

e) no correct response

5) If the dissociation constant of a weak acid is 8.1 x 10^-5, at what ratio should you adjust the concentration of the weak acid and its conjugate base in order to prepare a buffer that has a pH of 5.09?

a) 0.100 M weak acid with 0.100 M conjugate base

b) 0.100 M weak acid with 0.200 M conjugate base

c) 0.100 M weak acid with 0.0500 M conjugate base

d) 0.100 M weak acid with 0.0100 M conjugate base

e) 0.0100 M weak acid with 0.100 M conjugate base

6)The K_a of oxalic acid (H₂C₂O₄) is 5.37 x 10^-2. What is the pH of a buffer solution that is prepared from 0.0400 M H₂C₂O₄ and 0.0100 M sodium oxalate (Na HC₂O₄)?Place your answer in the box. Express your answer using only a number or numbers without text. Report your result in decimal notation and to the proper number of significant figures. All numbers are measured.