Practice problems in chemistry - 10 problems

Everything is already answered I just need to know if I am on the right track, please help I am really struggling with chemistry and I absolutely need to know how to do these problems correctly, so if I am wrong can you please tell me were my error is.

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Which of the following salts would give you the lowest concentration of lead ions in solution if you placed 1 mole of the salt in a liter of water?

a. PbSO4 Ksp= 1.8 x 10-8

b. PbCO3 Ksp= 1.5 x 10-13

c. PbSeO4 Ksp= 1.5 x 10-7

d. PbCrO4 Ksp= 1.8 x 10-14

Answer is D

Question 2
Which of the following salts would give you the lowest concentration of sulfate ions in solution if you placed 1 mole of the salt in a liter of water?

a. BaSO4 Ksp= 1.1 x 10-10

b. CaSO4 Ksp= 2.4 x 10-5

c. SrSO4 Ksp= 2.8 x 10-7

d. PbSO4 Ksp= 1.8 x 10-8

Answer is C

Question 3
Which of the following salts would give you the highest concentration of calcium ions in solution if you placed 1 mole of the salt in a liter of water?

a. CaCO3 Ksp= 3.8 x 10-9

b. CaCrO4 Ksp=7.1 x 10-4

c. CaSO4 Ksp= 2.4 x 10-5

d. CaHPO4 Ksp= 2.7 x 10-7

Answer is C

Question 4
Which of the following salts would give you the lowest concentration of calcium ions in solution if you placed 1 mole of the salt in a liter of water?

a. CaCO3 Ksp= 3.8 x 10-9

b. CaCrO4 Ksp=7.1 x 10-4

c. CaSO4 Ksp= 2.4 x 10-5

d. CaHPO4 Ksp= 2.7 x 10-7

Answer is A

Question 5 (10 points)
Which of the following salts would give you the highest concentration of hydroxide ions in solution if you placed 1 mole of the salt in a liter of water?

a. Fe(OH)2 Ksp= 7.9 x 10-15

b. Ca(OH)2 Ksp= 7.9 x 10-6

c. Ni(OH)2 Ksp= 2.8 x 10-16

d. Zn(OH)2 Ksp= 4.5 x 10-17

Answer is B

Question 6 (10 points)
What mass of potassium bicarbonate (KHCO3) must be added to 500 mL of a 0.200 M carbonic acid solution to make a buffer with pH = 6.30?

a. 8.73 g

b. 4.55 g

c. 24.07 g

d. 8.33 g
Answer is D

Question 7
Which of the following salts would give you the lowest concentration of hydroxide ions in solution if you placed 1 mole of the salt in a liter of water?

a. Fe(OH)2 Ksp= 7.9 x 10-15

b. Ca(OH)2 Ksp= 7.9 x 10-6

c. Ni(OH)2 Ksp= 2.8 x 10-16

d. Zn(OH)2 Ksp= 4.5 x 10-17
Answer is C

Question 8
What mass of NH4Cl must be added to 500 mL of a 0.150 M NH3 solution to make a buffer with pH = 9.50?

a. 1.14 g

b. 2.54 g

c. 6.97 g

d. 2.31 g
Answer is B

Question 9
What mass of NH4Cl must be added to 200 mL of a 0.200 M NH3 solution to make a buffer with pH = 9.30?

a. 1.95 g

b. 1.12 g

c. 2.34 g

d. 1.11 g

Answer is A

Question 10
Which of the following salts would give you the highest concentration of phosphate ions in solution if you placed 1 mole of the salt in a liter of water?

a. Ba3(PO4)2 Ksp= 1.3 x 10-29

b. Ca3(PO4)2 Ksp= 1.0 x 10-25

c. Pb3(PO4)2 Ksp= 3.0 x 10-44

d. Sr3(PO4)2 Ksp= 1.0 x 10-31

Answer is B