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    Practice problems in chemistry - 10 problems

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    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

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    please see the attachment

    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 [Correct, Ksp = [Product+][Product-], lowest Ksp means this product is lowest]

    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 : [Wrong, Ksp = [Product+][Product-], lowest Ksp means this product is low]

    For a reaction AB <=> nA+ + mB-, Ksp = [A+]^n *[B-]^m, n and m are integers. If [A+] and [B-] are very low, Ksp will also be very low. (Same reasoning was applied to the first question) Correct answer is A

    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 ...

    Solution Summary

    The solution provides and easy to follow explanation of the concepts and gives all mathematical steps wherever necessary.

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