5 Steps to a 5 AP Chemistry 2019

AP Chemistry Practice Exam 1 ❮ 329

❯ AP Chemistry Practice Exam 1, Section II (Free Response)

Time—1 hour and 45 minutes

Answer the following questions in the time allowed. You may use a calculator and the resources at the back

of the book. Write the answers on separate sheets of paper.

Compound Ksp

AgIO 3 3.0 × 10 –8

Ba(IO 3 ) 2 1.5 × 10 –9

Cu(IO 3 ) 2 7.4 × 10 –8

La(IO 3 ) 3 6.2 × 10 –12

Ni(IO 3 ) 2 1.4 × l0–8

Zn(IO 3 ) 2 2.0 × l0–8

Question 1

Use the Ksp data given above to answer the following questions.

A chemist is investing the chemistry of metal iodate compounds. Some of her data are in the Ksp table given

above. In addition to this information, she knows that sodium iodate, NaIO 3 , is soluble in water and that

iodic acid, HIO 3 , has Ka = 0.16 at 25°C.

(a) (i) Write a balanced chemical equation for the dissolution equilibrium of nickel(II) iodate, Ni(IO 3 ) 2 ,

in water.

(ii) Write the Ksp relationship for the dissolution equilibrium of nickel(II) iodate.

(iii) What is the concentration of iodate ions in a saturated solution of nickel(II) iodate?

(b) What is the solubility of copper(II) iodate, Cu(IO 3 ) 2 , in a 0.10 M copper(II) nitrate, Cu(NO 3 ) 2 ,

solution?

(c) (i) How does the solubility of silver iodate, AgIO 3 , in 1.0 M nitric acid compare to its solubility in

pure water?

(ii) Explain your answer to part c(i).

(d) Which of the following will produce a higher iodate ion concentration in solution, barium iodate,

Ba(IO 3 ) 2 , or lanthanum iodate, La(IO 3 ) 3? What is the iodate ion concentration for each of these two

compounds?

(e) Write a balanced net ionic equation for the addition of a sodium iodate solution to a zinc nitrate,

Zn(NO 3 ) 2 solution. Recall that sodium nitrate, NaNO 3 , is very soluble in water.

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