Cliffs AP Chemistry, 3rd Edition

Step 4:Determine the initial concentrations of the ions that may form the precipitate in the
mixed solution.

:

..
Sr 1.
0 075
1

liter (^010) 75 10
liter
23 +-()aq ##mole= mole
:

..

0 075

1

CrO liter^005 38 10

liter

423 --()aq ##mole= mole

The total liters of solution = 0.075 + 0.075 = 0.15 liter. Therefore,

.

Sr..

liter

mole M

015

2 + ==75 10# -^3 0 050

7A

.

CrO..

liter

mole M

015

38 10 0 025

4

#^3

==

2- -

7 A

Step 5: Determine Q, the ion product.

Q=== 7 Sr^2 +A 7 CrO 4 2-A ^^0 05 0 025.. .hh1 3 10# -^3

Therefore, since Q (1.3 × 10 –3) > Ksp(7.1 × 10 –4), a precipitate will form.

Part II: Specific Topics