Ionics

1) Why is it not very accurate to describe an aqueous metal ion as M+(aq)? Choose from:

-because the metal ion is actually bound to several water molecules in a complex ion
-because formation constants of complex ions tend to be very large, which makes the aqueous ions difficult to generate in solution
-because a metal ion, M+, is actually a Lewis acid, which is not reflected in the notation
-because the notation ignores what else is present around the ion

2) Lead thiocyanate, Pb(SCN) 2 , has a K sp value of 2.00×10 −5 .Calculate the molar solubility of lead thiocyanate in 0.600M KSCN . Express your answer with the appropriate units.

3) Calculate the pH of the solution made by adding 0.50mol of HOBr and 0.30 mol of KOBr to 1.00 L of water. The value of K a for HOBr is 2.0×10 −9 .Express your answer numerically using two decimal places.

4) Buffer capacity depends on two quantities. What are they? Choose from:

-an equal number of conjugate acid and base molecules, and a high concentration of each
-how close the buffer is to having a 10:1 ratio of the buffer components, and having a high concentration of the components
-a high concentration of conjugate acid molecules in solution and the pH of the solution
-the range of pH values over which the solution can act as a buffer, and an equal ratio of conjugate acid to conjugate base

5) Calculate the ratio of CH 3 NH 2 to CH 3 NH 3 Cl required to create a buffer with pH = 10.14. Express your answer using two significant figures.