Chemistry Reference
In-Depth Information
The concentration of B in its solution must be very low because the concen-
tration of A cannot be much greater than
10
1
,
at most.
10
5
.
Practice Problem 11.13
The ratio of molarities of A to B is
What can be deduced from this fact?
Snapshot Review
❒
Molarity, the number of moles of solute per liter of solution, can be
used as a factor to find the volume of a solution from the number of
moles of solute or vice versa.
ChemSkill Builder 6.1
❒
Molarity may also be defined as the number of millimoles per
milliliter of solution (but not the number of moles per milliliter of
solution or the number of millimoles per liter of solution).
❒
If two or more substances are dissolved in the same solution, they
may react or not. The numbers of moles of each solute in the final
solution will be different in these two cases.
A. Calculate the concentration of a solution containing
(a) 0.125 mol of solute in 0.375 L of solution.
(b) 125 mmol of solute in 375 mL of solution.
(c) 0.125 mol of solute in 375 mL of solution.
B. Calculate the number of millimoles of solute in 15.0 mL of 2.00 M solute.
C. Calculate the concentration of a solution prepared by adding 75.0 mmol
of
CH
3
OH
in 25.0 mL of aqueous solution to 45.0 mmol of
CH
3
OH
in
25.0 mL and diluting to 200.0 mL.
11.2
Molarities of Ions
As shown in Section 11.1, the molarities of ionic compounds can be calculated
just as the molarities of covalent compounds are. The molarity of an ionic com-
pound is the number of moles of the
compound
per liter of solution. However,
as discussed in Chapter 9, it is often useful to describe ionic compounds in solu-
tion as the separate ions. The molarity of any ion is simply the number of moles
of
that ion
per liter of solution.
EXAMPLE 11.14
(a)
Calculate the molarity of if 0.220 mol of that compound is
dissolved in enough water to make 0.500 L of solution.
AlCl
3
(b)
Calculate the concentration of each type of ion in that solution.
Solution
0.220 mol AlCl
3
0.500 L
(a)
0.440 M AlCl
3
