Chapter 15 – Solutions
-homogenous mixture (uniform mixing of
components)
Solvent – ? Substance in the majority
Solute - ?
Substance in the minority
Process of an ionic solute dissolving in water:
Show a dissociation equation for:
FeCl2
FeCl3
Na3PO4
Process of alcohol, a molecular substance, dissolving in water
Sugar dissolved in water:
Animation
Hydrocarbon in water:
Ways to express concentration of a solution:
Qualitative:
Saturated – no more solute will dissolve.
Unsaturated – more solute will dissolve
Supersaturated – too much solute is dissolved.
Unstable!
Concentrated
Dilute
Quantitative:
I. Mass Percent =
mass solute x 100
mass solution
Problem: 1.0 gram of salt is added to 48 grams water. Determine
mass percent of salt.
What is the mass percent of water?
Problem: 22.0 grams ethanol are added to 64.0 grams water. Determine the
mass percent of ethanol.
Problem: Cow milk has a sugar in it called lactose, and is 4.5% by mass
lactose. Calculate the grams of lactose in 175 grams of milk.
II.
Molarity =
moles solute
Liters of solution
=
M
Problem: What does 3 M HCl mean?
Problem: Calculate the molarity of a solution containing 11.5 grams NaOH
plus enough water to make 1.50 liters solution.
Problem: Describe how to make 2.50 L of 1.20 M sodium chloride solution.
Problem: Calculate the concentration of each ion in a solution of
a) .50 M Co(NO3)2
b) 0.75 M FeCl3
Problem: What is the molarity of the Cl- in 25 mL of 0.75 M CaCl2 solution?
How many moles of Cl- are in this solution?
Dilution of concentrated solution M1V1 = M2V2
Problem: You have 12 M concentrated HCl, and want to make 5.0 L of
1.0 M HCl. Describe how to do this.
“What you
otter
(ought to do)
is add acid to water!”
Problem: Describe how to make 1.5 L of .10 M H2SO4 from 18.3 M
concentrated H2SO4.
Solution Stoichiometry
Problem: Calculate the mass of NaCl needed to react with 1.50 Liters of
0.100 M AgNO3.
Determine the mass of AgCl that will form.
Problem: Calculate the mass of BaCrO4 formed when 0.00350 moles of
Ba(NO3)2 reacts with 265 mL 0.0100 M K2CrO4
Problem: Calculate the liters of 12 M HCl needed to dissolve
a 1.0 ton iron vehicle
Neutralization of acids and bases:
Problem: What volume of 0.25M H2SO4 is required to neutralize 175
mL of 0.40 M NaOH?
Problem: Calculate the volume of 0.15 M KOH needed to neutralize 1.00 Liters
of 2.5M H3PO4.
III. Normality (N) - a measure of H+ and OH- in a solution of acid or base.
What is the molarity of the H+ in 2 M HCl? 2 M H2SO4?
HCl H+ + ClH2SO4 2H+ + SO4-2
N = M x #H+ in acid formula
N = M x # OH- in base formula
Problem:
Determine the Normality of:
2 M HCl
1.5 M H2SO4
2.5 M H3PO4
1.5 M NaOH
0.00020 M Ca(OH)2
Problem: Calculate the number of grams HNO3 needed to make 125 mL of
0.150 N HNO3.
Problem: How many grams of phosphoric acid are needed to make
250. mL 0.030 N H3PO4.