Solutions
Properties of Water
Solutions
Predict the % water in the following
foods
Predict the % water in the following
foods
88% water
94% water
85% water
86% water
Water in the Body
water gain
liquids
1000 mL
food
1200 mL
cells
300 mL
water loss
urine
1500 mL
perspiring 300 mL
exhaling
600 mL
feces
100 mL
Calculate the total water gain and water loss
Total ______ mL
_____ mL
Water
 Most common solvent
 A polar molecule
O a hydrogen bond
H +
H +
Hydrogen Bonds Attract Polar
Water Molecules
Explore:
Surface Tension
 Fill a glass to the brim with water
 How many pennies can you add to the
glass without causing any water to run
over?
Predict _________________
Actual _________________
 Explain your results
Explore
1. Place some water on a waxy surface. Why
do drops form?
2. Carefully place a needle on the surface of
water. Why does it float? What happens if
you push it through the water surface?
3. Sprinkle pepper on water. What does it
do? Add a drop of soap. What happens?
Surface Tension
 Water molecules within water hydrogen
bond in all directions
 Water molecules at surface cannot hydrogen
bond above the surface, pulled inward
 Water surface behaves like a thin, elastic
membrane or “skin”
 Surfactants (detergents) undo hydrogen
bonding
Solute and Solvent
Solutions are homogeneous mixtures of
two or more substances
Solute
The substance in the lesser amount
Solvent
The substance in the greater amount
Nature of Solutes in Solutions
 Spread evenly throughout the solution
 Cannot be separated by filtration
 Can be separated by evaporation
 Not visible, solution appears transparent
 May give a color to the solution
Types of Solutions
air
O2 gas and N2 gas
gas/gas
gaseosa
CO2 gas in water
gas/liquid
seawater
NaCl in water
solid/liquid
brass
copper and zinc
solid/solid
Discussion
Give examples of some solutions
and explain why they are solutions.
Test yourself
(1) element
(2) compound
(3) solution
A. water
1
2
3
B. sugar
1
2
3
C. salt water
1
2
3
D. air
1
2
3
E. tea
1
2
3
Answers
(1) element
(2) compound
A. water
2
B. sugar
2
C. salt water
3
D. air
3
E. tea
3
(3) solution
Test yourself
Identify the solute and the solvent.
A. brass: 20 g zinc + 50 g copper
solute
=
1) zinc
2) copper
solvent
=
1) zinc
2) copper
B. 100 g H2O + 5 g KCl
solute
=
1) KCl
2) H2O
solvent
=
1) KCl
2) H2O
Answers
A. brass: 20 g zinc + 50 g copper
solute
solvent
=
=
1) zinc
2) copper
B. 100 g H2O + 5 g KCl
solute
=
1) KCl
solvent
=
2) H2O
Test yourself
Identify the solute in each of the following
solutions:
A. 2 g sugar (1) + 100 mL water (2)
B. 60.0 mL ethyl alcohol(1) and 30.0 mL
of methyl alcohol (2)
C. 55.0 mL water (1) and 1.50 g NaCl (2)
D. Air: 200 mL O2 (1) + 800 mL N2 (2)
Answer
Identify the solute in each of the following
solutions:
A. 2 g sugar (1)
B. 30.0 mL of methyl alcohol (2)
C. 50 g NaCl (2)
D. 200 mL O2 (1)
Like dissolves like
A ____________ solvent such as water is
needed to dissolve polar solutes such as
sugar and ionic solutes such as NaCl.
A ___________solvent such as hexane
(C6H14) is needed to dissolve non-polar
solutes such as oil or grease.
Self test
Which of the following solutes will
dissolve in water? Why?
1) Na2SO4
2) gasoline
3) I2
4) HCl
Answer
Which of the following solutes will
dissolve in water? Why?
1) Na2SO4
Yes, polar (ionic)
2) gasoline
No, non-polar
3) I2
No, nonpolar
4) HCl
Yes, Polar
Formation of a Solution
H2O
Cl- Na+
Na+ Clsolute
Na+
H2O Cl-
Hydration
Dissolved
solute
Writing An Equation for a
Solution
When NaCl(s) dissolves in water, the
reaction can be written as
H 2O
NaCl(s)
solid
Na+ (aq) + Cl- (aq)
separation of ions in water
Self test
Solid LiCl is added to some water. It
dissolves because
A. The Li+ ions are attracted to the
1) oxygen atom(-) of water
2) hydrogen atom(+) of water
B. The Cl- ions are attracted to the
1) oxygen atom(-) of water
2) hydrogen atom(+) of water
Answer
Solid LiCl is added to some water. It
dissolves because
A. The Li+ ions are attracted to the
1) oxygen atom(-) of water
B. The Cl- ions are attracted to the
2) hydrogen atom(+) of water
Rate of Solution
You are making a chicken stock using an
oxo cube. What are some things you can
do to make it dissolve faster?

Crush it

Use hot water (increase temperature)

Stir it
Self test
You need to dissolve some gelatin in
water. Indicate the effect of each of the
following on the rate at which the gelatin
dissolves as (1) increase, (2) decrease,
(3) no change
A. ___Heating the water
B. ___Using large pieces of gelatin
C. ___Stirring the solution
Answer
You need to dissolve some gelatin in
water. Indicate the effect of each of the
following on the rate at which the gelatin
dissolves as (1) increase, (2) decrease,
(3) no change
A. 1 Heating the water
B. 2 Using large pieces of gelatin
C. 2 Stirring the solution