Grade 7 Science
Unit 3: Mixtures and
Solutions
Chapter 8: Some substances dissolve to form
solutions faster and more easily than others.
Name: __________________________
Section: ____________
Making Solutions
When you mix two substances they form a ____________________
Solutions have two parts
The substance that
dissolves
(found in less
amounts)
ex: sugar
The substance in
which the solute
dissolves.
(found in the
greatest amount)
Ex :water
For each situation identify the solute and the solvent:
Situation
A. Brass is used to
make many
objects. Brass is a
solution of zinc
metal in a copper
metal
B. Hydrogen
peroxide is used to
disinfect cuts.
Hydrogen
peroxide is a
solution of 3%
hydrogen and 97%
water.
C. Dental amalgam is
a metal that is
used to fill
cavities. It is a
solution of
mercury in tin.
D. Deicing fluid is a
cleaner used to
clean car and truck
windshields. It is
made up of a
solution of
propylene glycol
in water.
Solute
Solvent
Dissolving
Definition:
Dissolve
________________________________________________________________________
________________________________________________________________
If something is ABLE to dissolve then it is _________________________.
Ex: __________________________________________________________________
If something is UNABLE to dissolve then it is _______________________.
Ex: __________________________________________________________________
How are substances soluble?
According to the particle theory of matter, “there are attractive forces between the
particles”. In order to dissolve the particles must be more strongly attracted to the solvent
than to themselves. This is means the solute is soluble in the solvent.
How are substances insoluble?
If the particles of the solute are more attracted to their own particles than the solvent
particles, dissolving does not occur. The solute is said to be insoluble in that solvent.
Solvent or not??
Some materials are good solvents for some solutes but not for others. For example, Oil is
insoluble in water but soluble in gasoline.
Complete Activity 8 -1C Page 259
“Does it Dissolve?”
Different states of matter of Solutes and solvents.
Solvents and solutes can be different states of matter.
Fill in the state of matter for each solute and solvent in the given solution
Solution
Soda water
Vinegar
Salt water
Brass
Solute
Carbon dioxide
Acetic acid
salt
zinc
Solvent
water
water
water
copper
Concentration
State of solute
State of solvent
(p. 262)
The two cups below each had hot water with a tea bag sitting in them. The time
below the cup indicates how long the tea bag has been in the cup.
2 mins
______________________________
Definition:______________________
______________________________
______________________________
______________________________
10 mins
_________________________________
Definition:__________________________
____________________________
____________________________
____________________________
Directions:
1. Supposing these were clear cups, use a brown lead to color how dark you think
the tea would be in each cup.
2. Write the statement dilute solution or concentrated solution under the cup you
think it describes.
3. Write the definition for each statement in the space provided
Describing Concentration
Concentration is the amount of solute that is dissolved in a certain amount of
solvent.
Concentration can be described two ways:
“With words”
like dilute and
concentrated
“With numbers”
such as units of grams
per litre (g/L)
Question:
If you were a diabetic and had to watch you sugar intake, would you want to know the
concentration of a drink qualitatively or quantitatively? Why?
______________________________________________________________
Complete Math and Science Connect P. 272
Saturated vs. Unsaturated Solution
(Refer to p.264)
Define:
Unsaturated Solution:
________________________________________________________________________
____________________________
Saturated Solution:__________________________________________ ______
____________________________________________________
Question:
1. If there are two glasses on Kool Aid on the table, one is unsaturated the other is
saturated. How would you be able to tell the difference between the two?
________________________________________________________________________
____________________________________________________
2. It is possible to “unsaturate a saturated solution”. Suggest ways you might be
able to do this. (Hint: How could you make more sugar to dissolve in a glass of
water?)
________________________________________________________________________
____________________________________________________
______________________________________________________________
Solubility
(Refer to p. 264)
Define:
Solubility:_______________________________________________________________
_____________________________________________________
Factors that effect the Rate of dissolving
Factor
How does it affect the solubility?
A.
B.
C.
Complete activity 8-2A p. 268
“How Does Temperature Affect Solubility?”