A
mixture is 2 or more substances that are
combined together that can be separated by
physical means (not chemically bonded
together)
 Heterogeneous
mixtures – unevenly mixed
mixtures, “different” composition throughout
 Homogeneous
mixtures– evenly mixed mixtures,
“same” composition throughout
 Which

type of mixture are solutions?
Homogenous mixtures
 Solutions
have the same composition,
color, and density throughout them
 We call solutions the “best mixed
mixtures”
 If a solution is made from a substance
dissolved in water, it is called an aqueous
solution

To create a solution, one substance must dissolve
in another substance

Solute – the substance being dissolved
 When solids or gases are dissolved in
liquids, they are considered to be the
solutes

Solvent – the substance that does the dissolving
 When a liquid dissolves another liquid, the
liquid that has the largest amount is
considered to be the solvent
As a general rule of thumb, there is LESS solute
and MORE solvent in a solution

Solutions do not always involve a solid or gas
dissolving in a liquid

Solid dissolved in solid


Gas dissolved in gas


i.e. air (78% nitrogen, 21% oxygen, 1% other gases)
Liquids dissolved in gas


i.e. Alloys - brass (Melted metal solute mixed with melted
metal solvent and cooled)
i.e. clouds
Gas dissolved in solid

i.e. marshmallows

For each example, identify the solute and the solvent:

Kool-Aid



Sterling Silver (92.5% silver, 7.5% copper)



copper
Solute: _____________________
silver
Solvent: _____________________
Styrofoam



sugar/ Kool-Aid powder
Solute: _____________________
water
Solvent: _____________________
air (gas)
Solute: _____________________
foam (solid)
Solvent: _____________________
Mountain Dew


sugar, carbon dioxide (gas)
Solute: _____________________
Solvent: _____________________
water

1. Moving solvent molecules cluster
around the solute

They are attracted to each other
because they have opposite charges
(like a magnet)

2. The solvent molecules pull the
solute molecules into the solution

3. The solvent and solute molecules
spread out to form a homogeneous
mixture

Dissolving Animation
 What
can you do to increase the rate at
which solutes dissolve in solvents?

Stir it!


Decrease crystal size


By stirring, you are bringing more solvent in contact
with the solutes, which cause the particles to dissolve
more quickly
If you make larger solutes smaller, you are increasing
the surface area of the crystals which allows the
solvent to surround it more easily
Increase temperature

Increasing the temperature speeds up the movement
of the particles which causes more of the solvent
particles to bump into the solute particles
Review Song:
http://www.youtube.com/w
atch?v=3G472AA3SEs