8th Grade Chemical Interactions
Solutions Concepts
1. Mixture is defined as a combination of two or more substances. Mixtures
can be solid, liquid, or a gas.
2. Solute is the substance that dissolves (i.e. the salt) and the solvent is the
substance in which the solute dissolves (i.e. the water).
3. When two substances are mixed, and it looks like the one disappears in
the other, the substances form a solution and the process is called
dissolving.
4. A solution is a mixture of two (or more) substances. In a solution, one
substance, the solute, is dissolved into the other substance, the solvent.
5. When a solute dissolves, it is broken into particles by solvent particles.
The solute particles are carried into the solvent by solvent particles. The
solute particles are distributed uniformly throughout the particles of the
solvent.
6. Dissolving involves both kinetic interactions (collisions) and attractive
forces (bonds).
7. There is a limit to the amount of solute that can dissolve in a given
amount of solvent. When the solvent has no more room for solute
particles, the solution is saturated. When you dissolve a solid substance
in water until no more will dissolve, the solution is a saturated solution.
Additional solute will remain un-dissolved on the bottom of the
container.
8. When a solution is saturated at the particle level, the available space
between the water particles was filled by the solute (i.e. sodium chloride
particles). There was no more space between the water particles (solvent)
for additional solute (i.e. sodium chloride) particles. No more solute (i.e.
salt) could dissolve. The solution is then said to be saturated.
8th Grade Chemical Interactions
9. The amount of solute dissolved in a volume of solvent determines the
concentration of the solution. Concentration is a ratio of solute to
solvent in a solution. The solution with more solute is more concentrated.
10. The substances in a solution are not changed chemically when they
dissolve. Often, evaporation will separate the solvent and the solute.
11.When equal volumes of solutions made with the same substance are
weighed, the sample with the greatest mass is most concentrated.
Conversely, the sample with the lowest mass is the least concentrated.
There is a direct relationship between mass and concentration.
Mid-Summative Exam 8 Review Concepts
 Be able to draw the amount of concentration in a solution.
 How would you make a saturated solution? How would you know
that it is saturated?
 Be able to determine the volume of water given the solute and
mass of a solution and explain how you arrived at the answer in a
complete sentence.
 Be able to explain how adding a solute to a solution will affect the
mass of a solution.
 When do two items have the same concentration?
 Be able to describe the dissolving process.
 Identify who has the most concentration and why.