Solutions (Homogeneous mixtures)
- Solutions are composed of one or many solute(s) and only 1 solvent
Solute : - the smaller quantity of the solution
- substance that dissolves into the solvent
Solvent : - the larger quantity of the solution
- substance that dissolves the solute(s)
- A solution can exist in any of the 3 states of matter:
(solid, liquid or gas)
Solid Solutions ex : brass = copper + zinc This is called
(solvent) (solute) an alloy.
Gas Solutions ex : air = nitrogen + oxygen + argon + carbon dioxide
(solvent) (all solutes)
Liquid Solutions ex : vinegar = acetic acid + water
(solute) (solvent)
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Dissolution
- When 2 or more substances mix to form a solution, dissolution occurs. The solute (salt) dissolves in the solvent (water).
How does this happen?
1) The particles of a solute (salt) are more attracted to the particles of a solvent (water) than they are to themselves.
2) The solvent (water) particles detach the solute
(salt) particles from the grain and keep it away from other solute (salt) particles.
3) When dissolution is complete the solute particles
(salt) will be uniformly distributed in the solvent particles (water).
- if the particles of the solute are not attracted to the particles of the solvent, the two substances cannot form a solution  this will result in a heterogeneous mixture (ex: sand and water)
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Solutions Vocabulary concentration: it is a ratio (proportion) the amount of solute (ex: salt) which is dissolved in a given quantity of solvent (ex: water) dilute solution: a solution with a low concentration . ie. a low amount of solute in relation to the solvent concentrated solution: a solution with a high concentration. ie. a high amount of solute in relation to the solvent unsaturated solution: a solution that still contains room for more solute particles to dissolve into the solvent particles saturated solution: a solution in which all the spaces between solvent (water) particles have been filled by solute (salt); it can hold no more solute solubility: the maximum amount of solute that can be dissolved in a given quantity of solvent (at this point the solution is said to be saturated)
*** solubility is a characteristic property ***
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Solutions and Mixtures Practice Questions
1) A solution is defined as a mixture that is... a) Homologous b)
Heterogeneous c)
Homogeneous
2) Which of these is a solution? a) 14K Gold b) Salt Water c) Carbonated Water d) All of the Above
3) Solutions with low concentrations of solutes are... a) Concentrated b) Dilute c) Solvents d) None of the Above
4) The most common solvent of Earth is... a) Gasoline b) Water c) Turpentine d) None of the Above
5) All liquids are able to be mixed to create solutions. a) True b) False
6) Mixtures are always combinations of the same compounds that are in different states. a) True b)
False
7) All mixtures are defined as "heterogeneous." a) True b) False
8) All solutions are mixtures, but not all mixtures are solutions. a) True b) False
9) Which of these is not a mixture? a) Solution b) Alloy c) They are all mixtures.
10) Which of these is not a mixture? a) Oil and Water b) Sand and Water c) Diet Soda d) All are mixtures.
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Homework (to be completed for next class):
Part 1
1) Fill one glass with one cup of water.
2) Add one teaspoon (normal small spoon) of salt to the glass.
Stir.
3) Observe the solution.
4) Continue to add one teaspoon of salt at a time to the glass until you notice that the solution has become supersaturated (you will be able to tell because the salt will no longer dissolve in the water and will fall to the bottom of the glass).
5) Record how many teaspoons of salt it took until the solution became supersaturated.
Part 2:
1) Repeat the same procedure but this time do it with sugar.
2) Record how many teaspoons of sugar it takes until the solution becomes supersaturated.
Answer the following questions in your logbook:
1) How many teaspoons of salt did it take for the solution to become supersaturated?
2) How many teaspoons of sugar did it take for the solution to become supersaturated?
3) What does this tell you about the solubility of salt versus the solubility of sugar in water?
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