•A solution is the same thing as a homogeneous mixture (a mixture with the exact same composition throughout).
Parts of a Solution•Solute-the substance that is being dissolved in a solution
•Solvent-the substance in a solution that is doing the dissolving
Parts of a Solution•Example:
– In a saltwater solution (salt dissolved in water):
–Salt is the solute–Water is the solvent
•When two liquids are able to dissolve into each other, they are called miscible.ex) water & vinegar
•If not, they are called immiscible.ex) water & oil
•Solubility is the amount of a substance that will dissolve into an amount of solvent at a given temperature
•A solvent (like water, for example) can only hold so much of a solute.
•Or in other words, there is a maximum amount of solute that any solvent can hold.
•Concentration-the amount of solute that is dissolved into a solvent
•Concentrated-when a solution has a high concentration of solute
•Dilute-when a solution has a low concentration of solute
•Concentration can be described in terms of “weak” or “strong”, “concentrated” or “dilute”, but these are both relative terms and can be subjective.
•A more objective way to describe concentration is molarity; we will discuss molarity in more detail later this year.
•A saturated solution cannot hold any more of a solute at a given temperature.
•An unsaturated solution can hold more solute at a given temperature.
•Sometimes, a solution can hold more of a solute than it should theoretically hold. This type of solution is called supersaturated.
•A supersaturated solution requires heating and stirring.
Summary: Types of Solutions:
Unsaturated Saturated Super Saturated
Solvent can not hold more solute;
‘full’
Solvent can hold more solute; not
‘full’
Solvent holds more solute than normal;
‘extra full’
‘Soup Can’ analogy: Think of the solvent as a can, and the solute as the soup.Unsaturated Saturated Super Saturated
•In gases, pressure affects solubility. The higher the pressure, the more gas is soluble in a solvent.
•ex) carbonated drinks
•Generally, a substance’s solubility increases as temperature is increased.
•Why? •The solvent’s particles are moving faster and can dissolve more solute.
•In gases, however, as the temperature increases, the solubility of the gas decreases.
•ex) power plants can kill fish because of the increased temperature of the water and reduced levels of oxygen
Practice Problem #3• How many grams
of NaNO3 can 75 grams of water hold at 55 oC?
• 105 grams of NaNO3 in 100 grams of water:– 105 g/100 g = x /75 g– X = (105x75)/100– X = 78.75 g NaNO3
Practice Problem #4
• What type of solution results when you mix 45 g of NH4Cl in 100 g of water at 70 oC?
• Can hold 63 g; 45 g < 63 g; solution is unsaturated.
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