U2L1 Properties of Solutions

temperature increases --> solubility decreases for gaseous solutes in liquids --> warm bodies of water hold less dissolved oxygen than cold ones

Compare the amount of dissolved oxygen a warm body of water hold vs a cold body of water and explain using solubility.

1.4 g/L

The solubility of a gas is 0.58 g/L at a pressure of 104 kPa. What is its solubility if the pressure increases to 250 kPa at the same temperature?

- if a seed crystal of the solute is added --> rapid deposition on surface of the seed crystal - if the inside of the container is scratched

What are 2 ways crystallization of a supersaturated solution can occur?

above the line → supersaturated on the line → saturated below the line → unsaturated

What can a solubility graph tell you about the type of solution?

Increased temperature generally increases the solubility of solids and liquids, while decreasing solubility of gases. Increased pressure increases the solubility of gases (Henry's Law).

What condition(s) determine the solubilities of solid, liquid, and gaseous solutes in a solvent?

chemical composition of the solute and solvent

What determines whether or not a substance will dissolve?

agitation (stirring/shaking), temperature, and particle size of the solute

What factors determine how fast a substance will dissolve?

increase pressure

What would you do to change a saturated gas/liquid solution to an unsaturated solution? (increasing solubility)

add solvent

What would you do to change a saturated solid/liquid solution to an unsaturated solution?

supersaturated solution

a solution that contains more solute than it can theoretically hold at a given temperature

saturated solution

a solution that has dissolved all the solute it can at a specific temperature

Henry's Law

states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid

soluble

the ability of a substance to dissolve into another substance

solubility

the amount of solute that can be dissolved in a given quantity of a solvent at a specified temperature and pressure to produce a saturated solution

g solute per 100 g solvent

unit used to express solubility

Miscible liquids are infinitely soluble in each other, and any amount will dissolve in any given volume of each other (all proportions), while immiscible liquids are insoluble in each other.

Distinguish between miscible and immiscible liquids in terms of solubility.

Rock candy is produced from a supersaturated solution of sugar. You can make it by adding more sugar to water than will dissolve at room temperature, heating the mixture until the solubility limit has been increased enough to allow all of the sugar to dissolve, suspending a string in the hot solution, and allowing the solution to cool slowly back to room temperature. The solution remains supersaturated for a long while --> crystallizes and makes rock candy.

Explain how rock candy is made, using solubility and saturated solutions.

Solvation is a surface phenomenon --> the more surface area of solute is exposed to the solvent, the faster it's dissolved

Explain the main idea behind the factors that speed up dissolving rates of a substance, and why those factors wouldn't affect an insoluble particle.

When the cap is on, the gas is contained, but when you leave the cap off, the pressure of the gas is released and over time will decrease --> solubility will decrease

Explain why carbonated beverages get "flat" if you leave the cap off for a long time in terms of Henry's Law.

A dynamic equilibrium exists between the solution and the undissolved solute (rate of solvation = rate of crystallization), provided that the temperature remains constant. As new particles from the solid are solvated and enter into solution, an equal number of already dissolved particles crystallize.

How can you describe the state of equilibrium in a saturated solution that contains undissolved solute?

As the temperature decreases, the solubility of the mineral decreases, causing crystallization.

Infer how the solubility of a mineral in a hot spring changes as the temperature decreases, explaining the crystallization of minerals at the cooled edges of the spring.

When heated water is dumped into a body of water, the increase in temperature lowers the solubility of oxygen in the water --> resulting in a lower concentration of DO in the water --> aquatic life severely affected

Infer why thermal pollution affects aquatic life.

a) temperature and the nature of solute and solvent

Q: Which of the following pairs of factors affects the solubility of a particular substance? a) temperature and nature of solute and solvent b) temperature and degree of mixing c) particle size and degree of mixing d) particle size and temperature

miscible

when 2 liquids are infinitely soluble in each other in all proportions (ex: water and ethanol)

unsaturated solution

contains less solute than a saturated solution at a given temperature and pressure

insoluble

inability of a substance to dissolve into a specific solvent

immiscible

when 2 liquids are insoluble in one other