Solutions

Chapter 8.1 & 8.2

Formation

Any states of matter - solid, liquid, or gas – can become part of a solution For a solution to form, one substance must dissolve in another 2 components:

solute – a substance whose particles are dissolved in a solution; its what you want to dissolvesolvent – the substance in which the solute dissolves

U put solute in solvent

solution - a homogeneous mixture of two or more substances Example: Salt Water

Which one dissolves? In what?

U put salt in water & it becomes a solutionIn a solution, the solvent is the substance in the greatest quantity or amount

Type of Solutions

Solute Solvent ***(you don’t have to copy this page)***

Gas Gas Air (solution of O2, CO2 and N2 )

Liquid Gas Water in air (water vapor or steam)

Gas Liquid Carbonated beverages like soda (CO2 in H2O)

Liquid Liquid Vinegar (acetic acid in water)

Solid Liquid Sugar water (sugar in water)

Solid Solid Stainless steel (chromium & nickel in iron)

Factors Affecting Rates of Dissolving

During the formation of a solution, collisions occur between particles of the solute and solvent Number of collisions can increase due to 3 things: surface area, stirring, & temperature.

3 ways to Speed it up

1 – break it up to increase surface area 2 - stir it up so it has more collisions w/ other particles 3 - heat it up so the particles move faster (Kinetic Theory of Matter!)

Solubility & Concentration There are limits to how much solute you can get to dissolve in a solvent solubility – the maximum amount of solute that dissolves in a given amount of solvent at a constant temperatureSolubility is usually expressed in grams of solute per 100 grams of solvent at a specified temperature concentration – amount of solute dissolved in a specified amount of solution

Solubility in 100 g of Water at 20˚C

Compound Solubility (g)

Table salt (NaCl) 36.0 g

Baking soda (NaHCO3)

9.6 g

Table sugar (C12H22O11) 203.9 g

How much is in it?

Solutions are described as saturated, unsaturated, or supersaturated, depending on the amount of solute in solution

Saturated

saturated solutions – a solution that contains as much solute as the solvent can hold at a given temperature When a solution is saturated, the solvent is “filled” with solute. If you add more solute & don’t increase the temperature, the solute will not dissolve in the solvent

Unsaturated

unsaturated solution – a solution that has less than the maximum amount of solute that can be dissolvedIf a solution is classified as unsaturated, you can add more solute and it will dissolve without having to increase the temperature

Supersaturated

supersaturated solution – a solution that contains more solutes than it can normally hold at a given temperature Supersaturated solutions are very unstable

Solubility Curve