A lava lamp depends on the globs not being soluble. It alsodepends on the globs being about the same density as water. Ittook years to develop the right ingredients to make a lava lampwork.
Polar Molecules
Molecules like water that have positive and negative poles(like magnetic poles) are called POLAR. Molecules that donot have any negative or positive poles are called nonpolar.
Water’s Surface Tension
•The strong attraction water has toitself is due to the plus to minusattraction.
• Water tries to pull itself into aspherical shape.
•This attraction also accounts for what'scalled "surface tension."
•Water molecules lock together to forma skin where water meets the air.
• Insects take advantage of this surfacetension to stand on the surface.
Definition
Solubility is the ability of a gas, liquid, or solid todissolve in water (or sometimes another liquid).
The motto regarding solubility is "Like DissovlesLike.”
•Nonpolar soap Polar water
•dissolves nonpolar dissolves
•grease on hands polar sugar
•dishes. to sweeten
• the tea.
Attraction of Water Molecules
The plus end of water is attracted to the negative end of adifferent water molecule.
They align themselves + to - .
Water Dissolving A Polar Compound
•The substances that water isgood at dissolving are thosethat have a charge.
• Here is sodium chloride(table salt).
•Sodium has a net plus chargebecause chlorine has taken oneof sodium's electrons.
•This makes chlorine negativebecause it has an extraelectron.
Continued:
•The negative end of waterpulls on the sodium atom .
•The positive end of otherwater molecules pull onthe negatively chargedchlorine.
•Most salts like sodiumchloride are easily pulledapart by water.
Factors that Affect Dissolving Rate
Increasing the temperature usuallyincreases the solubility of solids inliquids. This means a greater averagevelocity for the particles.
It also allows them to move from oneposition to another more easily.
Stirring-brings more fresh solvent intocontact with more solute.
Grinding the solute into smallersize particles. Smaller particleshave more surface area than largersize particles
Nonpolar Molecules
•To the left is a chain of carbon andhydrogen atoms.
•We call these hydrocarbons. This one isabout 7 carbons long and is typical ofgasoline.
• The bottom image shows the charges ofa carbon atom attached to twohydrogens.
•You may notice that unlike water thecharge is divided evenly.
•This explains why water will not breakdown a nonpolar molecule.
•Ex. Water will not break down gasoline.
Concentrated OJ – No
water has been added
to this solution.
Diluted OJ – Water has
been added to this
solution.
Concentrations of Solutions
A concentrated solution has a relatively large (but non-specific) amount of solute dissolved in a solvent.
A dilute solution has a smaller quantity of solute dissolved.
Dilute Lemonade Concentrated Lemonade
Not as much sugar
dissolved as there More sugar dissolved
could be!!!! compared to the
other solution.
(Comparing the concentrations of dissolved sugar )
Examples of Concentrations in Solutions
Concentrations
Solute Less Than50%
Solvent More Than50%
Examples
Liquid
Liquid
Alcohol - Water
wine, beer, acetic acid
Solid
Liquid
Salt – Water
Saline, Sugar water,Hard water (CaCO3)
Gas
Liquid
Oxygen - Water
Carbonated water(CO2), ammoniasolution
Gas
Gas
Air =
oxygen -nitrogen
Solid
Gas
smog
Solid
Solid
alloy
brass
Making a Homogeneous Solution
Solute:
The substance in thesmallest amount
the one that dissolves ordisperses
Solvent:
Sugar
• The substance in the
larger amount
• Substance doing the
dissolving
Water:
universal solvent
Water isn’t always the solvent
Solution with alcohol as
solvent is called a
tincture.
Solution made of
two or more metals
is called an alloy.
Properties of a Suspension:
Suspension:
is a heterogeneousmixture with largerparticles.
particles are visible andwill settle out on standing.
Can be separated byfiltering.
Examples : muddy water,tomato juice, orange juicewith pulp
Muddy Water
Orange Juice with Pulp
Tomato Juice
Properties of a Colloid:
Colloid:
a heterogeneous mixturewith intermediate particlesize between a solutionand a suspension
Colloid particles may beseen in a beam of light(Tyndall effect)
Will not settle out.
Examples: dust in air,milk, fog, and jello.
Fog
Milk
Jello
Unsaturated, Saturated, and Supersaturated
Saturated : when a substance has dissolved in a solution and nomore of it will dissolve under normal circumstances (roomtemperature, normal pressure). It has reached equilibrium
Unsaturated : just points before equilibrium is reached, soyou can keep dissolving the substance into the solution. Thereis not as much solute dissolved in solution as it can hold.
Supersaturated: when the conditions are changed so that youcan dissolve more of the substance into the solution than it wouldallow under normal conditions. If the solution is brought back tonormal conditions, the substance will drop out of solution .
Tyndall Effect
Caused by reflection of light byvery small particles insuspension in a transparentmedium.
It is often seen from the dust inthe air when sunlight comes inthrough a window, or comesdown through holes in clouds.
Also, It is seen when headlightbeams are visible on foggynights
Miscible V’S Immiscible
When two liquids totallymix they are said to bemiscible.
An example of this wouldbe alcohol and water.
Ethanol and water are completely
miscible. No matter what ratio (%) they are dissolved.
When two liquids do notmix they are said to beimmiscible.
An example would be oiland water.
Solubility Graph and Solubility Curve
The solubility of a substance for a given temperature must bedetermined.
This is done by finding the mass of solute needed to make asaturated solution in a given amount of water for thattemperature(referred to as the solubility)
This is repeated for each of the temperatures .
The data is then plotted on a temperature/solubility graph andthe points are connected.
These connected points are called a solubility curve.
