Matter is GrainyMatter is Grainy

2000 B C 1805 1990s

Sand on Atomic Tunneling

a beach Theory electron

microscope

Matter

Mixtures Pure Substances

heterogeneous homogeneous element compound

Mixture Loose combination of materials Variable composition Components retain their properties Can be separated by using

differences in properties of components

Heterogeneous or homogeneous

Heterogeneous Non-uniform mixture Two or more components or phases

clearly visible Mud and water, chunky peanut

butter, Italian dressing are examples Heterogeneous mixtures are called

suspensions

Homogeneous Uniform mixture Appears to contain only one phase or

component saltwater, creamy peanut butter, non-

carbonated beverages are examples Homogeneous mixtures are called

solutions

Pure Substance Definite, non-variable composition Homogeneous Characteristic set of properties Elements or Compounds

Element Cannot be broken down chemically

into simpler substances Homogeneous Characteristic set of properties Contains only one type of atom

Compound Can be broken down chemically into

simpler substances Homogeneous Characteristic set of properties which

radically differ from the pure elements in it

Contains two or more types of atoms chemically combined

Binary-two elements, tertiary-three elements, quaternary –four elements

Alloy An alloy is a solid solution A homogeneous mixture of metals 18 carat gold, sterling silver, steel,

dental amalgums are all examples They are usually mixed while molten,

then solidified

Solution is a homogeneous mixture of a solute and a solvent Solute is the dissolvee Solvent is the dissolver In aqueous solutions, the solvent is

water

To make a mixture, just mix the components together

They keep their characteristic properties

How do you separate a mixture? Use differences in the properties of

the components

Separating Mixtures Distillation- separate solutions Filtration- separate suspensions Chromatography- separate solutions Decanting- separate suspensions

Distillation• Uses differences in boiling point to

separate the components of a solution( non-volatile solute)

• Heat the solution in a flask• Condense the vapor and collect the

liquid in a new container• Solid solute remains in the boiling flask• Used to make distilled water

Fractional Distillation• Uses differences in boiling point to separate the

components of a solution of liquids

• Heat the solution in a flask• Force the vapor up a tall column• Higher boiling liquids recondense and don’t reach the

condensor• Lowest boiling liquid’s vapor gets condensed and

collected• Then the next lowest boiling liquid can reach the

condensor and be collected.• This continues until all the liquids have boiled off and

been collected• Use to refine petroleum into gas , gasoline, kerosene,

diesel, etc.

Decanting • Pour off the liquid from a suspension

leaving the solid on the bottom of the container

• Used in the salt sand separation lab• Wine sits in a decanter before it is

poured at the table into glasses.

Filtration • Pour off the liquid from a suspension

through a filter in a funnel and collect the liquid in a container

• Solid stays on the filter paper• Sediment free liquid(filtrate) collects in

container under funnel

Chromatography • Put a dot of ink on a long strip of filter paper• Hang the paper on a rod on top of a beaker with

some water(or other solvent)• The bottom of the paper should hang in the water• Water travels up the paper and carries the dyes in

the ink with it.• Lighter (Mass)dyes travel farther up the paper,

faster than heavier dyes, and they are separated by mass on the strip

• Modern gas chromatographs are used in forensics to analyze liquids for different solutes contained in solution

Colloid • Size of particles in solvent are between

those in a suspension and those in a solution

• As a result, they don’t settle(Mud settles) and are hard to filter(cannot filter solutions)

• Tyndall Effect- colloidal particles are big enough to scatter light and the beam of light can be tracked through the solution. Solutions don’t reflect light.

To make a compound, a chemical reaction must occur which bonds the atoms of the two elements together

How do we know a reaction has occurred?

Hydrogen gas + oxygen gas are sparked Flames shoot out of balloon and water

vapor is formed In a chemical change, the product has new

properties(unlike the original materials) and a noticeable energy change is observed

In the formation of water, energy is released to the surroundings.

Heat comes out of the reaction- exothermic process

Reactions like these are called exothermic

Do all reactions release energy when they occur?

Some(photosynthesis) use up energy when the react

Heat goes into the reaction- endothermic

In exothermic reactions, the temperature goes up

Burning a log in a fireplace gives off heat to the room, room temperature goes up

In endothermic reactions, energy is taken from the surroundings and stored in products

An endothermic reaction lowers the temperature as it runs

Physical changes also involve energy changes, both endo and exothermic

Melting water requires an input of energy(endo) with no change in temperature of the ice- water mixture, but it is very small by comparison to the chemical change which formed the water

Likewise boiling water requires an input of energy(endo ) with no change in the boiling water’s temperature. It is larger than for melting, but still very small compared to the chemical change.

Freezing water and condensing steam release(exo) exactly the same amount of energy put in to melt and boil them

Roasting can be used to break up compounds of fairly stable elements

Iron, copper, mercury are made in this fashion by roasting ores(oxides) of these metals

Electrolysis is used to break up compounds of unstable elements

Electrolysis is passing an electric current through the material

Water can only be broken up into hydrogen and oxygen by electrolysis

There are four indicators that a chemical change has occurred

Only one of them needs to be present for the change to be chemical

A noticeable energy change A change in the color Formation of a precipitate(ppt) Formation of a gas