ECM Notes

ELEMENTS

Pure Substance - material in which all basic particles are identical (ex. O_2,Al, H₂O, NaCl)

Element--- a pure substance that can not be broken down into smaller parts (ex. H, O₂, Al)

Can not be broken down by physical or chemical changes.

Only have one type of atom.

THREE CATEGORIES OF ELEMENTS

METALS

shiny

solids

conduct heat and electricity

METALLOIDS

some are shiny

can be brittle

some conduct heat and electricity

NON-METALS

solids are dull

most are gases

do not conduct heat and electricity

COMPOUNDS

Compound--- a pure substance of two or more elements that are chemically combined (ex. H₂O, CaCO_3,CO₂)

Elements joined in specific ratios. NaCl or H₂O

Compounds can not be broken down using physical changes!

Compounds can be broken down using chemical changes!

Properties are different from the elements that make it up!

TWO CATEGORIES OF COMPOUNDS

ORGANIC

INORGANIC

Contains carbon and many hydrogen elements
Associated with LIFE

Metals and nonmetals
No C-H bonds

Has properties different from its elements!

Sodium - soft, silvery white metal, reacts violently with water
Chlorine - poisonous, greenish-yellow gas
Sodium Chloride --> TABLE SALT, white solid, dissolves in water and is safe to eat!!!

MIXTURES

Mixture --- Two or more substances that are not chemically joined to one another (ex. Vegetable soup, sugar water, brass)

Two Main Types

Homogeneous – molecules are mixed up in an even distribution (every spoonful should be the same)

Heterogeneous - molecules are not mixed up in an even distribution (every spoonful will be different)

HOMOGENEOUS MIXTURES

Solutions – a mixture that appears to be a single substance

 Solubility – the ability to dissolve in another substance

 Solute – the substance being dissolved

 Solvent – the substance in which the solute is being dissolved

 Concentration – the amount of solute in a solution

 Water is considered a universal solvent

 Particles do not scatter light

 Ex: sugar water, lemonade, Kool-Aid , soda, air

Alloy -- a mixture of two metal

 Ex: brass (zinc and copper), steel (carbon and iron)

HETEROGENEOUS MIXTURES

Colloids – a mixture of tiny particles that are bigger than those in a solution, but smaller than in a suspension

 Do not settle out over time

 Scatter light

 Ex: Mayonnaise, milk, gelatin, whipped cream

Suspensions – a mixture in which particles are dispersed in liquid or a gas and will eventually settle out

 Particles can scatter light

 Can be filtered out using a filter

 Ex: snow globe, sand in a bucket of water, muddy water

Other Mixtures – mixtures with large particles that can often easily be seen

 Ex: tossed salad, pizza, gravel, sand

Interesting Mixture Facts

Smoke is a mixture of particles that are suspended in the air.
Tap water is a mixture of water and other particles. Pure water or H₂O is generally referred to as distilled water.
Many of the substances we come into contact with every day are mixtures including the air we breathe which is a mixture of gases like oxygen and nitrogen.
Blood is a mixture that can be separated by a machine called a centrifuge into its two main parts: plasma and red blood cells.
Mixtures can be liquids, gases, and solids.

PUTTING IT ALL TOGETHER

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