“Compounds and Mixtures”

I- Identifying Compounds: A-Compounds

= substance formed by the chemical combination of two or more elements.

1-

Compounds always contain the same elements and the same ratio of elements.

EXAMPLES:

Rust =

Fe 2 O 3

two iron atoms and three oxygen atoms, Water =

H 2 O

Two hydrogen atoms and 1 oxygen.

2- Chemical Formula

= a chemical compound. It includes symbols of the element and the ratios of atoms.

EXAMPLES: H 2 O, NaCl, and Fe 2 O 3

the small number is called a

subscript

if no subscript there is one atom of that element.

3.

Compounds unlike elements can be broken down into its elements. Since they are chemically combined they need to be broken down chemically.

a-Heating

will separate some compounds.

b-Electrolysis =

passing electricity through the compound.

II-Identifying Mixtures: A-Mixtures

:

substances that mix together but two or more

do not

join chemically

.

1-

Can be either compounds or elements.

EXAMPLES:

 Soil  Sand  Air  Milk  Toothpastes

2- Separating Mixtures: a-

Easily using

filters

.

b- Naturally

= Oil and water.

c-

Evaporate

water = salt, sugar, &

Formed by Bonds Number of substances Separate Compound

Elements Chemically Fixed amounts Hard

Mixture

Elements or Compounds Not Chemically Random amounts Easy

III- Types of Mixtures:

A- Solutions:

Type of mixture.

EXAMPLE:

Sugar Water.

1-

Even though you can not see the sugar it still makes the water sweet.

2-Dissolving: SUGAR-WATER The sugar molecules attract to the H 2 O molecules. Filling the spaces between the water molecules.

3- Soluble =

when one substance can be dissolved in another substance.

a- Solvent =

the substance that dissolves other materials.

H 2 0 b- Solute =

the substance that is being dissolved.

Sugar

4- Describing Solutions: a- Dilute =

small amount of solute.

Weak coffee b- Concentrated =

large amount of solute.

Strong coffee c- Saturated = No

more solute can be dissolved at that temperature and pressure.

 Heat the solution up you can increase the solvents ability to dissolve more solute.

5- Solubility =

describes the amount of solute necessary to saturate a definite amount of solvent at a given temperature

IV- Suspensions = Another Kind of Mixture

A- Suspension:

a mixture in which the particles of one substance become scattered through out another

without

dissolving.

EXAMPLES:

Oil and Water.

Oil Water

1-Types of Suspensions:

 Solid in Liquid “Sand and Water”  Solid in Gas “Smoke”  Gas in Liquid “Shaving Cream”  Liquid in Liquid “Oil and Water

B- Colloid =

Suspension of small particles that remain mixed.

Example: MILK 1-Emulsion

special type of colloid that consists of one liquid suspended in another liquid.

EXAMPLE:

Mayonnaise

a- Emulsifier

is the substance that keeps the particles of liquid mixed.

“Egg Yolk”