Warm Up

1. A small amount of a strong smelling sulfur compound is dissolved in natural gas to give gas a detectable odor. Which substance is the solvent?

2. True or False: A mixture has a set ratio of components.

3. Carbon dioxide is a gas at room temperature, but the element carbon is a solid. How can these two substances be so different?

Elements A substance that cannot be separated or

broken down into simpler substances. Pure substance – only has one type of particle

(atoms). Elements are found on the periodic table

111 elements known

Elements

Every atom in a piece of gold is the same, no matter where it is found.

Every atom of iron is the same spoon, steel rod, meteorite

I can describe the characteristics of elements, and give examples.

Properties of Elements Characteristic properties – do not depend on

the amt. of the element present. Boiling point, melting pt., density, reactivity

with acid, color, hardness, flammability Can be used to identify elements

Properties of Elements

Identified by their physical and chemical properties

Categorized by similar properties Metals, nonmetals, or metalloids

Classifying Elements1. Metals

Shiny, conduct heat and electricity, malleable, ductile

All are solid except mercury Examples: copper (Cu), tin (Sn), lead (Pb),

iron (Fe), gold (Au), mercury (Hg)

Classifying Elements2. Nonmetals

Opposite of metals dull, poor conductors heat and electricity, brittle, not

malleable, not ductile Can be solid, liquid, or gas

Examples: sulfur (S), iodine (I), neon (Ne), chlorine (Cl), oxygen (O), hydrogen (H)

Classifying elements3. Metalloids

Properties of both metals and nonmetals Semi-conductors

Some shiny, some dull, somewhat malleable and ductile, some conduct heat and electricity

Solids Examples: boron (B), silicon (Si), germanium (Ge), arsenic (As),

antimony (Sb), tellurium (Te)

I can distinguish between metals, nonmetals, and metalloids.

Substances

Matter that has the same composition and properties throughout is called a substance.

• When different elements combine, other substances are formed.

Substances

Contains only one particle

Can exist in 3 states of matter

Can be elements or compounds

Picture from http://www.ilpi.com/msds/ref/gifs/statesofmatter.gif

Compounds A compound is a substance

whose smallest unit is made up of atoms of more than one element bonded together.

• Compounds often have properties that are different from the elements that make them up.

• Examples: Water, salt, sugar

H20 is the chemical formula for water, and H2O2 is the formula for hydrogen peroxide.

The formula tells you which elements make up a compound as well as how many atoms of each element are present.

Compounds Have Formulas

How to read a formula

HH2200This is a subscript. It tells us how many atoms of that element exist in one unit of that compound.

Hydrogen is made of 2 H atoms and 1 O atom.

No subscript is used when only one atom of an element is present.

Let’s try it… Using your white board tell how many atoms

there are in each element. Sulfuric Acid H2SO4

2 Hydrogen 1 Sulfur 4 Oxygen

Hydrogen Peroxide H2O2

2 Hydrogen 2 Oxygen

And some more formulas… Carbon Dioxide COCarbon Dioxide CO22

1 Carbon 2 Oxygen

Carbon Monoxide COCarbon Monoxide CO 1 Carbon 1 Oxygen

Calcium Carbonate Calcium Carbonate (Found in shells, eggshells, antacid) (Found in shells, eggshells, antacid) CaCOCaCO33

1 Calcium 1 Carbon 3 Oxygen

Compound Review  A pure compound has the same elements

and the same amount of elements all of the time

Elements are chemically combined Compound properties are different from the

properties of the elements They cannot be separated physically Physical properties such as boiling point or

melting point of pure substances are do not change

Mixtures

A mixture is a combination of two or more substances where there is no chemical combination or reaction.

A mixture is a combination of two or more substances where there is no chemical combination or reaction.

Mixtures combine physically in no specific proportions. They just mix.

Solids, liquids and gases can be combined to

create a mixture.

Mixture Types

MIXTURES MAY BE HOMOGENEOUS OR HETEROGENEOUS

Homogeneous Mixtures

Homogeneous Mixtures:

The prefix: "homo"- indicates the same

Have the same uniform appearance and composition throughout

Solutions

SOLUTIONS are homogeneous mixtures

What is a solution? A solution is a

mixture of two or more substances.

At least two substances must be mixed in order to have a solution

A solution has two parts The

substance in the smallest amount and the one that DISSOLVES is called the SOLUTE

The substance in the larger amount is called the SOLVENT - it does the dissolving

IN most common instances water is the solvent

                        

Examples of solutions

Salt water Clean Air Vinegar

Heterogeneous Mixtures:

The prefix: "hetero"- indicates difference

A heterogeneous mixture consists of visibly different substances or phases

Two or more parts can be seen

Examples:

Pizza Sandwich Chex Mix

Suspensions

A SUSPENSION is a heterogeneous mixture of large particles

These particles are visible and will settle out on standing

Examples of suspensions are: fine sand or silt in water or Italian salad dressing

Compounds vs Mixtures

CompoundsCompoundsMixturesMixtures

Combine chemically forming molecules

Not chemically Not chemically combinedcombined

Combine in set proportions

Can combine in any Can combine in any proportionproportion

Separated chemically Separated Separated physicallyphysically

Comparing Elements, Compounds & Mixtures

Elements Compounds Mixtures

What are they made up of?

Can they be broken down? If yes, how?

Do they keep or lose their original

properties?

Draw what the particles look like.

Identify the following with as many terms as apply

1. Table salt

2. Salad

3. Mayonnaise

4. Italian dressing

5. Pepsi

6. Oxygen

7. Hydrogen

8. Water

Mixture

Element

Compound

Suspension

Colloid

Solution

Homogeneous

Heterogeneous