The Science of Chemistry

Before chemistry there was….. Alchemy

Alchemy: A medieval science and philosophy aiming to achieve: 1. Transmutation of base metals (like lead) into gold

Alchemy 2. Discovery of a universal cure for disease

Alchemy 3. Discovery of a way to prolong life

Has modern science achieved these things? Wealth for all? Cure for disease? Prolonged life?

Why is Gold valuable? Rare Pretty Soft, easy to shape Resists corrosion Chemically unreactive

The science that studies the structure, composition, and properties of substances and their transformations (Webster)

What are the simplest substances? The ELEMENTS ( only about 90 occur naturally, 114 discovered) Listed in the Periodical Table Basic building blocks for all other more complex substances (compounds) found in the universe

Abundance of common elements in the Universe 60% Hydrogen H element #1 37% Helium He element #2 3% elements # 3-90

Abundance of elements on Earth (crust and atmosphere) 35% iron 30 % oxygen 15 % silicon 13% Magnesium 2.4% nickel 4.6% others

Origin of the Elements

Big Bang billion years ago Matter and energy scatter, expand, and cool Matter condenses to form galaxies, Element Hydrogen forms Stars form in galaxies. In stars, H fuses to form Helium and energy More fusion allows heavier elements to form

We are all star dust……

Matter Anything that has mass and takes up space (volume) What is NOT matter???

Classification of Matter

Matter Can it be separated by physical means? If yes….

Then you have a Mixture

Physical ways to separate a mixture Filtering (particle size) Distillation (boiling point) (dissolved solid)

Physical ways to separate a mixture Chromatography (attraction to paper)

Is the mixture uniform throughout? IF yes, it is HOMOGENEOUS

If no, then the mixture is Heterogeneous

Homogeneous vs. Heterogeneous mixtures

Matter Can it be separated by physical means? Mixture Is it uniform throughout? Homogeneous Gatorade Bronze Brass Homogenized beverages Heterogeneous Dirt Sea shells Rocky road ice cream Non-homogenized beverages Substance YESNO YESNO

If matter can NOT be separated by physical means…. It is a SUBSTANCE If the substance can’t be broken down, it is an ELEMENT Elements are made of only one type of atom Ex. Aluminum, carbon, oxygen

SUBSTANCE If the substance CAN be broken down, it is a COMPOUND, made of two or more different kinds of atoms chemically bonded together. Ex. Water (2 Hydrogens and 1 oxygen)

Matter Can it be separated by physical means? MIXTURE Is it uniform throughout? Homogeneous Gatorade Bronze Brass Homogenized beverages Heterogeneous Dirt Sea shells Rocky road ice cream Non-homogenized beverages SUBSTANCE Can it be broken down? COMPOUND WATER H20 SALT NaCl ELEMENT Aluminum Graphite (Carbon) YESNO YESNOYesNO

ELEMENTS can be…. MONATOMIC : single atoms Al DIATOMIC : two of the same atom bonded together in pairs O 2 POLYATOMIC: three or more of the same atom bonded together O 3

7 Diatomic Elements

Particles of Matter

Review What is…… MATTER SUBSTANCE MIXTURE ELEMENT COMPOUND HETEROGENEOUS VS. HOMOGENEOUS

CHEMISTRY: THE STUDY OF MATTER Did you know that…….. One of the most popular “foods” in the United States is an entirely SYNTHETIC (man-made) mixture. Can you guess what it is?

SODA The average person consumes 40 GALLONS (!) of soda each year Mixture: carbonated water sweetener, acids, flavorings, caffeine

States of Matter GAS LIQUIDSOLID

Physical Properties of Matter The properties of a substance that can be demonstrated without changing the composition of the substance Size (length, volume) Density Mass Color

Physical Properties Melting Point Ex. Ice (solid water) starts to melt to liquid water at 0 degrees Celsius Boiling Point Ex. Water boils into steam at 100 degrees Celsius

Physical Properties Malleability: can be pounded into a new shape without breaking Metals are malleable

Physical Properties Iron is malleable Fe

Physical Properties Ductility Can be pulled into long wires without breaking Metals are ductile

Physical Properties Crystal Shape Reflects the regular arrangement of atoms in the solid

Physical Change A change in the sample of matter that does not result in a NEW substance: Phase Changes Changes in shape Solid liquid gas

Chemical Properties of Matter How matter behaves when it changes into a NEW substance. EX. Iron rustssilver tarnishes Milk sourssugar ferments eggs rotleaves turn paper burns

Chemical Change Substance changes into a NEW substance. This change is often an irreversible and permanent change in composition

Burning

Tarnishing

Rusting

Oxidizing

Chemical Reaction Chemical changes mean a chemical reaction has occurred REACTANTS PRODUCTS old substances become new substances Sodium + Chlorine sodium chloride (table salt) Na + CL NaCL

Test Review Know names and symbols of common elements NameSymbol AsSodium CaIron MnTin CuGold KLead

Test Review Matter

Classify the following samples of matter

Classify the following samples:

Classify the particles of matter

Identify the following changes as Physical or Chemical

Fe

Identify the following changes as Physical or Chemical

Periodic Table Review 1.Elements are arranged according to______ 2.Vertical columns are called________ 3.Horizontal rows are called ________ 4.There are ______ periods in the table 5.Most elements are classified as _____ 6.Where are the transition metals? 7.What are the metalloids?

Periodic Table Review 1.Describe 3 properties of metals 2.Describe 2 properties of non metals 3.Group 2 metals are called____________ 4.Group 17 non metals are called _______ 5.What two elements are liquid at room temperature? 6.How can you tell if a compound contains a transition metal?