Pure Substance A pure substance is a substance in which all the particles (atoms) are of one kind Gold (Au), Silver (Ag), Chlorine (Cl), Sodium (Na). In other words the atoms are all the same type which is what gives it its physical & chemical characteristics.

Element Elements are pure substances that cannot be separated into simpler substances by physical or chemical means. All the atoms of an element are of one kind. Elements have physical & chemical properties that help identify them because they do not change based on how much of the element there is.

Periodic Table The modern periodic table has space for 118 elements. Only 4 of the 118 have not been officially named. When the 119 th element is discovered the periodic table will have add its 8 th period or row.

Metals Generally shiny, solids at room temperature except for (Mercury which is a liquid (Hg)), good conductors of heat and electricity, malleable, and ductile.

Metals Common Examples: Gold, Aluminum, Copper, Zinc, Nickel, Lead, Sodium, Magnesium, Potassium, Iron, Calcium

Non-metals Generally dull, brittle, not ductile, poor conductors of heat and electricity. 11 are gases, 1 liquid (Br), and 6 are solid.

Non-Metals Common Examples: Sulfur, Carbon, Phosphorus, Bromine, Oxygen, Iodine, Hydrogen, Helium. Chlorine, Fluorine, and Nitrogen.

Metalloids Semi-conductors that have similar properties of Metals and Non-Metals. Some are shiny, some are dull. Some are somewhat malleable, some are brittle. Some conduct heat and electricity well, some do not.

Metalloids The most used metalloid is silicon and it is used in computer chips. Germanium and arsenic are also used in trace amounts in computer chips.

Metalloids Examples are Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, and sometimes Astatine.

Compounds Compounds cannot be broken down by physical means. They must be broken down chemically

Compound Properties The properties of a compound are usually different versus the reactant elements. Most reactions produce compounds with unique properties.

Example Carbon Dioxide CO °C Boiling point solid Carbon 4827°C Boiling point gas Oxygen -183°C Boiling point Water H 2 O 100°C Boiling point gas Oxygen -183°C Boiling point gas Hydrogen -253°C Boiling point Sodium Chloride NaCl 1413°C Boiling point Sodium 889°C Boiling point Chlorine -34°C Boiling point

Compounds you need to know for the EOG Carbon dioxide - CO 2 Water - H 2 O Salt - NaCl

Specific Ratio Compounds do not just join together in random fashion but by specific ratio, C 6 H 12 O 6, NaCl, H 2 O

Water: A Unique Compound Water- no living creature can live without odorless and tasteless water. It is the most important compound on Earth.

Water Properties 1.0 gm/ml density, expands when it freezes(very important in rock cycle) Can exist in solid, liquid, and gas at standard atmospheric pressure. High specific heat which helps regulate Earth’s temperature through the ocean absorbing heat. Is polar in structure.

Universal Solvent Water is considered the universal solvent because so many substances dissolve in water. Water is polar in its structure and charge. “Sticks to itself”.

Cohesion vs Adhesion Cohesion is the force that holds molecules of a single substance together. Water forms drops because of cohesion. Example: water to water. Adhesion is the force that holds molecules of different substances together. Example: water to towels.

Definitions Solvent- a substance in which something dissolves. Solute- a substance dissolved by a solvent. Dissolved- goes into solution. Example: Koolaid granular material is the solute and the water is the solvent, salt is solute and water is the solvent in salt water.

Definitions Dilute- small amount of solute vs solvent Concentrated- large amount of solute vs solvent.

Breaking Down Compounds Compounds are broken down ONLY through a chemical change. Can be accomplished by applying heat or an electric current.

Compounds in Nature Proteins are compounds found in all living things. Proteins are created from long chains of amino acids. Photosynthesis uses the compound carbon dioxide & water & sunlight to make the compounds called carbohydrates (glucose).

Photosynthesis 6CO 2 + 6H 2 O + sunlight energy = C 6 H 12 O 6 + 6O 2 Cellular Respiration C 6 H 12 O 6 + 6O 2 = 6CO 2 + 6H 2 O + ATP (energy)

Mixtures may be Homogenous- uniformly distributed particles, Kool-Aid in water, coffee, tea, coke Heterogeneous- unevenly distributed particles, ingredients on pizza, toss salad, cement mix, rock/sand mix in the coke bottle.

Separating Mixtures Can separate by physical means: Distillation, Filtering, or by spinning in a Centrifuge.

Distillation Separating by the different boiling points of the components. Examples: crude oil into gasoline, kerosene, jet fuel, and asphalt. Alcohol from fermented material and fresh water from salt water.

Centrifuge Spinning in a circle causing the most dense material to settle to the bottom. Separation blood platelets from plasma, separating different components of atomic particles (Iraq).

Centrifuge separates blood platelets

Mixtures Mixtures do not have definite ratio ( 1:1, 2:5, etc) of components. The components can vary in any proportion.

Mixtures 1- No change in the original properties of the components. 2- Separated by physical means. 3-Formed by using any ratio of components.

Elements Elements are pure substances that cannot be separated into simpler substances by physical or chemical means.

Three Major Element Types Metals Non-Metals Metalloids

Compounds A compound is a pure substance of TWO or MORE elements that are chemically combined (Bonded together). The smallest part of a compound is a molecule.

Compounds 1-Made of elements. 2-Change in the original properties. 3-Separated by chemical means. 4-Formed using a set ratio of components.

Mixture A mixture is two or more elements or compounds that are not chemically combined. Does not react to form a compound. Example: pizza is cheese, mushrooms, mushrooms, Canadian bacon, Canadian bacon, tomato sauce, and crust. You can pick out the individual components of a mixture. Each item in the mixture keeps it’s identity. Example: Toss Salad is lettuce, cheese, tomato, dressing, crust, and pickles.

Water

Carbon Dioxide

Sodium Chloride

Solutions Particles are evenly distributed throughout. Same appearance and properties throughout the mixture. Particles in a solution are so small they never settle out and cannot be separated by filtering.

Solutions

Solvent/Solvent Solute is the substance that is dissolved. Solvent is the substance solute is dissolved in. When two liquids or two gases are combined into a solution the substance with the greater amount is the solvent. Example: air (oxygen in nitrogen) or antifreeze (alcohol in water) or brass (zinc in copper).

Solute/Solvent

Solutions may be Solid in liquid (salt in H 2 O) Liquid in liquid (antifreeze) Gas in gas (Air O in N) Gas in liquid (soda CO 2 in H 2 O) Solid in solid (Brass=Cu in Zn)

Alloys Alloys are made by dissolving metals in metals. Our coins are generally alloys; penny is copper and zinc as we saw in the penny lab. Steel is carbon and other elements dissolved in iron. Our coin the nickel is copper and nickel.

Concentration Is expressed as grams solute/milliliter of solvent. Dilute is less solute per unit of solvent. Concentrated is more solute per unit of solvent.

35 grams salt in 175 ml of water what is the concentration? 55 grams sugar in 500 ml of water what is the concentration? 36 grams sugar in 144 ml of water what is the concentration? Which is the most concentrated and which is the most dilute?

Solubility Is the ability of solute to dissolve in solvent at a certain temperature and pressure. Most solids are more soluble in liquid as the temperature goes up (the solute particles are further apart). Most gases are less soluble in liquid as temperature goes up (the gas more easily escapes from the liquid).

Solubility Ways to increase solubility are: Mix or stir (get particles moving not clumped together) Heat (increase the particles average kinetic energy) Crush ( increase surface area)

Suspension A mixture of particles dispersed in a liquid or a gas but large enough they will eventually settle out. Can separate by passing through a filter. Examples: Snow globe, Italian Dressing, dirt particles in a container of water.

Suspension

Colloid A mixture that the particles sizes are between a solution and a suspension. Particles are dispersed throughout but are not heavy enough to settle out. Cannot be separated by filtering. Examples: milk, jello, stick deodorant, whip cream, butter.

Colloid

Diatomic Elements Are molecules of two atoms of the same element. Elements found is nature as diatomic are, H 2, O 2, N 2, F 2, Cl 2, Cl 2, and I 2.