Chemistry: the study of composition, structure, and properties of matter* and the changes it undergoes.

Elements and Compounds atomsAll matter is composed of atoms. –Copper pipe is made of copper atoms. –Oxygen gas is made of oxygen atoms. An element is a pure substance made of only one kind of atom. –Carbon is an element made of only carbon atoms. Atoms of two or more elements bond together to make compounds. –CO 2 (___ carbon atom and ___ oxygen atoms) –H 2 O 2 (___ hydrogen atoms & ___ oxygen atoms)

Chemical Formulas C 6 H 12 O 6 6 Carbon atoms 12 Hydrogen atoms 6 Oxygen atoms

Matter Mixtures Pure Substances Homogeneous (air, sugar in water) Heterogeneous (wood, blood) Elements (gold, oxygen) Compounds (water, salt, sugar) Classification of “Solutions”

Mixtures vs. Pure Substances MIXTURES Blend of two or more types of matter (each retains its own identities and properties.) Sugar-Water…is both sugar and water. Tastes like sugar and tastes like water. Examples: grape juice (water and sugar) PURE SUBSTANCES Every sample has exactly the same properties and came composition. –Pure water is always 11.2% hydrogen and 88.8% oxygen.

Homogeneous vs. Heterogeneous Mixtures Homogeneous The same throughout… every part is evenly distributed. Examples: –vinegar (water and acetic acid) “HOMO” : the sameHeterogeneous Not the same throughout… every part is not evenly distributed. Examples: –Salad (tomatoes, lettuce, olives, carrots, etc.) “HETERO” : different

Making a Mixture: “Mixing” Miscible: able to be mixed (liquids only) EX. Gasoline is a mixture of about 100 liquids. Immiscible: not able to be mixed (liquids only) EX. Oil and water cannot mix. Gases can mix with liquids also. An example is a carbonated drink like Pepsi. CO 2 + sugar + water + flavorings +  Pepsi CO 2 + sugar + water + flavorings + Awesome  Pepsi

Separation of Mixtures DISTILLATION 1.Boil mixture. 2.Liquid boils off, leaving solid minerals behind. 3.Collect the boiled vapor in a condenser. 4.Collected liquid is pure(er). Ex: Seawater FILTRATION 1.Pour mixture onto a mesh, like filter paper. 2.Liquid passes through paper. 3.Solid is left on the paper. Ex: Coffee filters

Physical Properties A characteristic that can be observed or measured without changing the identity of the substance. Examples: boiling and freezing points Physical Change: does not involve a change in identity of the substance…cutting, melting, boiling, freezing, dissolving. Change of State: physical change from one state to another. Solid  Liquid (Melting) Liquid  Solid (Freezing) Solid  Gas (Subliming) Gas  Solid (Deposition) Liquid  Gas(Evap./Boil) Gas  Liquid (Condensing) SOLID - LIQUID - GAS - PLASMA

Physical Properties Other Physical Properties Include: - strength - hardness - magnetism - reflectivity - melting point (temp at which it boils) - melting point (temp at which it melts) - density

What is Density? Density: a measurement of how much matter is contained in a certain volume. Calculate Density Calculate Density D = Mass Volume Volume D M V ***Test: Density of Water: 1.00 g/mL

Density Practice Problems Mass (g)Volume (mL)Density (g/mL) ? ? 3.? ? ?5.0

Density Practice Problems Mass (g)Volume (mL)Density (g/mL)

Density Practice Problems Mass (g)Volume (mL)Density (g/mL) ? ? ? ? ? 6.? ? ? ? ?6.01

Density Homework Problems Mass (g)Volume (mL)Density (g/mL) ? ? ? ? ? 6.? ? ? ? ?7.23

Weight vs. Density Density: a measurement of how much matter is contained in a certain volume. Weight: the measurement of gravity on an object’s mass…”how heavy”. Weight: the measurement of gravity on an object’s mass…”how heavy”.

Physical States of Matter SOLID: –Definite Shape –Definite Volume –Particles move slowly and are close together Examples –Sodium metal (Na) –Ice (H 2 O) –Gold at room temp. (Au)

Physical States of Matter LIQUID: –No Definite Shape –Definite Volume –Particles move a little faster than solids and more freely. Examples –Mercury (Hg) –Water (H 2 O) –Gold at high temp. (Au)

Physical States of Matter GAS: –No Definite Shape –No Definite Volume –Particles move very quickly and are far apart. Examples –Neon (Ne) –Steam (H 2 O) –Chlorine gas (Cl 2 )

Physical States of Matter PLASMA: –High Temperature –Atoms lose electrons easily Examples –Sun –Fluorescent Bulbs

Chemical Properties… …relate how chemicals undergo change. Chemical Change (reaction): when substances are converted into NEW substances. Reactants REACT. Products are PRODUCED. reactant + reactant  product carbon + oxygen  carbon dioxide C + O 2  CO 2

Chemical Properties… …relate how chemicals undergo change. Other Chemical Properties Include: - Reactivity (how readily a reaction will occur) - Flammability (ability to burn) - Tarnishing - Reacting with water, oxygen, acids, bases…

Chemical Changes …can be detected. Indications of a Chemical Reaction: 1. Change in odor or color. (burnt food) 2. Fizzing or Foaming (Alka-Seltzer) 3. Sound, heat, or light (TNT)

Review P (Questions 1 – 21; 24 – 27) - Do not write the question. Just the answer. - Do not write the question. Just the answer. - Vocabulary on p.69 will be on the test. - Vocabulary on p.69 will be on the test.