Bell Ringer  What is Chemistry?  How does affect your life?

Matter Matter is anything that:  Has mass&  Takes up space  What is Matter?

 Different materials  different properties  different materials have different compositions (i.e. different stuff)  Clothing labels  no cleaning process works for all materials. Matter

 Matter is divided into 2 categories: Matter

Matter that always has exactly the same composition.  Every sample has the same properties  Examples: Table salt and table sugar Pure Substances  Two categories of pure substances: Elements Compounds. Matter

 Cannot be broken down into simpler substances.  Fixed composition  Contains only one type of atom.  The atoms of each element are unique. Elements ( First Category of Pure Substances)

Examples of Elements you may have heard of:  Aluminum - Most soft drink cans made from it.  Carbon - main element in pencil marks.  Oxygen and Nitrogen - main gases in the air.  Bromine and Mercury - two elements that are liquids at room temperature (Most elements are solids at room temperature.) Elements

Symbols for Elements Chemical symbols have one or two letters  First letter is always CAPITALIZED  If there is a second letter, it is lower case C represents carbon. Al represents aluminum. Au represents gold. (The Latin name for gold is aurum) Elements

Symbols for Elements are universal Even when the names are different in different languages N is the symbol for the element we (American English speakers) call nitrogen:  French word is azote  German word is stickstoff  Spanish word is nitrógeno in Mexico. Elements

Pictures of pure elements you might encounter (most elements are not found in pure form) Elements AluminumCarbonGoldIodine

 A compound contains two or more elements joined in a fixed proportion. Compounds (Second Category of Pure Substances) Compound is: Made from two or more simpler substances Can be chemically broken down into those simpler substances.

Properties of a compound are different from those of the substances from which it is made. Example: Water – composed of H and O. Oxygen and hydrogen are gases at room temperature Water is a liquid at room temp. Hydrogen can fuel a fire Oxygen can keep a fire burning Water does not burn Compounds

Another Example: Sodium Chloride, composed of Na and Cl. (common table salt) Sodium and Chlorine are highly reactive, toxic (poisonous) materials. Sodium Chloride is necessary for life Compounds

Matter

If you make salsa, a recipe can guide you. You can use exactly the amounts in the recipe, or you can adjust the ingredients to your own taste. Salsa is a mixture. Each batch may be slightly different. Mixtures

Composition of a mixture is not fixed.  The properties of a mixture are less constant than the properties of a substance.  The properties of a mixture can vary  May vary in different parts of the mixture.  May vary when made at different times.  Some properties of the individual substances may be retained. Mixtures

Heterogeneous Mixture substances are noticeably different from one another. Homogeneous Substances are so evenly distributed that it is difficult to distinguish one substance from another. Two Types of Mixtures

The sand is a heterogeneous mixture of different kinds of grains. The spoon is stainless steel, a homogeneous mixture of iron, chromium, and nickel. Mixtures - Heterogeneous Example

Mixtures are classified based on size of largest particles  a solution (homogeneous)  a suspension (heterogeneous)  a colloid (it depends!) Solutions, Suspensions, and Colloids The size of the particles in a mixture has an effect on the properties of the mixture.

Mixtures

Solution  Dissolves  (tiniest particles are thoroughly mixed together)  Homogeneous mixture  Solute – the substance that is dissolved.  Solvent – the substance that does the dissolving.  Example: Lemonade  The sugar and lemon juice are solutes  The water is the solvent Solutions, Suspensions, and Colloids

Solubility = substances’ ability to dissolve.  Soluble means it will dissolve.  Example, Salt is soluble in water.  Insoluble means it will NOT dissolve.  Example, Oil is insoluble in water. Solutions, Suspensions, and Colloids

Suspension  Heterogeneous mixture  Separates into layers over time.  Example: muddy river water Solutions, Suspensions, and Colloids

Colloids Particles’ size between the small particles in a solution and the larger particles in a suspension.  Particles are mixed together, but not dissolved.  Won’t separate into layers (same as a solution)  Cannot separate parts with filter  Often appears Cloudy.  Examples: Fog, Smoke, Foam, Latex paint Solutions, Suspensions, and Colloids

Alloys  Metal Solutions  Solids that are dissolved in solids.  Examples:  Gold Jewelry: solid solution of gold & copper  Brass: copper and zinc solid solution  Sterling Silver – contains small amounts of copper in solution with silver  Stainless Steel: alloy of chromium and iron

These liquids represent three categories of mixtures: Windshield wiper fluid is a solution. Muddy water collected from a swamp is a suspension. Milk is a colloid. Solutions, Suspensions, and Colloids

Mixtures