Section 1 Classification of Matter Chapter 18 Section 1 Classification of Matter

Two Ways to Classify Matter Matter can be classified as either a pure substance or a mixture. A pure substance is a material that cannot be broken down without changing its properties.

Three Pure Substances #1 Elements Elements: a substance made of the same type of atom (see p. 591 for periodic table) Elements cannot be broken down further without losing that element’s properties. Examples of elements: Oxygen, He, Carbon, H

Americium Gold Aluminum Tungsten Titanium Lead

Three Pure Substances #2 Compounds Compounds: Two or more different elements combined. Properties of a compound may be very different than the elements in it (i.e. NaCl) Examples of compounds: C6H12O6,, NaCl, CO2,

Three Pure Substances #3 Molecule Molecules: Two or more atoms combined. This means all compounds are molecules, but not all molecules are compounds. Examples of molecules: O2, H2, , CO2, C6H12O6,,

Classify Each as Element or Compound Iron HCl (hydrochloric acid) Silver H2O (water) Calcium Neon CO (carbon monoxide)

Mixtures Another way to classify matter is a mixture. A mixture is a blending of two or more materials that do not form compounds. They can be easily separated. There are two types of mixtures. Homogeneous mixtures: these have an evenly mixed uniform composition Heterogeneous mixtures: an uneven, non-uniform composition

Homogeneous Mixtures One type of homogeneous mixture is a solution. A solution is when one substance is dissolved into another. Solutions often appear to NOT look like mixtures. The item that is dissolved is called the solute. The material that the solute dissolves into is called the solvent.

Solution Examples Salt water Vinegar Lemonade Earth’s atmosphere Kool Aid Alloys

Heterogeneous Mixtures One type of heterogeneous mixture is a suspension. Suspension: two or more ingredients combined with very visible particles. In a liquid suspension, sometimes these particles will separate when left standing Suspensions can be separated using a filter.

Examples of Suspensions Italian dressing Muddy water Chicken soup

Colloids A colloid is a mixture that falls between homogeneous and heterogeneous. Colloids can appear transparent, cloudy, or opaque. Particles that make up colloids can be similar to solutions. Colloids cannot be separated with a filter. Tyndall Effect: when passing a light through a colloid, it will scatter the light.

Examples of Colloids Fog Smoke Milk Hair Gel Shampoo

Ch 18.1 Matter Analysis-Date__ Name________________ Hr__ Copy & answer using sentences. Show work. Explain differences: element & mixture Explain differences: compound & mixture Explain differences: colloid & suspension Why do words “shake well before using” tell that something is a suspension? A fabric mixture has 10% polyester+90% cotton. How many g cotton in 500 g fabric?

Properties of Matter Chapter 18 Section 2

Physical Properties Physical Properties: property that can be observed without changing the identity of a material Examples: Density, melting point, boiling point, ductility, magnetism, shape, odor

Chemical Properties Chemical Property: property that would change the identity of a material while observed Examples: Flammability, oxidation, pH

Chemical Changes vs. Physical Changes A chemical change is when a new substance forms and the old is altered. A physical change is when a substance changes size, shape, or state of matter.

Classifying chemical changes Look for these pieces of proof for chemical change: Smoke Bubbles Accidental change in color Formation of heat (EXOTHERMIC reaction) Sudden lower temp. (ENDOTHERMIC reaction) Odd odors

Classifying Physical Changes Remember, the original material is still there! Look for the following: Melting Evaporating/Boiling Freezing Condensation Any changes in size!

Classify the following changes: Crack an egg Fry an egg Bend a spoon Bleach on clothing Baking cookies Rust on metal Tarnish on a silver spoon Getting a haircut Leaves turning red in the fall Gasoline burning

Law of Conservation of Mass In any type of change, the total amount of mass NEVER changes.

Mass Conservation Example With chemical reactions, total mass of reactants equals total mass of products. If 18 g of hydrogen completely reacts with 633 g of chlorine, how many grams of HCl are formed? H2 + Cl2 = 2HCl Solve for HCl : ? g H2 + ? g Cl2 = ? g HCl Substitute values: 18g + 633g = 651 g HCl

Ch 18.2 Matter Analysis-Date__ Name________________ Hr__ Copy & answer using sentences. Show work. Why is evaporation a physical change? List 4 physical properties for a liquid. Why is flammability a chemical property? Explain Law of Conservation of Mass for chemical changes like burning wood. If 417.96 g of Bi react completely with 200 g of F, how many g of BiF3 form?