Properties of Matter Mrs. Coyle Physical Science

How do we classify matter? Based on composition.

Pure Substance Matter that has a uniform composition. The properties of a pure substance are the same throughout.

Elements The simplest substances. Can not be separated into simpler substances by physical or chemical means. Made up of one type of atom. Building blocks of all matter. More than 100 known elements. Represented by chemical symbols

Si Silicon

Sulfur

Compounds When two substances are chemically combined, the resulting material has very different properties from the individual substances. (Ex: H 2 O) Made up of two or more simpler substances. Made up of two or more elements in a fixed composition.

H 2 O composition is fixed- compound Gaseous PhaseLiquid Phase

Copper (II) Choride CuCl 2

Mixtures

A physical blend of two or more substances is a mixture.

Mixtures -Homogeneous -Heterogeneous

Mixtures Homogeneous mixture (solution) Uniform composition throughout the mixture One phase

Example: Stainless Steel A homogeneous mixture of: -Iron (Fe) -Chromium (Cr) -Nickel (Ni)

Example: Gaseous Mixture Elements argon and nitrogen and a compound (water vapor).

Heterogeneous Mixtures Non-uniform composition throughout the mixture Two or more phases. Example: Oil and vinegar

Colloids, Suspensions and Solutions

Colloids A colloid contains some particles that are intermediate in size. Like solutions, colloids do not separate into layers. You also cannot use a filter to separate the parts of a colloid. The scattering of light is a property that can be used to distinguish colloids from solutions. Example: Milk, Fog.

Suspensions A heterogeneous mixture that separates into layers over time. You can use a filter to separate the suspended particles. Because the large particles can scatter light, suspensions are cloudy. Example: Sand and Water in a container, anything in a bottle that says" Shake well before using”.

Solutions A homogenous mixture. Do not separate into layers over time. The particles in a solution are too small to be trapped by a filter. Light passes through a solution without scattering light. Example: Windshield wiper fluid, Gatorade

Properties of a Substance Physical Properties Chemical Properties

Physical Properties Can be measured or observed without changing the composition of a substance. Describe the look, feel, state, odor, etc of a substance. Examples: Viscosity, conductivity, malleability, hardness, melting point, and density.

Physical Properties Viscosity: The tendency of a liquid to keep from flowing (its resistance to flowing). Conductivity: A material’s ability to allow heat to flow. Malleability: The ability of a solid to be hammered without shattering. Hardness: A way to compare the hardness of two materials is to see which material can scratch the other.

Physical Properties Melting Point: The temperature at which a a substance changes from solid to liquid. Boiling Point: The temperature at which a substance boils. Density: Is the ratio of the mass of a substance to its volume.

SubstanceStateColor Melting Point (C°) Boiling Point (C°) Density (g/cm 3 ) OxygenO2O2 GasColorless MercuryHgLiquidSilvery- white BromineBr 2 LiquidRed-brown WaterH2OH2OLiquidColorless Sodium Chloride NaClSolidWhite Example: Physical Properties

Separation Methods Use differences in the physical properties of the components of the mixture.

Example: Separate iron filings from sulfur using a magnet. What physical property difference is this taking advantage of?

Filtration: separates a solid from a liquid in a heterogeneous mixture What physical property difference does this process take advantage of?

Distillation: separates dissolved solids from a liquid, by using boiling and condensation.

What physical property difference does distillation take advantage of? The difference in boiling point between the two or more substances in the mixture.

Distillation of Crude Oil (Refining) Crude Oil is a mixture of Hydrocarbons

Distillation of Crude Oil

Chemical Properties and Chemical Changes

Chemical Properties Describe the tendency of a substance to transform into a new substance. Example: Magnesium reacts with oxygen to form magnesium oxide.

Magnesium Mg

Burning of Magnesium 2Mg+ O 2  2MgO

Examples of Chemical Properties Flammability: the ability to burn in the presence of oxygen. Reactivity: how readily a substance chemically combines with another substance.

Changes - Physical-Chemical

Physical Changes Physical change: a change in the physical properties of a substance. Composition does not change. May be reversible or irreversible. Examples: Reversible: Irreversible:

Chemical Changes Chemical change: the transformation of one or more substances into others. During a chemical change, a new substance is formed as atoms rearrange themselves into new configurations. Composition changes during a chemical change.

Burning of Methane

Burning of Methane CH 4 + 2O 2  CO 2 + 2H 2 O

Recognizing a Chemical Change: -production of a gas -color change -formation of a precipitate -energy exchange

Formation of a Precipitate Cu(OH) 2 Precipitate