Properties of Matter, Changes in Matter, and Mixtures of Matter Notes

Properties of Matter Substance = matter that has a uniform and unchanging composition Physical property = characteristic that can be observed or measured without changing a substance’s composition

Properties of Matter Examples of physical properties include: DensityBoiling point ColorMalleability TasteDuctility ShapeConductivity Mass Volume Odor Hardness

Extensive vs. Intensive Physical Properties Extensive properties depend on the amount of substance present. Examples: mass, volume, length Intensive properties do not depend on the amount of substance present. Examples: density, color, hardness Which ones are better for identification: extensive or intensive properties?

Chemical Properties An object’s chemical properties tell its ability to change or combine with one or more other substances

States of Matter State of matter simply describes whether an object is a solid, liquid, or gas. Solid = definite shape, definite volume, particles very close together, incompressible Liquid = takes shape of container, definite volume, particles can move past one another, incompressible Gas = takes shape of container, fills the entire volume of its container, particles very spread apart, easily compressed

States of Matter (cont.) Vapor = simply the term used when a substance that is usually a liquid or solid at room temperature becomes a gas.

Changes in Matter Physical change – this kind of change will alter a substance, but will not change its composition Example: changes of state (liquid to gas) Other examples: cutting, grinding, breaking, crushing, splitting

Changes in Matter Chemical change– process that involves one or more substances changing into new substances Examples: Rust, burning wood Evidence of chemical reactions (changes) If a new product forms which has different properties than the initial reactants, a chemical change has occurred.

Law of Conservation of Mass States that “mass is not created or destroyed during a chemical reaction” Mass reactants = Mass products Example #1 In an experiment, g of red mercury(II) oxide powder is placed in an open flask and heated until it is converted to liquid mercury and oxygen gas. The liquid mercury has a mass of g. What is the mass of oxygen formed in the reaction?

Law of Conservation of Mass Iron and Sulfur Conservation of Mass Demo

Mixtures of Matter Mixture = combination of two or more pure substances in which each pure substance retains its individual chemical properties Heterogeneous mixture = a mixture that does not blend smoothly throughout, individual substances remain distinct Homogeneous mixture = has constant composition throughout, has a single phase Also known as solutions

Mixtures of Matter Types of Solutions Gas-gas Gas-liquid Liquid-gas Liquid-liquid Solid-liquid Solid-solid (alloy)

Mixtures of Matter Methods to Separate Mixtures 1.Filtration – uses a porous barrier to separate a solid from a liquid 2.Distillation – separates substances based on boiling points Substance with lowest boiling point boils to a vapor, then is condensed back to a liquid and collected

Mixtures of Matter Methods to Separate Mixtures 3.Crystallization – results in the formation of pure solid particles of a substance from a solution containing the dissolved substance 4.Chromatography – separates components of a mixture based on their tendency to travel or be drawn across the surface of another material