Chapter 2

Matter is anything that has a mass and takes up space. Mass—is a measure of the amount of matter the object contains. The properties of matter describe the characteristics and behavior of matter, including the changes that matter undergoes. Describes an object’s action and it’s state and any changes it undergoes. Ex: helium is a gas, it tends to float and explode

Substance—matter that has a uniform and definite composition. Pure Substance—substance that has identical intensive properties because every sample has the same composition. Ex: gold and copper Physical properties—a quality or condition of a substance that can be observed or measured without changing the substance’s composition. Ex: hardness, color, conductivity, and malleability

3 states of matter Solids Liquids Gases

A form of matter that has definite shape and volume. The shape of the solid does not depend on the shape of the container. Key Characteristics Definite shape Definite volume Not easily compressed

A form of matter that has indefinite shape, flows, and has a fixed volume. Key Characteristics Indefinite shape Definite volume Not easily compressed

A form of matter that takes both the shape and volume of its container. Key Characteristics Indefinite shape Indefinite volume Easily compressed

Physical change—when some properties of the material changes, but the composition of the material does not change. 2 categories to classify physical changes Reversible irreversible

Examples of physical changes include: Boiling, Freezing, Evaporating, Melting, Dissolving, And crystallizing

Mixture—physical blend of two or more components. 2 classifications of mixtures Heterogeneous mixture—a mixture in which the composition is not uniform. Ex: chicken noodle soup Homogeneous mixture—a mixture in which the composition is uniform. AKA Solution Phase—any part of a sample with uniform composition and properties. Homogeneous mixture has a single phase. Heterogeneous mixture has multiple phases.

Filtration—process that separates a solid from the liquid in a heterogeneous mixture. Distillation—process that separates one liquid from another. Boil the liquid to produce a vapor that is then condensed to a liquid.

Alloys are solid solutions that contain different metals and sometimes nonmetallic substances.

When you dissolve sugar in water, sugar is the solute—the substance being dissolved. The substance that dissolves the solute, in this case water, is the solvent. When the solvent is water, the solution is called an aqueous solution.

Element—the simplest form of matter that has a unique set of properties. Compound—is a substance that contains two or more elements chemically combined in a fixed proportion. Ex: Carbon, oxygen, and hydrogen combine to form sucrose.

Symbols for elements are based on the Latin names for the elements. System was developed by Swedish Chemist Jons Jacob Berzelius ( ) Each element is represented by one or two-letter chemical symbol. Ex: H—Hydrogen, Au—Gold (table 2.2 pg 52)

Of the known elements, only about 90 occur naturally on Earth. The remainder are synthesized, usually in barely detectable amounts, in high-energy nuclear experiments. Less than half of the 90 naturally occurring elements are abundant enough to play a significant role in the chemistry of everyday stuff.

The periodic table organizes elements in a way that provides a wealth of chemical information—much more than is evident to you now. It shows the chemical symbols for the elements. Their symbols usually correspond to their names in Latin.

A more complete definition is that a compound is a chemical combination of two or more different elements joined together in a fixed proportion with a unique set of chemical and physical properties. More than 10 million compounds are known and the number keeps growing. Some new compounds are discovered and isolated from natural chemical sources such as plants and colonies of bacteria and are synthesized in laboratories for many different uses.

Suspension—is a heterogeneous mixture that separates into layers over time. Colloid—contains some particles that are intermediate in size between the small particles in a solution and the larger particles in a suspension. Colloids do not separate into layers.

Physical property—is any characteristic of a material that can be observed or measured without changing the composition of the substances in the material. Examples of physical properties Viscosity Conductivity Malleability Hardness Melting point Boiling point Density

Viscosity—the tendency of a liquid to keep from flowing; resistance to flowing. Conductivity—a material’s ability to allow heat or electric charges to flow. Malleability—the ability of a solid to be hammered without shattering. Hardness of a substance is determined by seeing which of the materials can scratch the other.

Melting point—temperature at which a substance changes from solid to liquid. Boiling point—temperature at which a substance boils. Density—is the ratio of the mass of a substance to its volume. Used to test the purity of a substance.

Section 2.2 Assessment Reviewing Concepts #1-6

Chemical Properties—is any ability to produce a change in the composition of matter. 2 examples of chemical properties: Flammability Is a material’s ability to burn in the presence of oxygen. Reactivity How readily a substance combines chemically with other substances.

Chemical change—occurs when a substance reacts and forms one or more new substances. 3 common types of evidence for a chemical change: Change in color Production of a gas Formation of a precipitate

Reviewing Content #1-10 Understanding Concepts #11-16