Chemistry Midterm

Chemistry Midterm

Matter: has mass and volume

- Pure Substance: elements and compounds (naturally), has a definite composition

- Mixtures: a combination of 2 or more elements or compounds, when combined do not lose their identities, can be separated by physical means

Heterogenous: mixture that does not have uniform properties (Ex. water and oil)

Homogenous: has uniform properties throughout (Ex. gasoline)

- Element: simplest, most pure type of matter that can not be broken down (if broken down it loses it properties) named after properties, people, places, and latin and greek names

- Atom: basic unit in chemistry, smallest unit in an element

- Molecule: smallest unit in a compound

- Compound: 2 or more elements chemically combined that takes on new properties, only can be separated by chemical means

- Metals: solid at room temp, luster, dense, high melting point, malleable, ductile, tenacious, combined metals called an alloy

- Non-Metal: poor conductors, brittle, many are gases, good insulators,

- Metalloids: semi-metals, good conductors of electricity, poor of heat

Describing Matter

- Quantitative: described with numbers (Ex. temp)

- Qualitative: the nature of something (Ex. color)

- Solid: molecules are tightly packed together, the distance between particles is small, attractive force is small, intermolecular density force is small.

- Liquid: molecules are further apart than solid, attractive forces are weaker, intermolecular forces are greater,

- Gas: molecules are x10 further apart than solid or liquid, greater molecular distance, molecules act independently

- Potential Energy: stored energy

- Kinetic Energy: energy in motion

- Physical Properties: characteristics of a substance that can be determined without changing its composition such as; color, size, mass, shape, state, density, boiling/melting

- Chemical Properties: describes an object's ability to react and form new substances such as; PH, reactivity

- Physical Change: change in physical properties such as size, shape, or change of states without changing its composition

-Chemical Change: occurs when a new substance