Unit 1 – Beginning and Essential Ideas

accuracy

how closely a measurement aligns with a correct value

atom

smallest particle of an element that can enter into a chemical combination

compound

pure substance that can be decomposed into two or more elements

density

ratio of mass to volume for a substance or object D=m/v

element

substance that is composed of a single type of atom; a substance that cannot be decomposed by a chemical change

extensive property

property of a substance that depends on the amount of the substance

Examples include mass, volume, internal energy, and entropy

heterogeneous mixture

mixture not visibly a seamlessly

ex. smoke, salads,

homogeneous mixture

(also, solution) combination of substances with a composition that is uniform throughout

mixture that visibly seamlessly goes together

intensive property

property of a substance that is independent of the amount of the substance

Examples include temperature, density, and color. 

macroscopic domain

realm of everyday things that are large enough to sense directly by human sight and touch

microscopic domain

realm of things that are much too small to be sensed directly

molecule

bonded collection of two or more atoms of the same or different elements

precision

how closely a measurement matches the same measurement when repeated

pure substance homogeneous substance that has a constant composition