AP Chem - Ch 1 Vocab

chemistry

the study of the composition, structure, properties, and changes of matter

matter

anything that has mass and occupies space

element

a substance that can not be broken down into simpler substances and is distinguished by its number of protons (or atomic number)

atom

the basic unit of an element, the building blocks of matter

property

a characteristic that gives a sample of matter its unique identity

molecule

a substance composed of 2 or more nonmetals attached to one another in a specific way

states of matter

solid, liquid, or gas

gas (or vapor)

no fixed volume and takes the shape of its container

liquid

a substance that is free flowing, taking the shape of its container, and has a fixed volume

solid

has a definite shape and volume

pure substance

matter that always has the same composition, can only be an element or compound

compound

a substance containing 2 or more elements chemically combined

mixture

a combination of two or more substances that are not chemically combined

homogeneous mixture (solution)

the composition of the components that are uniform throughout

heterogeneous mixture

the different components are not evenly distributed

physical property

can be observed without changing the identity and composition of the substance

chemical property

describes the way a substance may change or react to form other substances

physical change

a substance changes its appearance but not its composition

chemical change (reaction)

a substance transforms into a chemically different substance

SI units

choice of metric units for use in scientific measurements

mass

a measure of the amount of material

volume

the amount of space an object occupies

density

the amount of mass in a unit volume

conversion factor

a fraction whose numerator and denominator are the same quantity expressed in different units