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anything that has mass and takes up space


matter with a composition that is always the same


a substance containing atoms of two or more different elements chemically bonded together


matter that can vary in composition

Heterogeneous Mixture

a mixture in which substances are not evenly mixed

Homogeneous Mixture

a mixture in which two or more substances are evenly mixed but not bonded together


to form a solution by mixing evenly

Physical Property

a characteristic of matter that you can observe or measure without changing the identity of the matter


the amount of matter in an object


the mass per unit volume of a substance


the maximum amount of solute that can dissolve in a given amount of solvent at a given temperature and pressure

Physical Change

a change in the size, shape, form, or state of matter that does not change the matter's identity

Chemical Property

the ability or inability of a substance to combine with or change into one or more new substances

Chemical Change

a change in matter in which the substances that make up the matter change into other substances with different chemical and physical properties


the amount of a particular solute in a given amount of solution


matter that has a definite shape and a definite volume


matter with a definite volume but no definite shape


matter that has no definite volume and no definite shape


a measurement of a liquid's resistence to flow

Surface Tension

the uneven forces acting on the particles on the surface of a liquid


the gas state of a substance that is normally a solid or a liquid at room temperature

Kinetic Energy

energy due to motion


the measure of the average kinetic energy of the particles in a material

Thermal Energy

the sum of the kinetic energy and the potential energy of the particles that make up an object


the change in state from a liquid to a gas


the process of a liquid changing to a gas at the surface of the liquid


the change of state from a gas to a liquid


the process of changing directly from a solid to a gas


the process of changing directly from a gas to a solid

Kinetic Molecular Theory

an explanation of how particles in matter behave


the amount of force per unit area applied to an object's surface

Boyle's Law

the law that pressure of a gas increases if the volume decreases and pressure of a gas decreases if the volume increases, when temperature is constant

Charles's Law

the law that volume of a gas increases with increasing temperature, if the pressure is constant


a small particle that is the building block of matter; the smallest piece of an element that still represents that element


a negatively charged particle that occupies the space in an atom outside the nucleus


positively charged particle in the nucleus of an atom


a neutral particle in the nucleus of an atom

Electron Cloud

the region surrounding an atom's nucleus where one or more electrons are most likely to be found


the region in the center of an atom where most of an atom's mass and positive charge are concentrated

Atomic Number

the number of protons in an atom of an element


atoms of the same element that have different numbers of neutrons

Mass Number

the sum of the number of protons and neutrons in an atom

Average Atomic Mass

the average mass of the element's isotopes, weighted according to the abundance of each isotope


any element that spontaneously emits radiation

Nuclear Decay

a process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation


an atom that is no longer neutral because it has lost or gained valence electrons

Periodic Table

a chart of the elements into rows and columns according to their physical and chemical properties


a column on the periodic table


a row on the periodic table


an element that is generally shiny, is easily pulled into wires or hammered into thin sheets, and is a good conductor of electricity and thermal energy


the ability of a substance to reflect or absorb light at its surface


the ability of a substance to be pulled into thin wires


the ability of a substance to transfer heat or electricity


the ability of a substance to be hammered or rolled into sheets

Alkali Metal

an element in group 1 on the periodic table

Alkaline Earth Metal

an element in group 2 on the periodic table

Transition Element/Transition Metal

an element in groups 3-12 on the periodic table


a element that has no metallic properties


an element in group 17 on the periodic table

Noble Gas

an element in group 18 on the periodic table


an element that has physical and chemical properties of both metals and nonmetals


a substance that conducts electricity at high temperatures but not at low temperatures

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