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is anything tha has mass and takes up space.


is a single kind of matter that is pure, meaning that it always has a specific makeup -and a specific set of properties

physical property

is a characteristic of a pure substance that can be observed without changing it into another substance.

chemical property

is a characteristic of a pure substance that describes its ability to change in different substances.


is a pure substance that cannot be broken down into any other substances by chemical or physical means.


smallest unit of an element that maintains the properties of that element.

chemical bond

a force of attraction that holds two atoms together


Two or more atoms held together by chemical bonds.


is a pure substance made of two or more elements chemically combined in a set ratio. Ex. NA+CL. one atom to one atom ratio=NACL molecule

chemical formula

A group of symbols and numbers that shows the elements that make up a compound

heterogenous mixture

A mixture with uneven distribution of different substances, solids, liquids, gases.

homogeneous mixture

contains two or more substances that evenly mixed on a molecular level but still are not bonded together


is an example , a homogeneous mixture of two or more substances, a homogeneous mixture of two or more substances

physical change

a change that alters the form or appearance of a material but does not convert the material into new substances

chemical change

A change in which a substance is converted into a substance with different composition and properties

law of conservation of matter

a fundamental principle of classical physics that matter cannot be created or destroyed in an isolated system


is the ability to do work or cause change


is a measure of the average energy motion of particles of matter.

thermal energy

total energy of all particles in an object

endothermic change

change in which energy is taken in

exothermic change

change in which energy is released

chemical energy

form of energy, stored in chemical bonds between atoms.

electromagnetic energy

a form of energy that travels through space as waves.

electrical energy

is the energy of electrically charge particles mving from one place to another.


a material composed of two or more elements or compounds that are physically mixed together but not chemically combined

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