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Science Chapter 2
Term | Definition |
---|---|
Matter | anything that has mass and takes up space |
Chemistry | the study of the properties of matter and how matter changes |
Substance | a single kind of matter that is pure, meaning it always hasa specific makeup-or composition- and a specific set of properties |
element | a pure substance that cannot be broken down into any other substance by chemical or physical means |
atom | the basic particle from which all elements are made |
chemical bond | a force of attraction between two atoms |
molecules | groups of two or more atoms held together by chemical bonds |
compound | a pure substance made of two or more elements chemically combined in a set ratio |
chemical formula | a combination of symbols that represents the elements in a compound and their proportions |
mixture | made of two or more substances- elements, compunds, or both- that are together in the same place but are not chemically combined |
heterogeneous mixtures | when you can see the different parts in a mixture |
homogeneous mixtures | when you can't see the parts in a mixture because they are so evenly mixed |
solution | an example of a homogeneous mixture that doesn't have to be a liquid |
weight | a measure of the force of gravity on you |
mass | the measurement of the amount of matter in an object |
International System of Units | |
volume | the amount of space that matter occupies |
density | the mass of a material in a given volume |
physical change | any change that alter sthe form or appearance of matter but does not make any substance in the matter into a different substance |
chemical change | a change in matter that produces one or more new substances |
law of conservation of mass | the fact that matter is not created or destored in any chemical or physical change |
temperature | a measure of the average energy of random motion of particles of matter |
thermal energy | the total energy of all of the particles in an object |
endothermic change | a change in whicha energy is taken in |
exothermic change | releases energy |
combustion | a chemical cahnge that releases energy in the for of heat and light |