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Chemical Reactions and Equations

Physical and Chemical Changes & Law of Conservation of Mass
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Chemical formula
chemical symbols that indicate the number of atoms of each of the elements found in a compound
Chemical reaction
a process in which atoms of the same or different elements rearrange themselves to form a new substance - some clues that one is taking place or has taken place may include bubbles, smoke, a strong smell, color change, temperature change, or a sizzling sound
Closed system
a physical system that is not open and does not interact with other systems it cannot exchange matter or energy with its surroundings
Coefficient
a number used to multiply a variable
Law of conservation of mass
a law that states that during a chemical reaction matter cannot be created or destroyed it just changes form
Open system
a physical system that is open and does interact with other systems - it does exchange matter or energy with its surroundings
Product
a substance that is formed as a result of a chemical reaction
Reactant
the substances that are present before a chemical reaction occurs - they are altered during the chemical reaction and create new products
Subscript
in a chemical formula, the number written next to the right and slightly below a letter or number - it indicates the number of atoms of the element that are in the molecule