Physical Science B Unit 4

chemical reaction

a process where substances change to form new substances

reactant

a substance you start with in a chemical reaction

product

a substance that is formed in a chemical reaction

chemical equation

a way to show a chemical reaction using symbols and formulas

arrow

a symbol (→) that means “yields” or “produces”

coefficient

a number placed in front of a formula to show how many molecules are present

subscript

a small number that shows how many atoms are in a molecule

atom

the smallest unit of matter that makes up elements

molecule

a group of atoms bonded together

element

a pure substance made of only one type of atom

compound

a substance made of two or more different atoms chemically combined

law of conservation of matter

the rule that matter cannot be created or destroyed

mass

the amount of matter in an object

balanced equation

a chemical equation with the same number of each type of atom on both sides

unbalanced equation

a chemical equation that does not have equal atoms on both sides

conservation

the idea that something stays the same and is not lost

rearrange

to change the order or position of atoms

model

a drawing or object used to show how something works

synthesis reaction

a reaction where two or more substances combine to form one product

decomposition reaction

a reaction where one substance breaks apart into two or more products

replacement reaction

a reaction where atoms swap places