open system
A system in which matter can react to air and leave a container
closed system
A system in which no matter is allowed to enter or leave a container
chemical reaction
Process in which one or more substances are changed into new substances
Law of conservation of mass
All mass/matter/energy present in the beginning of the reaction are present after the reaction. Matter is neither created nor destroyed
reactant
The starting substances that takes part in and undergoes change during a reaction.
product
A substance produced in a chemical reaction
precipitate
Solid compound produced from 2 liquids during a chemical reaction. Sign of a chemical reaction.
bubbles
Gas given off during a chemical reaction; may or may not have an odour. Sign of a chemical reaction.
signs of a chemical reaction
change in temperature, formation of bubbles, precipitate forms, color change, change in smell, difficult to reverse
subscript
Number written after and BELOW an element in a chemical formula telling you how many of the preceding element are needed for that compound or molecule.
chemical equation
Written representation of a chemical reaction/chemical change; shows all the reactants and products. Always in the form of: Reactants arrow Products.
chemical change
Chemical reaction; when substances interact with each other. Original substances are used up.
physical change
When a substance changes its phase (changes to a solid, liquid , gas, or plasma) or is modified (size, shape, etc) but remains the same substance.
compound
Any amount of a chemical combination of 2 or more different atoms.
molecule
A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound