Law of Conservation of Mass - Lesson 7.2.1

​chemical - a substance with a specific composition
equation - math statement that shows two sides are equal


A model of a chemical reaction that uses element symbols to show what happens.

Chemical Equation

​Law - a sta2tement about a phenomenon that implies a cause and effect between observed objects. Many times it is mathematical like: E=mc

conservation - conserve - save or prevent
Mass - amount of matter in an object

A scientific principle stating that mass cannot be created or destroyed.

Law of Conservation of Mass

​Notebook
Page 146

A chemical change occurs and creates a new substance.

During the chemical reaction, the atoms get rearranged to form something new.

​It can happen anywhere!
Even your stomach.

A scientific Law is:

- something in nature that scientists notice

- it always seems to be true

- it is supported by lots of observations

​

​Remember....

​Matter cannot be created or destroyed.

​The amount of matter in a system stays constant during a chemical change.
See formation of water below!

​Notice that there is 2g of H and 16g of O that forms 18g of water.
2 + 16 = 18

C₄H₈O₂

​How many?
Carbon =
Hydrogen =
Oxygen =

​Let's Review Formulas

NO₂






Al₂(SO₄)₃

​Formulas

​How Many?
Nitrogen =
Oxygen =



How many?
Aluminum =
Sulfur =
Oxygen =

​The arrow is like the equal sign in a math equation.

There are Carbon, Oxygen, and Hydrogen atoms on BOTH sides of the arrow.

They are remixed to form new compounds but there are no new elements added.

​This supports the Law of Conservation of Mass!

​See you Monday for Chemical Equations!