WRITE

Return to page 7 of you science notebook. Think about the Law of Conservation of Mass. In your own words, write down the meaning of the Law of Conservation of Mass. Here is my notebook to help you (Make sure you go to page 5 inside the notebook, NOT slide 5):

If you have trouble viewing the slides above, use this link: Mrs. Flores's Notebook

THINK

In the Phet Reactants, Products and Leftovers Simulation, you made "Sandwiches" and used a chemical formula:

BUT THE SANDWICH MODEL WAS NOT A PERFECT EXAMPLE OF WHAT HAPPENS IN CHEMISTRY. LET US READ ABOUT THE DIFFERENCES.

1) In the simulation, if you needed two atoms of cheese to make a sandwich, you still have a cheese sandwich. In real chemistry, one atom changes everything and in a much grander way. In chemistry, each atom (bread or cheese) makes a bigger difference than just adding a slice of cheese. For example, you breath a very important molecule called the oxygen molecule and you cannot breath in a molecule of carbon dioxide. The only difference between an oxygen molecule and a carbon dioxide molecule is ONE ATOM of carbon. In addition, if you take away an oxygen from carbon dioxide and you have a poison called carbon monoxide. Here are models of each of these real life molecules.

2) Another difference between the sandwich model and chemistry is that molecules can be quite larger than the ones you saw. Here is a molecule of STARCH, which is one of many molecules found in bread.

Starch is a very large molecule made from many sugar molecules.

COMPLETE

Go to the Phet Simulation and play the "Game" (as explained in your W4.1 worksheet). You will select a number of molecules needed for a chemical reaction to follow the Law of Conservations of Mass. Remember the Law of Conservation of Mass states that all the atoms in the reactant must also be seen in the produce because atoms do not disappear, they just change position or move to make different molecules. Make sure you try to complete all 3 levels.