Elements And Compounds Middle School

7,325 views
6,968 views

Published on

We used this presentation after students investigated what happened when mixing vinegar and baking soda. Students researched what happened and reported to the class. This was a follow-up to clarify a few points.

Published in: Education, Business, Technology
0 Comments
4 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
7,325
On SlideShare
0
From Embeds
0
Number of Embeds
299
Actions
Shares
0
Downloads
327
Comments
0
Likes
4
Embeds 0
No embeds

No notes for slide

Elements And Compounds Middle School

  1. 1. Elements and Compounds Notes 1/20/10
  2. 2. Atoms are the smallest parts of Elements Everything that exists is made up of different combinations of elements. All of the elements that are known are listed by their properties on the periodic table. The smallest little piece of any element that you can have is called an ATOM. Metals on the left, nonmetals on the right, similar properties
  3. 3. All atoms of an element have the same # of protons The # of protons in the atoms of a substance is what makes it different and unique. That is why it is used as the atomic number to identify an element on the periodic table. Ex: The only difference between Fluorine and Neon is 1 proton.
  4. 4. Atoms like to share electrons This takes energy This bonds them together This creates a new substance called a molecule Some atoms like to pair up with other atoms. Some atoms do this easily (like Na) and others don’t (C). This depends on their reactivity. Other atoms don’t do it at all (noble gases). When they pair up, it has to do with giving each other electrons. When they do that, it creates a CHEMICAL BOND that makes them stick together.
  5. 5. You cannot separate atoms that have been bonded together by physical means (like separating a mixture). In order to separate atoms, or bond them together, or make them rearrange, they have to go through a chemical reaction. It takes energy, sometimes a lot of it, to separate atoms that are sharing electrons.
  6. 6. + Sodium Chlorine Sodium Chloride (Na) (Cl) (NaCl) New Substance = New Properties A chemical reaction is when a chemical change takes place and there are new chemical bonds formed. When this happens, the new compound has totally different physical and chemical properties, because it has been changed (that’s why a change in properties indicates a chemical change).
  7. 7. + Sodium Chloride Sodium Atoms Chlorine Atoms Molecules A chemical reaction is when a chemical change takes place and there are new chemical bonds formed. When this happens, the new compound has totally different physical and chemical properties, because it has been changed (that’s why a change in properties indicates a chemical change).
  8. 8. Molecules are the smallest parts of COMPOUNDS
  9. 9. Gold Au Pure Substances Elements OR compounds have Sugar only one type of C6H12O6 component
  10. 10. That’s what makes them PURE SUBSTANCES Has only one type of component (atom) Mixture Pure Substance
  11. 11. Chemical Reactions... Reactants Yields Products This is an example of how a chemical reaction works. Imagine each person is a type of atom. They break up with whatever partner they are bonded with and reorganize with new partners. Are there the same total number of people (atoms) at the beginning and the end? YES They have just changed places. This is how the conservation of mass is. You aren’t destroying anything during a chemical reaction, you are just changing the properties of the substances by arranging the atoms differently.
  12. 12. Chemical Reactions... ENERGY ADDED ENERGY RELEASE Start with End with 3 total people 3 total people (3 atoms) (3 atoms) This is an example of how a chemical reaction (change) works. Imagine each person is a type of atom. They break up with whatever partner they are bonded with and reorganize with new partners. Are there the same total # of people (atoms) at the beginning and at the end? YES They have just changed places. This is how the conservation of mass is. You aren’t destroying anything during a chemical reaction, you are just changing the properties of the substances by arranging the atoms differently.
  13. 13. Chemical Reactions... ENERGY ADDED ENERGY RELEASE It takes energy to start a chemical reaction, because it requires energy to break bonds (you are doing work on the bonds). When the bonds reform to make new substances, it releases chemical energy stored in the compounds. If it absorbs more energy than it releases, the temperature drops because it is using more energy than it is releasing (endothermic) If breaking the bonds doesn’t require much energy, but it releases more, then the temperature raises (exothermic)
  14. 14. Think back... How does what we have talked about relate to the chemical reaction you researched?
  15. 15. Vinegar + Baking Soda What elements make up the molecules of vinegar and baking soda? How were the water, carbon dioxide, and sodium acetate made? How many reactants and products did you have? Was this reaction endothermic or exothermic? When the new substances were made, did it create or destroy the matter? WHAT FACTORS DO YOU THINK COULD EFFECT HOW FAST THE CHEMICAL REACTION TOOK PLACE?

×