1. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations?

2. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formulas Are written using an element’s chemical symbol from the periodic table Used to identify how many atoms of each element are present

3. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water H20H20 Subscript Indicates the number of atoms of the element to the left. If there is no number, there is only 1 atom. 2 Hydrogen atoms 1 Oxygen atom

4. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water 3H20 3H20 Coefficient Indicates how many molecules are present 3 molecules of water

5. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water 3H20 3H20 Coefficient The coefficient multiplied by the subscript is the number of atoms per element. 6 atoms of hydrogen 3 atoms of oxygen

6. Matter is neither lost or gained during a chemical reaction. It is rearranged. 2H 2 + O 2  2H 2 O +  The chemical equation is balanced. O OH H H H O HH O HH Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? The Law of Conservation of Mass

7. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? How to calculate if a chemical equation is balanced. 2H 2 + O 2  2H 2 O 1.) Take an element inventory for each side of the equation. 2.) Calculate the number of atoms for each element. 3.) If the numbers match, then it is balanced. ReactantsProducts H - 4 O - 2

8. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Synthesis or Combination Reactions A reaction where two or more reactants (elements or compounds) react to form only a single product. Examples of this type of reaction: metal + oxygen  metal oxide 4 Na + O 2  2 Na 2 O nonmetal + oxygen  nonmetal oxide C + O 2  CO 2

9. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Decomposition Reactions A reaction where a single compound undergoes a reaction to form two or more products. Some examples: 2 H 2 O + direct electric current  2 H 2 + O 2 C 12 H 22 O 11 sugar + heat  12 C + 11 H 2 O Caramelized sugar is brown due to the carbon that is present. 2 NaHCO 3 + heat  Na 2 CO 3 + CO 2 + H 2 O Sodium bicarbonate can be used to extinguish fires because the heat from the fire liberates CO 2 which then smothers the flames. This is not an oxidation-reduction reaction.

10. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Single Replacement Reaction A reaction where one element reacts with a compound and replaces another element in that compound. An example of this type of reaction is... Fe + CuSO 4  FeSO 4 + Cu If you immerse an iron nail in a copper sulfate solution, it will come out coated with copper metal.

11. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Double Replacement Reaction A reaction where two positive ions exchange partners. Usually involve the formation of a precipitate(the most common examples) or a gas as one of the products. Examples of this type of reaction include the following... AgNO 3 + NaCl  AgCl  + NaNO 3 CaCO 3 + 2 HBr  CaBr 2 + CO 2  + H 2 O The arrow pointing down means that a precipitate is formed. The arrow pointing up means that a gas is formed.

12. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Combustion Reactions Always involve molecular oxygen O 2. Anytime anything burns (in the usual sense), it is a combustion reaction. Combustion reactions are almost always exothermic (i.e., they give off heat). For example when wood burns, it must do so in the presence of O2 and a lot of heat is produced:

13. Now take some time… Take 2 minutes to go over your notes and highlight or underline the main ideas that answer the essential question, you should not highlight everything: Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations?

14. Time to use the left hand column You will be writing your own questions from now on! To get you started, verbs will be provided

15. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formulas Are written using an elements chemical symbol from the periodic table Used to identify how many atoms of each element are present Choose one verb to write your question: Define Describe Compare Explain

16. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water H 2 0 Subscript- tells you how many atoms per element there are There are 2 Hydrogen atoms and 1 Oxygen atom in water Choose one verb to write your question: Define Describe Compare Explain

17. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water 3H 2 0 Coefficient- tells you how many molecules there are There are 3 molecules of water Choose one verb to write your question: Define Describe Compare Explain

18. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Chemical formula for water 3H 2 0 Coefficient- you multiply the coefficient by the subscript to get the number of atoms per element There are 6 hydrogen atoms and 3 oxygen atoms Choose one verb to write your question: Define Describe Compare Explain

19. During a chemical reaction, no matter is created or destroyed, it is just rearranged 2H 2 + O 2  2H 2 O +  The chemical equation is balanced H H O O H H O O HHHH Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? Law of conservation of mass Choose one verb to write your question: Define Describe Compare Explain

20. Topic: Chemical Formulas Essential Question: What is the law of conservation of mass, and how does it apply to chemical equations? How to see if a chemical equation is balanced 2H 2 + O 2  2H 2 O 1.) Take an element inventory for each side of the equation 2.) Write down the number of atoms for each element 3.) If the numbers match, then it is balanced H - O- 4 22 4 Choose one verb to write your question: Define Describe Compare Explain

21. Time to use the left hand column You will now write questions on your own using question starters that are provided

22. Now let’s write a summary Look at each question you wrote on your own, and answer each question in a complete sentence.