Chemical Changes (Reactions)

Chemical Changes (Reactions)

• Reactants

• Products

• Synthesis

• Single Replacement

• Double Replacement

• Decomposition

Chemical Reactions

• Indicators– Fizzing (gas produced)

– Color change

– Gets cloudy/precipitant (solid produced)

– Heat released or absorbed

– Light emitted

– Odor changes

Chemical Reactionshttp://ed.ted.com/lessons/if-molecules-were-people-george-zaidan-and-charles-morton

• Reactants Products

• H2O2 H2O + O2

–What are the reactants? What are the products?

Chemical Reactions

There are 4 kinds of Chemical Reactions that occur:

Synthesis Decomposition

Single Double Replacement Replacement

Chemical Reactions

• Synthesis

–Two or more reactants are combined to form one product.

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Chemical Reactions

• Decomposition

–One reactant breaks down into two or more products.

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Chemical Reactions

• Single Replacement

–An element and a compound combine.

–One element from the reactants replaces another in the products.

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Chemical Reactions

• Double replacement

–Two compounds combine.

–Two elements in the reactants switch places in the products.

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Chemical Reactions-Practice Identifying

• Example #1

• H2 + O2 H2OWhich is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Example #2

• Li3P Li + P

Which is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Example #3

• Na + MgCl2 Mg + NaCl

Which is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Example #4

• SiCl4 + O2 SiO + Cl2

Which is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Example #5

• C5O3 C + O2

Which is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Example #6

• Rb2O + AlF3 RbF + Al2O3

Which is it?

•Synthesis

•Decomposition

•Single Replacement

•Double Replacement

Chemical Reactions

• Law of conservation of Matter

–Atoms are not created or destroyed

–The number of atoms at the START of a reaction, there must be the same number of atoms AFTER the reaction.

–Equations must be balanced!

Chemical Reactions

• Balancing Chemical Equations STEPS:

–Count the number of atoms for each element in the reactants and in the products.

–Compare the numbers to see if each element is balanced (equal) with itself.

–Use WHOLE NUMBER coefficients to “fix” unbalanced elements.

• Do not change the subscripts!

Chemical Reactions

• Example #1

• H2 + O2 H2O

Chemical Reactions

• Example #2

• Li3P Li + P

Chemical Reactions

• Example #3

• Na + MgCl2 Mg + NaCl

Chemical Reactions

• Example #4

• SiCl4 + O2 SiO + Cl2

Chemical Reactions

• Example #5

• C5O3 C + O2

Chemical Reactions

• Example #6

• Rb2O + AlF3 RbF + Al2O3

Chemical Reactions

• Example #7

SnO2 + H

2 → Sn + H

2O

Chemical Reactions

• Example #8

• Mg(ClO3)2 + Na NaClO3 + Mg

Chemical Reactions

• Example #9

• Al2(SO4)3 + RbF AlF3 + Rb2SO4

Chemical Reactions

• Identify and Balance

• Al + F2 AlF3

Chemical Reactions

• Identify and Balance

• Ca(MnO4)2 + FeCl4 CaCl2 + Fe(MnO4)4

Chemical Reactions

• Identify and Balance

• Si3O Si8 + O2

Chemical Reactions

• Identify and balance

• Cs2O + N2 Cs3N + O2

Warm Up Classify the following chemical reactions as

decomposition, single replacement, double replacement or synthesis:

For the first equation, what are the reactants and what are the products?

Write the chemical formula for Barium Nitride

Acids and Bases

Acids & Bases

• Acids

• Examples: Citric Acids, Gastric Acid, Battery Acid, Sodas, tomatoes, etc.

• Properties: corrosive, produce H+ ions, sour taste, electrolytes, pH range = 0-6.9

• Examples of Formulas: HCl, H2SO4, H3PO4, HNO3, etc

Acids & Bases

• Bases

• Examples: Soaps, Cleaning supplies, Hair Relaxers, etc.

• Properties: corrosive, produce OH- ions, bitter taste, electrolytes, slippery feel, ph range 7.1 to 14

• Examples of Formulas: NaOH, KOH, Mg(OH)2, Al3(OH), NH3, NH4OH

Acids & Bases-pH Scale

Acids and Bases-Compare & Contrast

Acids and Bases--Identify

1. pH =2

2. HF

3. pH= 7

4. RbOH

5. Ca(OH)2

6. pH= 9

7. Sour taste

8. Slippery feel

9. Electrolyte

10.pH = 13

11. pH = 4

12.H2SO4

13.HBr

14.FrOH

15.Corrosive

16.Bitter taste

Acids & Bases

• Neutralization Reactions

• Only an Acid can neutralize a base, and only a Base can neutralize an acid.

• H+ comes off of the Acid and OH- comes off of the Base

• Acid + Base Water + Salt

• HCl + KOH H2O + KCl

Acid/Base Neutralization

• HBr + LiOH _________ + _________

• FrOH + HCl _________ + _________

• H2S + Mg(OH)2 ________ + _______

• ______ + HF H20 + KF

• ______ + CsOH H20 + CsI