1. Chemical Equations and Reactions
Chapter 8
Modern Chemistry

2. Do Now Each week should be on a new page
The # of the week should be at the top of the page
Each day of the week should be in the margin

3. Do Now
Week 18
Monday
Tuesday
Wednesday
Thursday
Friday

4. Do Now Complete the following chemical equations. Aluminum + Bromine
Sodium + Oxygen
Magnesium + Iodine
AlBr3
Na2O
MgI2

5. Standards
HS-PS1-7:
Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction

6. What are the indications that a chemical reaction has taken place?
Essential Question
What are the indications that a chemical reaction has taken place?

7. Vocabulary Chemical Reaction Chemical Equation Precipitate
The process by which one ore more substances are changed into one or more different substances
Represents, with symbols and formulas, the identities and relative molecular or molar amounts of the reactants and products in a chemical reaction
A solid that is produced as a result of a chemical reaction in solution and that separates from the solution.

8. Chemical Reaction/Equation
Use your periodic table to combine two elements to create a chemical reaction. Remember to balance your charges. Be able to explain your reaction.

9. Precipitate

10. Indications of a Chemical Reaction
Evolution of heat and light together; heat or light is not always a sign of a chemical change.
What types of common chemical reactions can you think of that creates both light and heat?

11. Indication of a Chemical Reaction
Production of a gas; usually indicated by the release of gas bubbles. Example carbon dioxide being released when baking soda is mixed with vinegar
What types of common chemical reactions can you think of that creates gas bubbles?

12. Indication of a Chemical Reaction
Formation of a precipitate, if a solid appears when two solutions are mixed; this is evidence of a chemical reaction.
Silver chromate and Potassium chromate

13. Color Change
Color change; any change of color is usually an indication of a chemical reaction
What types of common chemical reactions can you think of that creates a color change?

14. This is due at the end of the class
Practice
Write one paragraph to explain the indications of a chemical reaction. Give an example for each indication.
This is due at the end of the class

15. Do Now
Write 2-3 sentences to explain the difference between a chemical reaction and a chemical equation?

16. Characteristics of Chemical Equations
A properly written chemical equation must contain:
Known facts – Correct element symbols, information from a verified source (periodic table)
Correct formulas for the reactants and products (use charges to create the correct formulas. Remember the 7 diatomic molecules
The law of conservation of mass must be satisfied – All chemical equations must be balanced.
Hydrogen H2
Nitrogen N2
Oxygen O2
Fluorine F2
Chlorine
Cl2
Bromine
Br2
Iodine I2
Exceptions are S8, and P4

17. Writing Word and Formula Equations
A word equation is an equation in which the reactants and products are represented by words.
It has only qualitative meaning, no quantities of reactants or products are given.
Provide valuable information needed to write and balance a formula equation.
Example
methane + oxygen →carbon dioxide and water

18. Writing Word and Formula Equations
A formula equation is an equation in which the reactants and products are represented by symbols and formulas.
It has only qualitative meaning, until the equation is balanced are given.
Provide valuable information such as the number of moles or atoms of the elements or formulas contained in the equation.
Example
methane + oxygen →carbon dioxide and water
CH4(g) O2(g) → CO2(g) + H2O(g) Unbalanced
CH4(g) O2(g) → CO2(g) + 2H2O(g) balanced

19. Symbols Used in Chemical Equations
List can be found on page 266 of your textbook.

20. Practice
Write word and balanced chemical equations for the following reaction. Include symbols for physical states when indicated.
Hydrogen peroxide in an aqueous solution decomposes to produces oxygen and water.

21. Practice
Write word and balanced chemical equations for the following reaction. Include symbols for physical states when indicated.
Solid Copper metal reacts with aqueous silver nitrate to produce solid silver metal and aqueous copper nitrate.

22. Practice
Write word and balanced chemical equations for the following reaction. Include symbols for physical states when indicated.
Solid zinc metal reacts with aqueous copper sulfate to produce solid copper metal and aqueous zinc sulfate

23. Explain why all equations need to be balanced.
Exit Ticket
Explain why all equations need to be balanced.

24. Do Now
Describe a diatomic molecule. List the seven diatomic molecules that appear on the periodic table.
What other two elements on the periodic table cannot exist on their own.

25. Do Now
Write the word and formula equation for the chemical reaction that occurs when solid sodium oxide is added to water at room temperature and forms sodium hydroxide(dissolved in water). Try to balance the equation.

26. Balancing Chemical Equations
Essential Question
What are the step necessary to balance a chemical equation?

27. How to Balance an Equation
Balance the different types of atoms one at a time
First balance the atoms of elements that are combined and that appear only once on each side of the equation. (start with the largest compound first)
Balance polyatomic ions that appear on both sides of the equation as single units
Balance H atoms and O atoms after atoms of all other elements have been balanced.

28. Practice
Write word and balanced equations for the following. Remember to add symbols for physical states when indicated.
Use whiteboards.

29. Practice 1
Nitrogen dioxide gas reacts with water to form aqueous nitric acid and nitrogen monoxide gas. (the formula for nitric acid is HNO3

30. Practice 2
Solid potassium chlorate decomposes to form solid potassium chloride and oxygen gas.

31. Practice
Turn to page 274 in your textbooks, complete practice problems 1, a,b, and c

32. Do Now Write and balance the formula from the word equations below.
When chlorine gas reacts with methane(CH4), carbon tetrachloride and hydrogen chloride are produced.
When sodium oxide is added to water, sodium hydroxide is produced.
3. In a blast furnace, iron (III) oxide and carbon monoxide gas produce carbon dioxide gas and iron.

33. Do Now Balance the following equations
NaOH →Na2O + H2O
Fe + O2 →Fe2O3
CO2 + H2O →C6H12O6 + O2
FeS + HCl →FeCl2 + H2S
O2 + H2 →H2O
Cl2 + NaI →NaCl + I2
Al(NO3)3 + H2SO4 →Al2(SO4)3 + HNO3

34. Check Your Answers 2 NaOH →Na2O + H2O 4 Fe + 3O2 →2 Fe2O3
6 CO2 + 6 H2O →C6H12O6 + 6 O2
FeS + 2 HCl →FeCl2 + H2S
O2 + 2 H2 →2 H2O
Cl2 + 2 NaI →2 NaCl + I2
2 Al(NO3)3 + 3 H2SO4 →Al2(SO4)3 + 6 HNO3

35. Types of Reactions You need to be able to identify each type.
Synthesis reactions
Decomposition reactions
Single displacement reactions
Double displacement reactions
Combustion reactions
Neutralization reactions
You need to be able to identify each type.

36. 1. Synthesis General: A + B → AB Example C + O2 → +
A composition reaction produces a single substance from multiple reactants.

37. Ex. Synthesis Reaction

38. Practice 2 2 NaCl(s) MgF2(s) 2 AlF3(s) 2 3 Now, balance them.
Predict the products.
Na(s) + Cl2(g) →
Mg(s) + F2(g) →
Al(s) + F2(g) → 2 2
NaCl(s)
MgF2(s) 2
AlF3(s) 2 3
Now, balance them.

39. Synthesis Reactions With Oxides
Oxides of active metals react with water to produce metal hydroxides.
CaO(s) + H2O(l) →Ca(OH)2 (S)
What are some other metals that may react with water to produce metal hydroxides?
Many oxides of nonmetals react with water to produce oxyacids.
SO2(g) + H2O(l)→ H2SO3

40. 2. Decomposition General: AB → A + B Example: NaCl → +
A decomposition reactionproduces multiple products from a single reactant

41. Decomposition Reaction
There are many types of decomposition reactions. Decomposition reactions are the opposite of synthesis reactions.
Five types of decomposition reactions are:-
1. Decomposition of binary compounds
2. decomposition of Metal Carbonates
3. Decomposition of Metal Hydroxides
4. Decomposition of Metal chlorates
5. Decomposition of Acids

42. Ex. Decomposition Reaction

43. Decomposition of Binary Compounds
Simplest kind of decomposition reaction
Decomposed with heat or electricity (electrolysis)
Less active metal oxides decompose with heat
Decomposes into its elements

44. Practice Remember: Compound will be decomposed into its elements
HgO --->
H2O --->
MgCl2 --->
FeS --->

45. Decomposition of Metal Carbonates
Decomposes to produce a metal oxide and carbon dioxide gas.
Practice
CaCO3 --->
Na2CO3 --->

46. Decomposition of Metal Hydroxides
All except for group 1 metals
Decompose when heated to yield metal oxides and water.
Practice
Ca(OH)2 --->
NaOH --->

47. Decomposition of Metal Chlorates
When heated, metal chlorates decompose to form a metal chloride and oxygen.
Practice
KClO3 --->
Ba(ClO3)2 --->

48. Decomposition of Acids
Some acids decompose into nonmetal oxides and water.
Practice
H2CO3 →
H2SO4→

49. More Practice 1.ZnCO3 →__________ 2. Ba(ClO3)2 →_______
3. Sb2O5→___________
4. CaCO3→__________
5. KClO3→___________
6. H2CO3 →__________
7. Ba(OH)2 →________
8. HgO →___________
9. NaCl →___________
10. H2SO4→_________

50. Describe a decomposition reaction
Exit ticket
Describe a decomposition reaction

51. 3. Single Displacement General: AB + C → AC + B Example: Zn + CuCl2 →

52. Single Displacement Also known as replacement reactions
One element replaces a similar element in a compound
Commonly occurring in aqueous solutions

53. Practice
l. Ag KNO >
2. Zn AgNO >

54. Practice 3. Al + H2SO4 -----> 4. Cl2 + KI ----->
5. Li H2O >

55. More Practice 5. Li + H2O -----> 6. Cu + FeSO4 ----->
7. Na H2O >
8. Fe Pb(NO3) >
9. Cu H2O >
10. Cu Al2(SO4) >

56. Single Displacement/Rule Exceptions
Displacement of hydrogen in water by a metal
Produces metal hydroxides and hydrogen
Ex.
Na(s) + H2O(l) → 2
Na(s) H2O(l) → NaOH(aq) + H2(g) 2 2

57. Single Displacement/ Rule Exceptions
Displacement of Halogens
Displacement depends on the position of the halogen in the group
Each element can replace any element below it, but not any element above it.
Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(l)
Br2(l) + KCl(aq) → no reaction

58. Exit Ticket
In a single replacement reaction, one ___________________ replaces a _______________ element in a compound.
Cl NaI-----→

59. Ex. Single Replacement Reaction

61. Single Replacement Reactions
Write and balance the following single replacement reaction equation:
Zn(s) HCl(aq) → ZnCl2 + H2(g) 2
NaCl(s) + F2(g) → NaF(s) + Cl2(g)
Al(s)+ Cu(NO3)2(aq)→ 2 2 2 3 3
Cu(s)+ Al(NO3)3(aq) 2

62. 4. Double displacement General: AB + CD → AD + CB Example: MgO + CaS →

63. Double Displacement
Ions of two compounds exchange places in an aqueous solution to form two new compounds.
Compounds formed are usually precipitates, gas or molecular compounds

64. Double Replacement Reactions
Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together
Example:
AgNO3(aq) + NaCl(s) → AgCl(s) + NaNO3(aq)
Another example:
K2SO4(aq) + Ba(NO3)2(aq) → KNO3(aq) + BaSO4(s) 2

65. Practice Predict the products. HCl(aq) + AgNO3(aq) →
CaCl2(aq) + Na3PO4(aq) →
Pb(NO3)2(aq) + BaCl2(aq) →
FeCl3(aq) + NaOH(aq) →
H2SO4(aq) + NaOH(aq) →
KOH(aq) + CuSO4(aq) →

66. 5. Combustion Reactions
Combustion reactions - a hydrocarbon reacts with oxygen gas to release large amounts of energy in the form of heat and light
This is also called burning!!!

67. Combustion Reactions In general: CxHy + O2 → CO2 + H2O
Products are ALWAYS
carbon dioxide and water. (although incomplete burning does cause some by-products like carbon monoxide)
Combustion is used to heat homes and run automobiles (octane, as in gasoline, is C8H18)

68. Combustion
Example
C5H O2 → CO2 + H2O
Write the products and balance the following combustion reaction:
C10H O2 → 8 5 6

69. Practice 1. methane (CH4) + oxygen 2. ethane (C2H6) + oxygen
3. propane (C3H8) oxygen
4. butane (C4H10) oxygen
5. pentane (C5H12) oxygen
6. hexane (C6H14) oxygen
7. ethene (C2H4) oxygen
8. ethyne (C2H2) oxygen

70. Mixed Practice State the type & predict the products. BaCl2 + H2SO4 →
C6H12 + O2 →
Zn + CuSO4 →
Cs + Br2 →
FeCO3 →

71. List and describe the five types of chemical reactions.
Exit Ticket
List and describe the five types of chemical reactions.