1. Chapter 11 Section 1
Chemistry
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2. Essential Questions
What are the parts of a chemical equation? How can you tell if an equation is balanced? Why does an equation need to be balanced? How do you balance a chemical equation?
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3. Chemical Reactions
New substances are formed by bonds breaking and new bonds being formed
Rearrangement of atoms
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4. Why do reactions occur? Reactions occur to reach a more stable state.
Gain a full set of valence electrons
Reach a more stable energy level
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5. Chemical Equations Representation of a chemical reaction
Iron + Oxygen → Rust
Reactants Products
2 types
Word equations
Formula equations
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6. - Page 321
Products
Reactants

7. Word Equations List the names of reactants and products
Reactants on the left and products on the right
Ex: Iron metal + oxygen gas → iron III oxide
NOTE:
+ means “reacts with”
→ means “produces”, “forms”, “yields” etc.
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8. Formula Equations
Use chemical formulas to represent reactants and products
Example:
Fe (s) + O2 (g)→ Fe2O3 (s)
Letter in parenthesis indicates state
(s) solid
(l) liquid
(g) gas
(aq) aqueous solution (dissolved in water)
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9. Law of Conservation of Mass (conservation of Matter)
Mass cannot be created or destroyed; can only change forms
All chemical reactions and equations MUST obey this law
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10. Chemical Equations
The number of atoms of products and reactants must be equal to one another to follow the law of conservation of mass
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11. Identifying Compounds
Each new element is identified by a capital letter
Example: H2SO4
The elements in Sulfuric Acid
Hydrogen
Sulfur
Oxygen

12. Subscripts C12H22O11 There are 12 atoms of Carbon
There are 22 atoms of Hydrogen
There are 11 atoms of Oxygen
If there is not a subscript listed, it is understood to be 1.
Example: NaCl
There is one atom of Sodium
There is one atom of Chlorine

13. NaHCO3 HCl Hydrogen – 1 Chlorine - 1 Sodium – 1 Hydrogen – 1
You Practice!
NaHCO3
Sodium – 1
Hydrogen – 1
Carbon – 1
Oxygen -3
HCl
Hydrogen – 1
Chlorine - 1

14. There are times you will see a compound with parenthesis
There are times you will see a compound with parenthesis. Pb(NO3)2 The 2 after the parenthesis indicates there are two sets of the parenthesis. Pb(NO3) (NO3) So, in counting the atoms, you would have the following: Lead – 1 Oxygen - 6 Nitrogen -2

15. (NH4)3PO4 Mg(OH)2 You Practice!! Nitrogen – 3 Magnesium – 1
Hydrogen – 12
Phosphorus – 1
Oxygen – 4
Mg(OH)2
Magnesium – 1
Oxygen – 2
Hydrogen – 2

16. Coefficient
2H2SO4 This means there are 2 compounds of Sulfuric Acid. Think: H2SO4 H2SO4 Counting the atoms: Hydrogen – 4 Sulfur – 2 Oxygen - 8

17. 3H3PO4 2H2O You Practice!! Hydrogen – 9 Hydrogen – 4 Phosphorus – 3
Oxygen - 12
2H2O
Hydrogen – 4
Oxygen - 2

18. Counting Atoms Worksheet
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19. Identifying Balanced Chemical Equations
Identify if the following equations are balanced. Check to see if there are an equal number of each atom on both sides.
H2 + O2 → H2O2
MgS + HCl → H2S + MgCl2
NaHCO3 + H2SO4 → Na2SO4 + CO2 + H2O
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20. Identifying Balanced Equations cont.
CH4 + 2 O2 → CO2 + 2 H2O
MgO + H2O → Mg(OH)2
H2SO4 + Fe(OH)3 → Fe2(SO4)3 + H2O
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21. Balancing Rules Write equation with Correct symbols and formulas.
Count the number of atoms of EACH type of element on each side of the arrow to see if it is balanced.
If unbalanced then balance atoms (one at a time) using coefficients (NEVER change the subscripts of a formula, or insert numbers within a formula)
Check work by recounting atoms of each element to make sure the sides are equal. Coefficients should be the lowest possible ratio.
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22. Tips for Balancing
BrINClHOF – gases that are diatomic or that naturally come in pairs Leave single elements until the end to balance If water is involved balance H and O at the end Polyatomic ions can be count like an element when on both sides Always double check your answer
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23. Sample Problem (Not Balanced)
Zn + HCl 2
ZnCl2 + H2
(Not Balanced)
Adjust the coefficients NOT the subscripts.
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24. Practice Problems
Zn(C2H3O2)2 + HBr → ZnBr2 + HC2H3O2 Na2O + H2O → NaOH
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25. Na2SO4 + KCl → NaCl + K2SO4 Ca3(PO4)2 + AgNO3 → Ca(NO3)2 + Ag3PO4
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26. Practice Problems
Magnesium metal plus oxygen gas produces solid magnesium oxide Copper (II) sulfate solid and aluminum metal yield solid aluminum sulfate and copper metal Dicarbon tetrahydride gas reacts with oxygen gas to produce carbon dioxide gas and water vapor
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27. Practice problems
Gold (III) chromate reacted with rubidium phosphate to produce rubidium chromate and gold (III) phosphate Calcium hydroxide reacted with nickel (II) sulfate to produce calcium sulfate and nickel (II) hydroxide
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28. Essential Questions
What are the parts of a chemical equation? How can you tell if an equation is balanced? Why does an equation need to be balanced? How do you balance a chemical equation?
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29. Chapter 11 Section 2
Chemistry
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30. Essential Questions
What are the 5 types of chemical reactions? How can you tell which type of reaction is taking place? How can you predict the products of chemical reactions?
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31. Types of Chemical Reactions
5 Major types of reactions:
Combination/synthesis
Decomposition
Single replacement
Double replacement
Combustion
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32. Combination Reactions
Combination reaction: two or more reactants combine together to yield one product
A + X → AX
A and X could be compounds or elements
AX is a compound
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33. Synthesis Reactions (cont)
Metals and nonmetals react to form ionic solids
2 Na + Cl2 → 2 NaCl
4 Li + O2 → 2Li2O
Metal oxides produce metal hydroxides
CaO + H2O → Ca(OH)2
Nonmetal oxides produce oxyacides
SO3 + H2O → H2SO4
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34. Synthesis Practice Problems
Predict the products of the following reactions. Ba + O2 → Mg + Cl2 → CO2 + H2O → BeO + H2O →
BaO
MgCl2
H2CO3
Be(OH)2
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35. Decomposition Reactions
Decomposition reactions: single reactant breaks down into parts
AX → A + X
A and X could be either elements or compounds
Requires usually heat or catalysis +
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36. Decomposition Reactions (cont)
Binary compounds break into the two elements
2 H2O → 2 H2 + O2 (with electricity)
All metals, except Group 1, yield metal oxides and water when heated
M(OH)x → MyOz + H2O
Ca(OH)2 → CaO + H2O
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37. Decomposition Reactions (cont)
Metals with polyatomic ions containing oxygen PbCO3 → PbO + CO2
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38. Decomposition Problems
Predict the products and balance. NaCl → Al(OH)3 → Ag2O → Al2(CO3)3 →
Na + Cl2
Al2O3 + 3 H2O
Ag + O2
Al2O3 + 3 CO2
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39. Single Replacement Reactions
Single replacement reactions is where an element replaces a different element in a compound.
A + BX → B + AX
RULE: atom A will only replace atom B if it is MORE REACTIVE than element B.
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40. For Metals:
Use activity series on page 333 to tell which metals are more “active” or “reactive” than others K(s) + NaOH (aq)→ Ag(s) + KNO3 (aq)→
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41. For Nonmetals Usually involves Halogens
Activity Decreases as you move down a group F2
Cl2 ACTIVITY DECREASES
Br2 I2
F2 + AgI→
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42. Double Replacement Reactions
Double replacement reactions: cations in two compounds switch places. AY + BX → BY + AX AgNO3 + HCl → HNO3 + AgCl Usually happens in solutions and in one of the following ways
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43. #1 One of new products is a solid (precipitate, ppt)
___Na2S (aq) +__Cd(NO3)2 (aq) → _____(aq) + ____(ppt)
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44. #2 One product may bubble out as a gas
___NaCN (aq) +___H2SO4 (aq) → ______(aq) + _____(g)
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45. #3 Products may be covalent compounds like water
__CaCO3 (aq) +__HCl (aq) → ____(aq) + ____(l) + ___(g)
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46. Combustion Reactions
Combustion reaction is when something combines with oxygen and releases a large amount of energy as heat or light.
Combustion of hydrocarbons results in CO2 and water
CxHy + O2 → CO2 + H2O
CH4 + 2 O2 → CO2 + 2 H2O
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47. Chemical Reactions
Complete the following equations and identify the type of reaction HBr (l) → CH3CH2OH (l) +O2 (g) → Cl2 + NaBr → FeS (s) + HCl (l) → Al (s) + S (s) →
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48. Chemical Reactions
gallium hydroxide reacts with lithium nitrate nickel (II) reacts with copper (III) sulfate potassium chloride breaks down cobalt (II) reacts with oxygen pentacarbon decahyrdogen reacts with oxygen
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49. Essential Questions
What are the 5 types of chemical reactions? How can you tell which type of reaction is taking place? How can you predict the products of chemical reactions?
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50. Chapter 11 Section 2 Assignment
P 339 #22, P #49, 52, 59 (not c), 60, 63, 70, 71
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