1. Chapter 10: Chemical Reactions and Equations
Table of Contents
Chapter 10: Chemical Reactions and Equations
10.1: Reactions and Equations
10.2: Classifying Chemical Reactions
10.3: Reactions in Aqueous Solutions

2. Chapter 10: Chemical Reactions and Equations
Table of Contents
Chapter 10: Chemical Reactions and Equations
10.1: Reactions and Equations

3. Writing Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Writing Chemical Equations
A substance that undergoes a reaction (a chemical change) is called a reactant.
Each new substance formed is called a product.
Reactants  Products

4. Balancing Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Balancing Chemical Equations
The law of conservation of mass: Matter is neither created nor destroyed during a chemical reaction.
Remember that atoms don’t change in a chemical reaction; they just rearrange.

5. Balancing Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Balancing Chemical Equations
Only one rule:
Atoms on the left = Atoms on the right

6. Balancing Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Balancing Chemical Equations
Skeleton Equations are unbalanced chemical equations.
Not balanced!

7. Balancing Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Balancing Chemical Equations
Chemical Equations are balanced chemical equations.
coefficient
Balanced!

8. Balancing an Equation Basic Hints: 1. Do easiest elements first. 8 5 6
C5H12(g) + O2(g) → CO2(g) + H2O(l) 8 5 6
2. Save element coefficient for last.
PH O2(g) → P4O10(s) + H2O(g) 4 8 6
3. Save H & O for last, they often work themselves out.
Fe(OH)3 → Fe2O H2O 2 3

9. Balancing an Equation (NH4)2CO3(aq) + Al(NO3)3 (aq) →
4. Make odds even.
H3BO3 → B2O3(s) + H2O(l) 2 3
5. Group atoms together.
(NH4)2CO3(aq) Al(NO3)3 (aq) →
Al2(CO3)3(s) NH4NO3(aq) 3 2 6
6. Always double check!
Reactants’ atoms = Products’ atoms

10. Try it out! Balancing Chemical Equations Worksheet – try 1-5 now
The “Balancing Chemical Equations” side is due Thursday (tomorrow)
The “Balancing Equations Worksheet” side is for you if you need additional practice

11. Phases are indicated by the symbols (s), (l), (g), and (aq).
Chemical Reactions and Equations: Basic Concepts
Word Equations
Reactants  Products
Chemical Equations
Phases are indicated by the symbols (s), (l), (g), and (aq).

12. Energy and Chemical Equations
Chemical Reactions and Equations: Basic Concepts
Energy and Chemical Equations
The word energy is sometimes written in the chemical equation.

13. Basic Assessment Questions
Write a word equation, a skeleton equation, and a balanced for each of the following:
1. Solid lithium reacts with chlorine gas to produce solid lithium chloride. 2 2
2. Nitrogen gas reacts with oxygen gas to produce nitrogen dioxide gas. 2 2

14. Basic Assessment Questions
TRY IT OUT! Write a balanced chemical equation for the following reactions.
1. Solid potassium reacts with liquid water to produce hydrogen gas and a water solution of potassium hydroxide.
2. Calcium chloride and sodium carbonate in water solution produce solid calcium carbonate and a water solution of sodium chloride.

15. Try it out! Balancing Handout The ODDS are due Friday
The evens are for you if you need additional practice

16. Chapter 10: Chemical Reactions and Equations
Table of Contents
Chapter 10: Chemical Reactions and Equations
10.2: Classifying Chemical Reactions:

17. Recognizing Chemical Reactions
Chemical Reactions and Equations: Basic Concepts
Recognizing Chemical Reactions
When a substance undergoes a chemical change, it takes part in a chemical reaction.
After it reacts, it no longer has the same chemical identity.

18. Recognizing Chemical Reactions
Chemical Reactions and Equations: Basic Concepts
Recognizing Chemical Reactions
Many important clues indicate when chemical reactions occur.
Change in temperature
Change in color
Change in odor
Change in appearance such as phase

19. Major Classes of Reactions
Chemical Reactions and Equations: Basic Concepts
Major Classes of Reactions
If you can classify a reaction into one of five major categories by recognizing patterns that occur, you already know a lot about the reaction.
Click box to view movie clip.

20. A Synthesis Reaction A + B → AB
Chemical Reactions and Equations: Basic Concepts
A Synthesis Reaction
A + B → AB

21. A Decomposition Reaction
Chemical Reactions and Equations: Basic Concepts
A Decomposition Reaction
MCO3(s) → MO(s) + CO2(g)
MOH(s) → MO(s) + H2O(g)
MHCO3(s) → MO(s) + H2O + CO2(g)
AB → A + B

22. Single Displacement A + BC → B + AC
Chemical Reactions and Equations: Basic Concepts
Single Displacement
A + BC → B + AC

23. Activity Series
For this type of reaction to occur, the “replacing” element MUST be more reactive than the “replaced” element. See table of reduction potentials.
P. 288

24. METALS Most active HALOGENS Fluorine Chlorine Bromine Iodine
Lithium
Rubidium
Potassium
Calcium
Sodium
Magnesium
Aluminum
Manganese
Zinc
Iron
Nickel
Tin
Lead
Copper
Silver
Platinum
Gold
Most active
P. 288
HALOGENS
Fluorine
Chlorine
Bromine
Iodine
Least active

25. Activity Series F2(g) + 2NaBr(aq) → 2NaF(aq) + Br2(l)
More active than Br
Most active
HALOGENS
Fluorine
Chlorine
Bromine
Iodine
Br2(g) + 2NaF(aq) → NR
Less active than F
Least active

26. Double Displacement AB + CD → AD + CB
Chemical Reactions and Equations: Basic Concepts
Double Displacement
AB + CD → AD + CB

27. Combustion CxHyOz + O2 → CO2 + H2O
Chemical Reactions and Equations: Basic Concepts
Combustion
CxHyOz + O2 → CO2 + H2O

28. Basic Assessment Questions
Identify each of the following skeleton equations. Balance each equation if necessary.
synthesis
decomposition

29. You should be able to… Identify types of reactions Predict products
Look at reactants
What can they form? What is most likely?
We will get more practice tomorrow and Monday

30. Chapter 10: Chemical Reactions and Equations
Table of Contents
Chapter 10: Chemical Reactions and Equations
10.3: Reactions in Aqueous Solutions:

31. Chemical Reactions and Equations: Additional Concepts
REVIEW
With those at your table, please name and define the 5 classifications of reactions

32. An iron bar reacts with oxygen to form rust.
Chemical Reactions and Equations: Additional Concepts
REVIEW
An iron bar reacts with oxygen to form rust.
What kind of reaction will take place?
What will the products be?
Show rusted iron
H2O
4Fe(s) + 3O2(g) →
2Fe2O3(s)
synthesis

33. A copper wire is dipped into a silver nitrate solution.
Chemical Reactions and Equations: Additional Concepts
REVIEW
A copper wire is dipped into a silver nitrate solution.
What kind of reaction will take place?
What will the products be?
Copper wire – bent into a spiral
Small test tube
Add a couple of flakes of AgNO3
Dissolve in about 1.5 in water
Place copper in test tube
Cu(s) + AgNO3(aq) →
Ag(s) + CuNO3(aq)
Single displacement

34. Methane gas (CH4) from a Bunsen burner is lit on fire.
Chemical Reactions and Equations: Additional Concepts
REVIEW
Methane gas (CH4) from a Bunsen burner is lit on fire.
What kind of reaction will take place?
What will the products be?
CH4(g) + O2(g) →
CO2(g) + H2O(g)
Combustion

35. A Hydrogen balloon is lit on fire.
Chemical Reactions and Equations: Additional Concepts
REVIEW
A Hydrogen balloon is lit on fire.
What kind of reaction will take place?
What will the products be?
2H(g) + O2(g) →
2H2O(g)
synthesis / combustion

36. Reactions in Aqueous Solutions
Chemical Reactions and Equations: Additional Concepts
Reactions in Aqueous Solutions
Solutions of calcium chloride and ammonium sulfate are mixed to form solid calcium sulfate.
What kind of reaction will take place?
What will the products be?
LARGE test tube
40 mL (NH4)2SO4
20 mL CaCl2
Mix – be patient with the precipitate
CaCl2(aq) + (NH4)2SO4(aq) →
CaSO4(s) + 2NH4Cl(aq)
Double displacement

37. solid (precipitate) – see solubility rules H2O or gas – bubbles/odor
Chemical Reactions and Equations: Basic Concepts
Double Displacement
For aqueous solutions to react in a double displacement reactions, one of the products MUST come out of solution:
solid (precipitate) – see solubility rules
H2O or
gas – bubbles/odor

38. Reactions in Aqueous Solutions
Chemical Reactions and Equations: Additional Concepts
Reactions in Aqueous Solutions
precipitate
Check solubility on the back of the periodic table to see if a precipitate forms
If insoluble – it’s a precipitate

39. Reactions in Aqueous Solutions
Chemical Reactions and Equations: Additional Concepts
Reactions in Aqueous Solutions
To show all of the particles in solution as they really exist, a complete ionic equation can be written.
The sodium and nitrate ions are on both sides of the equation.
Such ions that do not participate in a reaction are called spectator ions.

40. Reactions in Aqueous Solutions
Chemical Reactions and Equations: Additional Concepts
Reactions in Aqueous Solutions
An ionic equation that does not show spectator ions but only the particles that participate in a reaction is called a net ionic equation.
In net ionic equations, (s), (l), (g) are never cancelled out.

41. Writing Ionic Equations
Chemical Reactions and Equations: Additional Concepts
Writing Ionic Equations
Write the balanced chemical equation for the reaction between aqueous solutions of strontium nitrate and potassium sulfate, which forms the precipitate strontium sulfate.
Then write the complete ionic and net ionic equations.

42. Writing Ionic Equations
Chemical Reactions and Equations: Additional Concepts
Writing Ionic Equations
strontium nitrate (aq) + potassium sulfate (aq) →
strontium sulfate (s) + ?
Write the correct skeleton equation.
2. Use coefficients to produce the balanced chemical equation.

43. Writing Ionic Equations
Chemical Reactions and Equations: Additional Concepts
Writing Ionic Equations
3. Write the complete/total ionic equation.
How to know when to split a compound:
Split only ionic (aq) compounds & strong acids (HCl, H2SO4, HNO3)
Leave molecules and weak acids alone! (HF, HCH3COO)

44. Writing Ionic Equations
Chemical Reactions and Equations: Additional Concepts
Writing Ionic Equations
4. Cross out the spectator ions, which are those that are on both sides of the equation.
5. That leaves the net ionic equation.

45. Writing Ionic Equations
Chemical Reactions and Equations: Additional Concepts
Writing Ionic Equations
Define:
Word equation
Skeleton equation
Balanced equation
Complete/total ionic equation
Net ionic equation
equation written in words
unbalanced, symbols
balanced, symbols
broken into ions
spectators removed

46. Try it out! Chemical Equations worksheet Due Tuesday, 13 March
(we will have time to work on it on Monday)
Due Tuesday, 13 March
Due TODAY at the end of class: Balancing Handout

47. Reactions that form water or a gas
Chemical Reactions and Equations: Additional Concepts
Reactions that form water or a gas
When hydrochloric acid and potassium hydroxide solutions are mixed, water results, together with an aqueous solution of potassium chloride.
Write the balanced chemical equation, a complete ionic equation, and a net ionic equation for this reaction.
The balanced chemical equation is the same as the skeleton equation.

48. Reactions that form water or a gas
Chemical Reactions and Equations: Additional Concepts
Reactions that form water or a gas
Write the complete ionic equation, which includes all of the ions.
Remove the spectator ions to produce the net ionic equation.

49. Additional Assessment Questions
Write a balanced chemical, complete ionic, and net ionic equations for the following reaction:
Aqueous solutions of lead(II) nitrate and ammonium chloride are mixed, forming a precipitate.

50. Answer Chemical: Complete Ionic: Net ionic:
Additional Assessment Questions
Answer
Chemical:
Complete Ionic:
Net ionic:

51. Additional Assessment Questions
Write a balanced chemical, complete ionic, and net ionic equations for the reaction between the following substances, which produce water:
nitric acid (HNO3) and aqueous barium hydroxide.

52. Answer Chemical: Complete ionic: Net ionic:
Additional Assessment Questions
Answer
Chemical:
Complete ionic:
Net ionic:
or, with coefficients reduced to lowest terms,

53. Additional Assessment Questions
Write a balanced chemical, complete ionic, and net ionic equations for the reaction between the following substances, which produce a gas:
hydrochloric acid and aqueous sodium cyanide, with production of a gas.

54. Answer Chemical: Complete ionic: Net ionic:
Additional Assessment Questions
Answer
Chemical:
Complete ionic:
Net ionic:

55. QUIZ
Tell the classification of the following particles either ionic, molecular, strong acid, weak acid, or element.
Tell if each of the following particles are soluble or insoluble. If soluble, then put the phase as (aq) and show how the particle dissolves (splits). If insoluble, put the appropriate phase (s), (l), (g).