1. Chapter 10: Chemical Reactions
How can you tell there is a chemical Change?
Temperature
Light
Color
Gas Bubbles

2. The Chemical Equation: Section 1
What do we start with?
Reactants = Starting substances
Products = Substances formed

3. The Word Equation Describing the reaction
Reactant 1 + Reactant 2 --> Products
Iron(s) + chlorine(g) --> Iron (III) chloride(s)
How is this Read:
Iron and chlorine react to produce iron (III) chloride

4. The Skeleton Equation Replace the words with the symbols
Iron(s) + chlorine(g) --> Iron (III) chloride(s)
Fe(s) +
Cl2(g)
-->
FeCl3(s)
Whats Wrong with this Equation?
Count the number of atoms on each side of the arrow.
Needs to be balanced!
let’s practice skeleton equations first

5. Practice Makes Perfect
Write the skeleton equations for the following word equations
hydrogen(g) + bromine(g) --> hydrogen bromide (g)
H2(g) +
Br2(g)
-->
HBr(g)
carbon monoxide(g) + oxygen(g) --> carbon dioxide(g)
CO(g) +
O2(g)
-->
CO2(g)
potassium chlorate(s) --> potassium chloride(s) + oxygen(g)
KClO3(S)
-->
KCl(S) +
O2(g)

6. The Balanced Chemical Equation
Remember: Matter is neither created nor destroyed
Fe(s) +
Cl2(g)
-->
FeCl3(s)
Count the number of atoms of each element Cl Fe Cl + Fe
--> Cl
What’s the Problem?

7. + --> Now Count the atoms. 2 2 3 How do We Fix It?
Balance the equation 2 2 3
Fe(s) +
Cl2(g)
-->
FeCl3(s) Cl Fe Cl Fe Cl +
--> Cl Fe Fe Cl
Now Count the atoms.
Remember: Matter is neither created nor destroyed

8. 5 Easy Steps for Balancing Equations
Write the skeleton equation
Count the atoms of the reactants
Count the atoms of the the products
Place coefficients to make the # of atoms equal on both sides of the equation
Write the coefficients in their lowest possible ratio

9. Practice Write chemical equations for each of the following reactions
In water, Iron (III) chloride reacts with sodium hydroxide, producing solid iron (III) hydroxide and sodium chloride.

10. Liquid carbon disulfide reacts with oxygen gas, producing carbon dioxide gas and sulfur dioxide gas.

11. Solid zinc and aqueous hydrogen sulfate reat to produce hydrogen gas and aqueous zinc sulfate.

12. --> A + B AB CO(g) + O2(g) --> CO2(g) Synthesis Reactions:
Two Elements combine to produce one new compounds
--> A + B AB
CO(g) +
O2(g)
-->
CO2(g)

13. B --> A + AB 2H2(g) + O2(g) --> 2H2O(g) Combustion Reaction
Oxygen comines with a substance and releases energy in the form of heat and light. B
--> A + AB
2H2(g) +
O2(g) -->
2H2O(g)

14. The solids aluminum and sulfur react to produce aluminum sulfide

15. Water and dinitrogen pentoxide gas react to produce aqueous hydrogen nitrate.

16. The gases nitrogen dioxide and oxygen react to produce dinitrogen pentoxide gas.

17. Ethane gas (C2H6) burns in air, producing carbon dioxide gas and water vapor

18. Single compound breaks down into 2 or more elements
Decomposition Reactions
Single compound breaks down into 2 or more elements AB
-->
A + B
Example:
NH4NO3(s)
-->
N2O(g) +
2H2O(l)
2NaN3(s)
-->
2Na(s) +
3N2(g)

19. 1 element replaces the atoms of another element in a compound
Replacement Reactions
Single Replacement:
1 element replaces the atoms of another element in a compound A
+ BX
--> AX
+ B
Double Replacement:
The exchange of ions between two compounds AX
+ BY
--> AY
+ BX

20. Practice K K(S) + ZnCl2(aq) --> Zn(s) Cl(aq) + + +
Cl2(g) + HF(aq) -->
Cl(aq) H
F(g) + Fe
Fe(s) + Na3PO4(aq) -->
Na(s)
PO4(aq) +

21. Practice AX + BY --> AY + BX
Aqueous lithium iodide and aqueous silver nitrate react to produce solid silver iodide and aqueous lithium nitrate.

22. Practice AX + BY --> AY + BX
Aqueous barium chloride and aqueous potassium carbonate react to produce solid barium carbonate and aqueous potassium chloride.

23. Practice
Aqueous sodium oxalate and aqueous lead(II) nitrate react to produce solid lead(II) oxalate and aqueous sodium nitrate.

24. Section 3: Reactions in Aqueous Solutions
Terms to know:
solutes: substance dissolved in water
solvent: what the substance is
dissolved in (ie. water)

25. Complete Ionic Equation
Shows all particle in a solution
Here’s the equation +
--> +
2Na+(aq)
2NaOH(aq)
2OH-(aq)
Cu2+
CuCl2(aq)
2Cl-(aq)
2NaCl(aq)
Cu(OH)2(s)
Cu(OH)2(s)
2Na(aq)
2Cl(aq)
Now Separate ALL the ions in aqueous solution + + +
--> + +

26. + --> Spectator Ions Here’s the complete Ionic Equation
Ions that do not participate in a reaction
Here’s the complete Ionic Equation
2Na+(aq)
2OH-(aq)
Cu2+
2Cl-(aq)
2Na(aq)
2Cl(aq)
Cu(OH)2(s) +
-->
Now Cancel out all the ions that are NOT part of the reactions (ions that do not produce the solid)

27. + + + --> + Net Ionic Equation Remove the Spectator ions 2Na+(aq)
Includes only the particles that participate in a reaction
Here’s the net ionic equation with spectator ions cancelled
2Na+(aq) + +
2Cl-(aq) +
-->
2OH-(aq)
Cu2+
2Na(aq)
2Cl(aq) +
Cu(OH)2(s)
Remove the Spectator ions

28. 3 Types of Aqueous Reactions
1. Reactions that form Precipitates (solids)
2NaOH(aq) + CuCl2(aq) --> 2NaCl(aq) + Cu(OH)2(s).
2. Reactions that form Water
HBr(aq) + NaOH(aq) --> H2O(l) + NaBr(aq)
3. Reactions that form Gases
2HI(aq) + Li2S(aq) --> H2S(g) + 2LiI(aq)

29. Practice 1. Reactions that form Precipitates (solids)
2NaOH(aq) + CuCl2(aq) --> 2NaCl(aq) + Cu(OH)2(s).

30. Practice 2. Reactions that form Water
HBr(aq) + NaOH(aq) --> H2O(l) + NaBr(aq)
H+(aq)
Br-(aq)
Na+(aq)
OH(aq)
H2O(l)
Na+(aq)
Br-(aq)
H+(aq) + + +
OH(aq)
--> + +
H2O(l)
Write the complete Ionic equation
Cancel the spectator ions
Write the net ionic equation +
-->

31. Practice 3. Reactions that form Gases
2H(aq)
2HI(aq) + Li2S(aq) --> H2S(g) + 2LiI(aq)
2I(aq)
2Li(aq)
S(aq)
H2S(g)
2Li(aq)
2I(aq)
2H(aq) + + +
S(aq)
-->
H2S(g) + +
Write the complete Ionic equation
Cancel the spectator ions
Write the net ionic equation +
-->