1. Warm-Up predict the Molecular Geometry for each
PBr3
XeF5+
ClF4+

2. UNIT 4 – What’s in a name

3. Balancing Chemical Equations
In Balanced Chemical Equations, each side of the equation has the same number of atoms of each element
Coefficients are used to balance chemical equations

4. Rules for Balancing Equations
1. Determine the correct formulas for the reactants and products
2. Write the formulas for the reactants on the left side of the arrow. Write the formulas for the products on the right side of the arrow
Begin 3rd 1/18/02, 4th, & 5th

5. Rules Continued
3. Count the number of atoms of each element present on both sides of the equation
4. Balance the elements one at a time by placing coefficients in front of the formula.
5. Check to make sure each atom is balanced

6. Additional Rules
6. Check to make sure that all coefficients are in the lowest possible ratio
**If no coefficient is written, the coefficient is assumed to be “1”

8. Na (s) + Br2 (g)  NaBr (aq)
Examples
Balance the following
H2 (g) + O2 (g)  H2O (l)
Na (s) + Br2 (g)  NaBr (aq)
AgNO3 (aq) + Cu(s)  Cu(NO3)2 (aq) + Ag(s)

9. Practice Balance the following Equations
FeCl3 + NaOH  Fe(OH)3 + NaCl
CuCl2 + NaI  CuI2 + NaCl
H2O2  H2O + O2

10. Balancing Equations
AgI + Fe2(CO3)3  FeI3 + Ag2CO3
Al4C3 + H2O  CH4 + Al(OH)3

11. Balance the following equations
KMnO4 + Be3N2  K3N + Be(MnO4)2 Fe + O2  Fe2O3 Al2O3 + H2  Al + H2O SnO2 + H2  Sn + H2O

12. Balance the following Equations
1) C6H6 + O2  CO2 + H2O
2) Ni(OH)2 + HCl  NiCl2 + H2O
3) Al(NO3)3 + H2SO4 Al2(SO4)3 + HNO3
4) Pb(NO3)2 + CuSO4 PbSO4 + Cu(NO3)2

13. Practice Balancing Equations
CH4 + O2  H2O + CO2
Fe + Br2  FeBr3
Sn(NO2)4 + K3PO4  KNO2 + Sn3 (PO4)4
C2H6 + O2  CO2 + H2O
C3H8O3 + O2  CO2 + H2O

14. Balance the following equations:
Warm-Up
Balance the following equations:
SnO2 + H2  Sn + H2O
Mg(OH) HCl  MgCl H2O
C6H12O O2  CO H2O

15. Chemical Reactions
Chemical reaction, substances join together to form new substances
The original substances present are called REACTANTS
The new substances formed are called PRODUCTS

16. Additional Symbols in Chemical Reactions
+ used to separate reactants or products
(s) means chemical is in solid state
(l) means chemical is in liquid state
(g) means chemical is in gas state
(aq) means aqueous which means the chemical is dissolved in water

17.  means something is added to the reaction Usually this is heat
Other Symbols
 means something is added to the reaction
Usually this is heat
Pt means a catalyst (Pt) is added

18. Skeleton Equations
Skeleton (Formula) Equation- the rough form of an equation
It only shows the framework for the chemical reaction
Example: Fe + Cl2  FeCl3
Question Why is Chlorine written as Cl2?

19. Diatomic Molecules occur in nature
They are shown as single atoms because the molecules formed are more stable than the individual atoms
Diatomic Molecules are Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodine
They are written as H2, N2, O2, F2, Cl2, Br2, I2

20. Write Skeleton Equations/Balance Equations
Solid Sodium metal reacts with Oxygen gas to form solid Sodium Oxide
Solid sulfur reacts with Fluorine gas to form gaseous Sulfur Hexafluoride when heated
Nitrogen reacts with Hydrogen to form Ammonia (NH3) gas. Heat is required.

21. Write Skeleton Equations
Solid Magnesium metal reacts with Chlorine gas to form solid Magnesium Chloride.
Aqueous Silver Nitrate reacts with aqueous Sodium Chloride to form solid Silver Chloride and aqueous sodium nitrate

22. Write the Skeleton Formula for the following
Liquid Potassium Permanganate reacts with gaseous Hydrogen Chloride to produce aqueous potassium chloride and aqueous Manganese (II) Chloride and liquid water and chlorine gas.

23. Remember that the diatomic elements (Mr
**Remember that the diatomic elements (Mr. BrINClHOF) appear with a subscript of two when alone

24. Practice
Boron sulfide reacts violently with water to form dissolved boric acid (H3BO3) and hydrogen sulfide gas.
When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid (H3PO3) and aqueous hydrochloric acid (HCl).