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

UNIT 4 – What’s in a name

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

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

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

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”

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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)

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

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

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

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

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

Balance the following equations: Warm-Up Balance the following equations: SnO2 + H2  Sn + H2O Mg(OH)2 + HCl  MgCl2 + H2O C6H12O6 + O2  CO2 + H2O

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

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

 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

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?

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

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.

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

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.

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

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).