Drill #4B 2/10/15 Predict the products and balance the equation for the following double-replacement reaction: Na2CrO4 (aq) + Ba(OH)2 (aq) →

Drill #3 2/10/15 Translate and predict products for the following reactants: calcium hydroxide + phosphoric acid FeCl3 + NH4OH

Answer 1 Na2CrO4 (aq) + 1 Ba(OH)2 (aq) → 2 NaOH (aq) + 1 BaCrO4 (s) BaCrO4 is the precipitate (solid) – how do we know this? Solubility Rules

Agenda Pass fwd 9-2 Practice Problems.

Drill # 4A 2/9/15 Write the balanced chemical equations for the following: aluminum bromide + chlorine yield aluminum chloride + bromine Potassium chlorate when heated yields potassium chloride + oxygen gas Hydrogen + nitrogen monoxide yield water + nitrogen

Agenda Predicting Products Precipitation Reactions and Solubility Rules Lab on Wed

Predicting Products of Reactions

Synthesis Reactions: A + B  AB Element + Element  Compound There are other forms, but for your test, it will always be an ionic compound To predict the products of a synthesis reaction, just cross the charges of the elements Example: Li + Br2  ? Li + Br2  LiBr 2Li + Br2  2LiBr (balanced)

Synthesis Practice Mg + N2  ? Mg + N2  Mg3N2 3Mg + N2  Mg3N2 Mn + Cl2  ? (Use Mn2+) Mn + Cl2  MnCl2 (already balanced) K + O2  ? K + O2  K2O 4K + O2  2K2O

Decomposition Reactions AB  A + B Compound  Element + Element There are other forms, but for your test, we will always end with two elements. To predict the product, just separate the compound into elements. Example: CaO  ? CaO  Ca + O2 2 CaO  2 Ca + O2 DON’T FORGET THE DIATOMIC ELEMENTS! H2, N2, O2, F2, Cl2, Br2, I2

Decomposition Practice PbI2  ? PbI2  Pb + I2 (already balanced) NH3  ? NH3  N2 + H2 2 NH3  N2 + 3 H2 Li2S  ? Li2S  Li + S Li2S  2 Li + S AlF3  ? AlF3  Al + F2 2AlF3  2Al + 3F2

Single Replacement Reactions Element + Compound  New Element + New Compound 2 forms: A + BC  AC + B (A is a metal) OR X + YZ  YX + Z (X is a nonmetal)

Single Replacement Rxns. Cont. You must use an Activity Series to determine if there is a reaction. If the free metal is above the bonded metal on the Metal Activity Series (on the back of your Periodic Table), the free metal will take the place of the bonded metal. (If it is below, then NR – no reaction) If the free nonmetal is above the bonded nonmetal on the Periodic Table, the free nonmetal will take the place of the bonded nonmetal. (If it is below, then NR.)

Single Replacement Practice Fe + CuSO4  ? (use Fe2+) Fe + CuSO4  FeSO4 + Cu (already balanced) Why? Fe is above Cu on the Activity Series Ca + HgO  ? Ca + HgO  CaO + Hg (already balanced) Why? Ca is above Hg on the Activity Series

Single Replacement Practice Ni + Mn2O3  ? (Use Ni2+) Ni + Mn2O3  NR (no need to balance!) Why? Ni is below Mn on the Activity Series Al + FeCl2  ? Al + FeCl2  Fe + AlCl3 Why? Al is above Fe on the Activity Series 2 Al + 3 FeCl2  3 Fe + 2 AlCl3

Single Replacement Practice MnCl3 + F2  ? MnCl3 + F2  MnF3 + Cl2 Why? F is above Cl on the Periodic Table 2 MnCl3 + 3 F2  2 MnF3 + 3 Cl2 S + Na2O  ? S + Na2O  NR (no need to balance!) Why? S is below O on the Periodic Table

Double Replacement Reactions AB + CD  AD + CB Compound + Compound  New Compound + New Compound To predict, swap ion pairs and re-cross charges. Example: Fe(OH)2 + H2SO4  ? Fe(OH)2 + H2SO4  FeSO4 + HOH (H2O) Fe(OH)2 + H2SO4  FeSO4 + 2 H2O

Double Replacement Practice KI + PbCl2  ? KI + PbCl2  KCl + PbI2 2 KI + PbCl2  2 KCl + PbI2

Combustion Reactions CxHx + O2  CO2 + H2O Any reaction between a compound of carbon and hydrogen (CxHx) and oxygen will produce the same two products – carbon dioxide and water! Example: CH4 + O2  ? CH4 + O2  CO2 + H2O CH4 + 2 O2  CO2 + 2 H2O

Combustion Practice C6H6 + O2  ? C6H6 + O2  CO2 + H2O C2H5OH + O2  ? C2H5OH + O2  CO2 + H2O C2H5OH + 3 O2  2 CO2 + 3 H2O

Precipitation Reactions No ionic compound is entirely insoluble in water, however compounds of low solubility can be considered insoluble for most practical purposes. There are some general guidelines to help predict whether a compound made of a certain combination of ions is soluble.

Solubility Rules Table Use this table to determine if precipitation will occur. Precipitation occurs when the attraction between the ions is greater than the attraction between the ions and surrounding water molecules. Precipitate = solid

Assignment Complete the “Double Replacement Reactions and the Solubility Rules” worksheet Directions: use the solubility rules handout to determine the correct phase for each product Review WS