Chapter 9

Predicting Reaction Products

1. Single Replacement Reactions

• Single Replacement Reactions occur when one element replaces another in a compound.

• A metal can replace a metal (+) OR a nonmetal can replace a nonmetal (-).

• element + compound compound + elementA + BC AC + B (if A is a metal) ORA + BC BA + C (if A is a nonmetal)

(remember the cation always goes first!)

When H2O splits into ions, it splits intoH+ and OH- (not H+ and O2- !!)

Single Replacement Reactions

• Predict the products of the following reaction:

• Aluminum metal reacts with aqueous hydrochloric acid (HCl).

Al(s) + HCl(aq)

Al(s) + HCl(aq) AlCl3(aq) + H2(g)

Practice

1. Al + Sn3P2 →

2. Cr(NO3)3 + Pb →

3. F2 + Na2O →

4. Na + water →

2. Double Replacement Reactions

• Double Replacement Reactions occur when the cations in two compounds switch places.

• compound + compound compound + compound

• AB + CD AD + CB

Double Replacement Reactions

• To build your two new compounds switch the cations. Check ion charges to build neutral compounds and write the cation first.

• Example:

AgNO3(aq) + NaCl(s)

• Another example:

K2SO4(aq) + Ba(NO3)2(aq)

AgCl(s) + NaNO3(aq)

KNO3(aq)+ BaSO4(s)

Practice1. HCl + AgNO3

2. CaCl2 + Na3PO4

3. Pb(NO3)2 + BaCl2

4. FeCl3 + NaOH

3. Decomposition Reactions• The simplest decomposition reactions

occur when a binary compound breaks up into its elements.

Compound Element + Element

• In general: AB A + B

• Example: 2 H2O 2H2 + O2

• Example: 2 HgO 2Hg + O2

Decomposition

PbO2(s)

AlN(s)

Practice

1. Mg3P2 →

2. LiCl →

4. Synthesis reactions• The simplest Synthesis reactions occur

when two elements combine and form a binary compound.

element + element compound

• Basically: A + B AB• Example: 2H2 + O2 2H2O

• Example: Fe + Cl2 FeCl2

Synthesis

Na(s) + Cl2(g)

Practice

1. Mg(s) + F2(g)

2. Al(s) + O2(g)

Combustion

• Combustion reactions combine a hydrocarbon with oxygen to produce carbon dioxide and water. C5H12 + O2 CO2 + H2O

Practice

1. C10H22 + O2

2. C12H22O11 + O2

Predicting the Products of Reactions – In Class Examples (In Notebook)

• HgO Hg + O2

• Al + Pb(NO3)2 Pb + Al(NO3)3

• K + water H2 + KOH

• N2O5 N2 + O2

• PbCl2 + Li2SO4 LiCl + PbSO4

Predicting the Products of Reactions – In Class Examples

• Cl2 + LiI LiCl + I2

• H2 + O2 H2O

• AgNO3 + K2SO4 KNO3 + Ag2SO4

• CH3OH + O2 CO2 + H2O

• Pb + Cu(NO3)2 Cu + Pb(NO3)2 or Pb(NO3)4

Predicting the Products of Reactions – In Class Examples

• C3H8 + O2 CO2 + H2O

• MgBr2 + FePO4 Mg3(PO4)2 + FeBr3

• Li2S Li + S

• K + Br2 KBr

Homework

“6 example problems” (on the back of Prediction of Reaction Products – In Class Examples).