Predicting Reaction Products

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Chapter 9

• Predicting Reaction Products

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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 element
• A BC ? AC B (if A is a metal) OR
• A BC ? BA C (if A is a nonmetal)
• (remember the cation always goes first!)
• When H2O splits into ions, it splits into
• H and OH- (not H and O2- !!)

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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)

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Practice

1. Al Sn3P2 ?
2. Cr(NO3)3 Pb ?
3. F2 Na2O ?
4. Na water ?

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2. Double Replacement Reactions

• Double Replacement Reactions occur when the
  cations in two compounds switch places.
• compound compound ? compound compound
• AB CD ? AD CB

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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)
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Practice

• HCl AgNO3 ?
• CaCl2 Na3PO4 ?
• Pb(NO3)2 BaCl2 ?
• FeCl3 NaOH ?

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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

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Decomposition

• PbO2(s) ?
• AlN(s) ?

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Practice

1. Mg3P2 ?
2. LiCl ?

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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

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Synthesis

• Na(s) Cl2(g) ?

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Practice

1. Mg(s) F2(g) ?
2. Al(s) O2(g) ?

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Combustion

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

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Practice

1. C10H22 O2 ?
2. C12H22O11 O2 ?

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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

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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

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Predicting the Products of Reactions In Class
Examples

• C3H8 O2 ? CO2 H2O
• MgBr2 FePO4 ? Mg3(PO4)2 FeBr3
• Li2S ? Li S
• K Br2 ? KBr

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Homework

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