Double Displacement (or Replacement) Reactions - PowerPoint PPT Presentation

1 / 33
About This Presentation
Title:

Double Displacement (or Replacement) Reactions

Description:

A reaction occurs when a piece of zinc is dipped into a solution of copper (II) nitrate. ... An zinc metal wire is dipped in hydrobromic acid. 3. The ... – PowerPoint PPT presentation

Number of Views:2013
Avg rating:3.0/5.0
Slides: 34
Provided by: terry2
Category:

less

Transcript and Presenter's Notes

Title: Double Displacement (or Replacement) Reactions


1
Double Displacement (or Replacement) Reactions
  • Also referred to as metathesis reaction
  • The two compounds exchange ions to produce two
    new compounds. It is easier to simply remember
    that the cations ( ions) exchange anions (-
    ions).
  • AB CD ? CB AD
  • NOTE always write the cation first then the
    anion.
  • Many reactions including precipitation and
    neutralization use the double displacement
    mechanism.

2
Double Displacement (or Replacement) Reactions
pp. 220, 223
3
NaCl(aq) AgNO3(aq) ? NaNO3(aq) AgCl(s)
Fig. 8-18, p. 221
4
Double Displacement (or Replacement) Reactions
  • PREDICT THE PRODUCT BALANCE
  • 1. MgSO4 LiOH ? ___________
  • 2. Pb(NO3)2 Na2CO3 ? ____________
  • 3. HNO3 Ba(OH)2 ? ___________

Answers are on the next slide.
5
Double Displacement (or Replacement) Reactions
  • ANSWERS
  • 1. MgSO4 2 LiOH ? Mg(OH)2 Li2SO4
  • 2. Pb(NO3)2 Na2CO3 ? PbCO3 2 NaNO3
  • 3. 2 HNO3 Ba(OH)2 ? Ba(NO3)2 2 H2O

Exchange cations
6
PRECIPITATION REACTION
  • A reaction where an insoluble solid is formed
    during a reaction between two aqueous solutions.
  • (aq) (aq) ? (aq) (s)
  • 2KI(aq) Pb(NO3)2(aq) ? 2KNO3(aq) PbI2(s)
  • NEUTRALIZATION REACTION
  • A reaction between an acid and a base which
    results in the production of a salt and water.
  • HA BOH ? (metal/nonmetal) H2O
  • HNO3(aq) KOH(aq) ? KNO3(aq) H2O(l)

Exchange cations
7
Table 9-3, p. 252
8
Fig. 9-13, p. 253
9
Single Displacement (or Replacement) Reactions
  • One element reacts with a compound to produce a
    different element and a new compound.
  • A BC ? AC B
  • NOTE if the element is a metal, it will replace
    the cation.
  • A BC ? C BA
  • NOTE if the element is a nonmetal, it will
    replace the anion.
  • Many reduction-oxidation reactions use the
    single displacement mechanism.

10
Single Displacement (or Replacement) Reactions
pp. 218, 220
11
Fig. 8-15, p. 218
12
Single Displacement (or Replacement) Reactions
  • PREDICT THE PRODUCT
  • 1. Ca HCl ?
  • 2. ZnBr2 I2 ?
  • 3. Cu AgNO3 ?

Answers are on the next slide.
13
Single Displacement (or Replacement) Reactions
  • ANSWERS
  • 1. Ca 2 HCl ? CaCl2 H2
  • 2. ZnBr2 I2 ? ZnI2 Br2
  • 3. Cu 2AgNO3 ? 2Ag Cu(NO3)2

14
Single-Replacement Redox Reactions
A reaction occurs when a piece of zinc is dipped
into a solution of copper (II) nitrate. Write the
conventional (molecular), ionic and net ionic
equations.
Fig. 9-9, p. 245
15
Single-Replacement Redox Reactions
  • Conventional (Molecular) Equation
  • Zn(s) Cu(NO3)2 (aq) ? Zn(NO3)2(aq) Cu(s)
  • Ionic Equation
  • Zn(s) Cu2(aq) NO3- (aq) ? Zn2(aq) NO3-
    (aq) Cu(s)
  • Net Ionic Equation
  • Zn(s) Cu2(aq) ? Zn2(aq) Cu(s)

16
Table 9-2, p. 245
17
Single-Replacement Redox Reactions
  • What happens if we place a piece of copper metal
    into a solution of zinc nitrate?
  • Evidence shows that copper is below zinc on the
    Activity Series, therefore copper will not
    replace zinc and no reaction occurs.
  • Cu(s) Zn(NO3)2(aq) ? NR

18
Reduction-Oxidation Reactions
  • A reaction in which electrons are transferred
    from one species to another.
  • Oxidation means the loss of electrons
  • Reduction means the gain of electrons
  • Rusting is a redox reaction
  • 4Fe (s) 3O2 (g) ? 2Fe2O3 (s)
  • As a reactant Fe has a zero oxidation state but
    as a product (in Fe2O3) iron has a 3 oxidation
    state. Three electrons per atom had to be
    transferred (lost) in order for this to happen.
    Note that oxygen also changed from a zero
    oxidation state to a 2- oxidation state. Oxygen
    needed to gain 2 electrons per atom.

19
Reduction-Oxidation Reactions
  • Oxidation means the loss of electrons
  • Reduction means the gain of electrons
  • Electrochemistry involves redox Rx.
  • Cu(s) 2AgNO3(aq) ? 2Ag(s) Cu(NO3)2(aq)
  • The reactant Cu has a zero oxidation state (all
    elements have a zero oxidation state) but as a
    product, in Cu(NO3)2,the copper atom loses two
    electrons and has a 2 oxidation state. The
    other atom which acquired the electrons donated
    by copper is silver. As a reactant silver has a
    1 oxidation state then by gaining electrons from
    copper, the ions are turned into elemental silver
    with a zero oxidation state.
  • The net effect of this reaction has metallic
    copper being oxidized to copper ions and silver
    ions being reduced to silver metal.

20
Fig. 16-2, p. 459
21
(No Transcript)
22
COMBINATION REACTION
  • A reaction in which two or more substances
    combine to form a single product.
  • A B C ? ABC
  • CaO(s) SO2(g) ? CaSO3(s)

23
C (s) O2 (g) ? CO2 (g)
Fig. 8-11, p. 214
24
  • DECOMPOSITION REACTION
  • A reaction in which a single compound reacts to
    give two or more substances, usually requiring a
    raise in temperature.
  • ABC ? A B C
  • 2KClO3(s) ? 2KCl(s) 3O2(g)

25
2H2O(l) ? 2H2(g) O2(g)
Fig. 8-13, p. 215
26
COMBUSTION REACTION
  • A reaction of a substance with oxygen, usually
    the rapid release of heat produces a flame.
  • CH O2 ? CO2 H2O
  • 2C4H10(g) 13O2(g) ? 8CO2(g) 10H2O(g)
  • (hint balance the Cs first, followed by the H
    then the Os)
  • Many times in a combustion reaction, heat energy
    is given off. In chemical terms this is called
    an exothermic reaction. Thermochemistry is field
    of chemistry which studies the transfer of heat
    in a reaction.
  • The thermodynamic equation representing this
    exothermic reaction is
  • 2C4H10(g) 13O2(g) ? 8CO2(g) 10H2O(g)
    heat (in Joules)

27
GAS FORMATION REACTIONS
  • A reaction that produces a gas from reactants not
    in the gaseous state.
  • 2 HCl (aq) ZnS (s) ? ZnCl2 (aq) H2S (g)
  • Zn (s) 2 HCl (aq) ? ZnCl2 (aq) H2 (g)
  • Many gas formation reactions involve two steps,
    first the double displacement reaction then the
    decomposition reaction of an unstable substance.
  • Na2CO3 2HCl ? 2 NaCl H2CO3
  • H2CO3 ? CO2 H2O
  • Besides carbonic acid (H2CO3), sulfurous acid
    (H2SO3) also decomposes into SO2 and water.

28
COMMON GAS FORMATION REACTIONS YOU SHOULD REMEMBER
  • NH4OH ? NH3 (g) H2O (l)
  • H2CO3 ? CO2 (g) H2O (l)
  • H2SO3 ? SO2 (g) H2O (l)

29
Table 8-3, p. 223
30
GROUP STUDY PROBLEM 17aWrite the following as
balanced chemical equations then classify each
reaction.
  • 1. Solid mercuric oxide decomposes at high
    temperatures to form metallic mercury and oxygen.
  • 2. Aqueous lead(II) nitrate reacts with aqueous
    magnesium bromide to produce the insoluble salt
    lead(II)bromide and soluble magnesium nitrate.
  • 3. At room temperature, aqueous ammonium
    carbonate is added to hydrochloric acid to
    produce aqueous ammonium chloride, water and
    carbon dioxide.
  • 4. Hydrochloric acid is poured over tin metal
    producing hydrogen gas and tin (IV) chloride.
  • 5. The combustion of ethanol, C2H5OH, results in
    the production of carbon dioxide and water.

31
PRACTICE PROBLEMS 17aWrite the following as
balanced chemical equations then classify each
reaction.
  • 1. Magnesium metal is combined with nitrogen at
    elevated temperatures to form magnesium nitride
    powder.
  • 2. An aqueous solution of soluble aluminum
    nitrate is mixed with aqueous sodium hydroxide to
    produce insoluble aluminum hydroxide and a sodium
    nitrate solution.
  • 3. Solid potassium sulfite is added to
    hydrochloric acid to produce sulfur dioxide,
    water, and potassium chloride.
  • 4. Acetic acid reacts with calcium hydroxide to
    produce calcium acetate and water.
  • 5. Lithium metal is dropped in water to produce
    lithium hydroxide and hydrogen gas.

3 Mg (s) N2 (g) ? Mg3N2 (s) combination, redox
Al(NO3)3 (aq) 3NaOH (aq) ? Al(OH)3(s)
3NaNO3(aq) ppt, DD
K2SO3 (s) 2HCl (aq) ? H2SO3 (aq) 2KCl (aq)
DD then H2SO3 (aq) ? H2O (l) SO2 (g)
decomposition overall Rx K2SO3 (s) 2HCl (aq)
? H2O (l) SO2 (g) 2KCl (aq)
2 HC2H3O2 (aq) Ca(OH)2 (aq) ? Ca(C2H3O2)2 (aq)
2H2O (l) DD, neutralization
2Li (s) 2H2O(l) ? 2LiOH (aq) H2 (g) SD, redox
32
GROUP STUDY PROBLEM 17bPREDICT THE PRODUCT
THEN WRITE A BALANCED EQUATION FOR EACH REACTIONS.
  • 1. The reaction between lead (II) acetate and
    ammonium carbonate solutions results in the
    formation of a white solid.
  • 2. An zinc metal wire is dipped in hydrobromic
    acid.
  • 3. The decomposition of sulfurous acid.
  • 4. Sodium hydroxide solution is added to
    sulfuric acid.
  • 5. Solid tin(II) sulfide is added to hydroiodic
    acid.

33
PRACTICE PROBLEMS 17bPREDICT THE PRODUCT THEN
WRITE A BALANCED EQUATION FOR EACH REACTIONS.
  • 1. Cadmium (II) iodide solution is added to
    aqueous potassium phosphate.
  • 2. Magnesium hydroxide solution is mixed with
    phosphoric acid.
  • 3. The decomposition of carbonic acid.
  • 4. The combustion of methanol, CH3OH.
  • 5. Solid cadmium reacts with a copper(II)
    sulfate solution.

3 CdI2 (aq) 2 K3PO4 (aq) ? Cd3(PO4)2 (s) 6 KI
(aq)
3 Mg(OH)2 (aq) 2 H3PO4 (aq) ? Mg3(PO4)2 (aq)
6 H2O (l)
H2CO3 (aq) ? CO2 (g) H2O (l)
2 CH3OH (l) 3 O2 (g) ? 2 CO2 (g) 4 H2O (l)
Cd (s) CuSO4 (aq) ? Cu (s) CdSO4 (aq)
Write a Comment
User Comments (0)
About PowerShow.com