Predicting Reactions

1
Predicting Reactions
2
Terminology

• Na(s) H2O(l) ? NaOH(aq) H2(g)
• Sodium and water are the reactants
• Reactants the starting materials for a reaction
• Sodium hydroxide and hydrogen are the products
• Products what is created by the reaction

3
Symbols in Reactions

• Na(s) H2O(l) ? NaOH(aq) H2(g)
• (s)
• Solid
• (l)
• Liquid (does not describe a solution)
• (g)
• Gas
• (aq)
• Aqueous dissolved in water, solution

4
Symbols in Reactions

• Delta over the reaction arrow
• Heat is continually added to make the reaction
  happen
• Formula over the reaction arrow
• Catalyst
• Participates in the reaction but is not consumed
• Speeds up the reaction
• In this example, iron is a catalyst.

5
Diatomic Molecules

• Certain elements exist in nature as diatomic
  molecules
• Br2
• I2
• N2
• Cl2
• H2
• O2
• F2
• BrINClHOF
• Any time chemists refer to one of these elements
  in its natural state we are speaking of the
  diatomic molecule

6
Types of Reactions

• A B ? AB
• Synthesis
• AB ? A B
• Decomposition
• AB C ? AC B
• Single Replacement
• AB CD ? AD CB
• Double Replacement
• CXHYOZ O2 ? CO2 H2O
• Combustion Reaction

7
How to Tell Which is Which

• Does the reaction have oxygen as a reactant and
  carbon dioxide and water as products?
• Combustion
• Does your reaction have two or more chemicals
  combining to form one compound?
• Synthesis
• Does your reaction have one compound being broken
  into two or more compounds?
• Decomposition

8
How to Tell Which is Which

• Does the reaction have any reactants that are
  only one element?
• Single Replacement
• Does the reaction have two reactants and two
  products that switched partners?
• Double Replacement

9
Practice

• Classify each reaction as one of the five basic
  reaction types
• Al HCl ? AlCl3 H2
• Cu(OH)2 ? CuO H2O
• CH4 O2 ? CO2 H2O
• P4O10 H2O ? H3PO4
• AgNO3 NaOH ? AgOH NaNO3

10
Balancing Reactions

• Consider the following reaction
• H2 O2 ? H2O
• There is a problem with this reaction
• Where did the second oxygen atom go?
• Must have the same number of atoms of each type
  on both sides of the reaction.
• Balancing the reaction.

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Balancing Reactions

• In order to balance a reaction
• Change or add coefficients to compounds
• Never add a coefficient to one element in a
  compound
• Never add or change a subscript

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Balancing Practice

• H2 O2 ? H2O

13
Balancing Practice

• C3H8 O2 ? CO2 H2O

14
Balancing Practice

• FeCl3 Na2S ? NaCl Fe2S3

15
Balancing Practice

• Ca(NO3)2 Na3PO4 ? NaNO3 Ca3(PO4)2

16
Balancing Practice

• Na H2O ? NaOH H2

17
Balancing Practice

• C2H6 O2 ? CO2 H2O

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Predicting Reactions
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Predicting Reactions

• Solutions of copper(II) chloride and sodium
  carbonate are mixed
• What type of reaction is this?
• What are the names of the products?
• Which product is the precipitate?
• Insoluble ionic compounds will form precipitates
  during reactions.
• Precipitates are solids.

20
Predicting Double Replacement Reactions

• Solutions of copper(II) sulfate and sodium
  chloride are mixed
• Where is my precipitate?
• What are the names of my products?
• Why is there no precipitate?
• If two solutions of ionic compounds are mixed and
  no precipitate forms, then we say that no
  reaction has occurred.

21
Double Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Silver nitrate solution is mixed with a sodium
  sulfate solution.

22
Double Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Solutions of ammonium chloride and lead(II)
  acetate are mixed.

23
Double Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Solutions of copper(II) sulfate and iron(III)
  chloride are mixed.

24
Double Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Solutions of lead(II) nitrate and sodium iodide
  are mixed.

25
Predicting More Reactions
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A Series of Reactions

• Add 6M HCl to
• Copper
• Iron
• Magnesium
• Zinc
• What type of reaction is this?

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Single Replacement Predictions

• Write the balanced reaction for each metal.
• What is the gas being produced?
• Which metal is the most active?
• Which metal is the least active?

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Single Replacement Predictions

• Most Active
• Mg
• Zn
• Fe
• Cu
• Least Active
• A more complete listing is on your reference
  table.

29
Activity Series

• Most Active Elements are at the top
• These will replace anything below it in a
  compound
• These elements are more stable in compounds.
• Least Active Elements are at the bottom
• These elements are more stable by themselves.
• No Reaction Occurs when the elements are already
  in their more stable positions.

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Two Activity Series

• The two activity series are not connected.
• Please draw a big fat line between them on your
  reference table.

31
Single Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Aluminum metal is added to a solution of
  copper(II) sulfate

32
Single Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Magnesium metal is added to a solution of
  potassium chloride

33
Single Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Lithium metal is added to water.

34
Single Replacement Practice

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Chlorine gas is bubbled through a solution of
  sodium bromide.

35
Other Types of Reactions

• Predicting other types of reactions is as simple
  as following a pattern.
• You have all the patterns you need on your
  reference table.

36
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Calcium hydroxide is heated strongly.

37
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Propane (C3H8) is burned in oxygen.

38
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Powdered aluminum is added to liquid bromine

39
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Sucrose (C12H22O11) is burned in oxygen

40
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Hydrogen gas is mixed with nitrogen gas in the
  presence of an iron catalyst.

41
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Magnesium chlorate is heated strongly.

42
Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR.
  Balance the reaction using the lowest whole
  number coefficients possible.
• Sodium hydrogen carbonate is heated strongly.

43
Additional Practice Problems

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR and
  explain why. Balance the reaction using the
  lowest whole number coefficients possible.
• Fluorine gas is bubbled through an aluminum
  iodide solution.
• Nickel(II) carbonate is heated strongly.
• Solutions of zinc chloride and calcium nitrate
  are mixed.
• Warm calcium metal is added to chlorine gas.
• Acetone (C3H6O) is burned in air.

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1. 3F2(g) 2AlI3(aq) ? 2AlF3(aq) 3I2(s)
2. This
3. ZnCl2(aq) Ca(NO3)2(aq) ? Zn(NO3)2(aq)
   CaCl2(aq) No Reaction
4. Ca(s) Cl2(g) ? CaCl2(s)
5. C3H6O(l) 4O2(g) ? 3CO2(g) 3H2O(g)

45
Additional Practice Problems.

• For the following reactions, write the complete
  reaction that occurs using all appropriate
  symbols. If no reaction occurs write NR and
  explain why. Balance the reaction using the
  lowest whole number coefficients possible.
• Silver metal is added to molten sulfur.
• Tin metal is added to a solution of manganese(II)
  chloride.
• A solution of carbonic acid (H2CO3) is warmed.
• Potassium metal is added to water.
• Solutions of barium chloride and aluminum sulfate
  are mixed
• Methane gas is burned in air

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• 2Ag(s) S(l) ? Ag2S(s)
• No Reaction
• H2CO3(aq) ? H2O(l) CO2(g)
• 2K(s) 2H2O(l) ? 2KOH(aq) H2(g)
• 3BaCl2(aq) Al2(SO4)3(aq) ? 3BaSO4(s)
  2AlCl3(aq)
• CH4(g) 2O2(g) ? CO2(g) 2H2O(l)

47

• 3BaCl2(aq) Al2(SO4)3(aq) ? 3BaSO4(s)
  2AlCl3(aq)

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Why Do We Have No Reaction?

• Solutions of ammonium chloride and potassium
  phosphate are mixed.
• Write the balanced reaction that would occur if
  this reaction happened

49
Why No Reaction?

• 3NH4Cl(aq) K3PO4(aq) ? (NH4)3PO4(aq) 3KCl(aq)
  
• What happens to ionic compounds when they
  dissolve in water?
• NH4Cl really looks like NH4(aq) and Cl-(aq)
• K3PO4 really looks like 3K(aq) and PO43-(aq)
• 3NH4(aq) 3Cl-(aq) 3K(aq) PO43-(aq) ?
  3NH4(aq) PO43-(aq) 3K(aq) 3Cl-(aq)
• No difference from one side to the other.
• Everything cancels out.

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Net Ionic Equations

• Net Ionic Equations
• Write things that are ionized in solution as
  separate ions.
• Dissolved ionic compounds.
• Everything else write like normal.
• Dont write anything that cancels out from both
  sides.
• Things that cancel are called spectator ions
• Must be mass balanced and charge balanced.

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Net Ionic Practice Problems

• Solutions of barium chloride and potassium
  sulfate are mixed.

52
Net Ionic Practice Problems

• Solutions of ammonium carbonate and calcium
  chloride are mixed.

53
Net Ionic Practice Problems

• Magnesium is added to a solution of copper(II)
  nitrate

54
Net Ionic Practice Problems

• Solutions of sodium phosphate and lead(II)
  nitrate are mixed.

55
Net Ionic Practice Problems

• Solutions of sodium phosphate and lead(II)
  nitrate are mixed.
• 2Na3PO4(aq)3Pb(NO3)2(aq)?6NaNO3(aq)Pb3(PO4)2(s)
• 6Na(aq)2PO43-(aq)3Pb2(aq)6NO3-(aq)?
• 6Na(aq) 6NO3-(aq) Pb3(PO4)2(s)
• 2PO43-(aq)3Pb2(aq) ? Pb3(PO4)2(s)

56
Net Ionic Practice Problems

• Solutions of sodium phosphate and lead(II)
  nitrate are mixed.