Deck 5: Classification and Balancing of Chemical Reactions

Question 1

In a balanced chemical equation

A)there are equal numbers of atoms on each side of the reaction arrow.
B)there are equal numbers of molecules on each side of the reaction arrow.
C)there are always the same number of products as there are reactants.
D)the number of atoms present in a reaction can vary when the conditions change during the reaction.
E)none of the above

Answer 1

there are equal numbers of atoms on each side of the reaction arrow.

Question 2

When the reaction shown is correctly balanced,the coefficients are:
________ KClO₃ → ________ KCl + ________ O₂

A)1;1;1
B)2;2;2
C)2;2;3
D)2;2;1
E)4;4;6

Answer 2

2;2;3

Question 3

Which statement regarding balanced chemical equations is not true?

A)The number of each kind of atom must be the same on each side.
B)Coefficients are used in front of formulas to balance the equation.
C)Subscripts may be changed to make an equation simpler to balance.
D)When no coefficient is written in front of a formula,the number "one" is assumed.
E)Reactants are written to the left of the arrow.

Answer 3

Subscripts may be changed to make an equation simpler to balance.

Question 4

Which is the correct equation for the reaction of magnesium with hydrochloric acid to produce hydrogen and magnesium chloride?

A)Mg + 2 HCl → H₂ + MgCl₂
B)Mg + HCl → H + MgCl
C)2 Mg + 6 HCl → 3 H₂ + 2 MgCl₂
D)Mg + 2 HCl → 2 H + MgCl₂
E)Mg + 3 HCl → 3 H + MgCl₂

Question 5

When the reaction shown is correctly balanced,the coefficients are:
________ Li + ________ Br₂ → ________ LiBr

A)1;1;1
B)1;2;2
C)1;2;1
D)2;2;1
E)2;1;2

Question 6

Which of the following equations is not balanced?

A)C₇H₁₆ + O₂ → 7 CO₂ + 8 H₂O
B)K₂CrO₄ + Pb(NO₃)₂ → 2 KNO₃ + PbCrO₄
C)4 Fe₃O₄ + O₂ → 6 Fe₂O₃
D)3 AgNO₃ + (NH₄)₃PO₄ → Ag₃PO₄ + 3 NH₄NO₃
E)2 Al₂O₃ → 4 Al + 3 O₂

Question 7

When the reaction shown is balanced,there are ________ atoms of oxygen and ________ atoms of hydrogen on each side.
_______ (NH₄)₂SO₄(aq)+ _______ Ba(C₂H₃O₂)₂(aq)→ _______ BaSO₄(s)+ _______ NH₄C₂H₃O₂(aq)

A)6;11
B)16;18
C)8;14
D)4;7
E)16;28

Question 8

Consider the balanced equation shown and identify the statement that is not true.
Na₂SO₄(aq)+ BaCl₂(aq)→ 2 NaCl(aq)+ BaSO₄(s)

A)The coefficient of sodium sulfate is one.
B)Barium sulfate is produced in solid form.
C)Barium chloride is dissolved in water.
D)The products are barium sulfate and sodium chloride.
E)2 NaCl (aq)could also be correctly written as Na₂Cl₂ (aq).

Question 9

When the following reaction is balanced,the coefficient in front of carbon dioxide is:
________ C₅H₁₂ + ________ O₂ → ________ CO₂ + ________ H₂O

A)5
B)6
C)12
D)10
E)11

Question 10

The balanced equation for the reaction occurring when iron(III)oxide,a solid,is reduced with pure carbon to produce carbon dioxide and molten iron is

A)2 Fe₃O(s)+ C(s)→ 6 Fe(l)+ CO₂(g).
B)2 FeO₃(s)+ 3 C(s)→ 2 Fe(l)+ 3 CO₂(g).
C)4 Fe₂O_3(s) + 6 C s)→ 8 Fe l)+ 6 CO₂(g).
D)2 FeO(s)+ C s)→ 2 Fe l)+ CO₂(g).
E)2 Fe₂O_3(s) + 3 C(s)→ 4 Fe l)+ 3 CO₂(g).

Question 11

Consider the reaction shown and identify the statement that is not true.
CaCO₃(s) CaO(s)+ CO₂(g)

A)This reaction is balanced as written.
B)The reactant must be heated for this reaction to occur.
C)The products are a solid and a gas.
D)Water must be present for this reaction to occur.
E)There are no solutions used in this reaction.

Question 12

When the reaction shown is correctly balanced,the coefficients are:
________ C₆H₁₄(l)+ ________ O₂(g)→ ________ CO₂(g)+ ________ H₂O(g)

A)1;6;6;7
B)2;19;12;14
C)1;3.5;6;7
D)1;9.5;6;7
E)2;16.5;12;7

Question 13

In the correctly balanced reaction,the coefficient for H₂O is:
________ Al(OH)₃ + ________ H₂SO₄ → ________ Al₂(SO₄)₃ + ________ H₂O

A)1
B)2
C)3
D)6
E)8

Question 14

When the reaction shown is correctly balanced,the coefficients are:
________ HNO₃ + ________ KOH → ________ KNO₃ + ________ H₂O

A)0;0;0;0
B)1;1;1;1
C)2;2;2;2
D)3;1;1;3
E)2;1;2;1

Question 15

In a precipitation reaction the insoluble product can be identified by the symbol

A)(aq).
B)(l).
C)(g).
D)(s).
E)none of the above

Question 16

When the reaction shown is correctly balanced,the coefficients are:
________ HBr + ________ Ca(OH)₂ → ________ CaBr₂ + ________ H₂O

A)2;1;1;1
B)1;1;1;2
C)2;1;1;2
D)2;2;1;1
E)2;1;2;2

Question 17

The scientific principle which is the basis for balancing chemical equations is

A)the Law of Conservation of Energy.
B)the Law of Conservation of Mass.
C)the Law of Conservation of Mass and Energy.
D)the Law of Definite Proportions.
E)Avogadro's Law.

Question 18

Which of the following equations is not balanced?

A)2 Na + 2 H₂O → 2 NaOH + H₂
B)C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
C)2 H₂ + O₂ → 2 H₂O
D)SO₂ + O₂ → SO₃
E)2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

Question 19

The balanced equation for the reaction occurring when calcium nitrate solution is mixed with sodium phosphate solution is

A)3 Ca(NO₃)₂(aq)+ 2 Na₃PO₄(aq)→ Ca₃(PO₄)₂(aq)+ 6 NaNO₃(aq).
B)2 Ca(NO₃)₂(aq)+ 3 Na₃PO₄(aq)→ 2 Ca₃(PO₄)₂(s)+ 6 NaNO₃(aq).
C)3 CaNO₃(aq)+ Na₃PO₄(aq)→ Ca₃PO₄(aq)+ 3 NaNO₃(s).
D)3 Ca(NO₃)₂(aq)+ 2 Na₃PO₄(aq)→ Ca₃(PO₄)₂(s)+ 6 NaNO₃(aq).
E)Ca(NO₃)₂(aq)+ 2 NaPO₄(aq)→ Ca(PO₄)₂(s)+ 2 NaNO₃(aq).

Question 20

When the following reaction is balanced,the coefficient in front of oxygen is:
________ C₈H₁₈ + ________ O₂ → ________ CO₂ + ________ H₂O

A)25
B)12
C)18
D)9
E)17

Question 21

Write and balance the following acid-base neutralization reaction:
KOH(aq)+ H₂SO₄ aq)→

Question 22

Which one of the following substances is produced during an acid/base (or neutralization)reaction?

A)H₂
B)H₂O
C)CO₂
D)NaOH
E)NaCl

Question 23

The balanced equation for the reaction between aqueous ammonium sulfate and aqueous barium acetate is

A)(NH₄)₂SO₄(aq)+ Ba(C₂H₃O₂)₂(aq)→ BaSO₄(s)+ NH₄C₂H₃O₂(aq).
B)(NH₄)₂SO₄(aq)+ Ba(C₂H₃O₂)₂(aq)→ BaSO₄(s)+ 2 NH₄C₂H₃O₂(aq).
C)NH₄SO₄(aq)+ BaC₂H₃O₂(aq)→ BaSO₄(s)+ NH₄C₂H₃O₂(aq).
D)(NH₄)₂SO₄(aq)+ Ba(C₂H₃O₂)₂(aq)→ BaSO₄(aq)+ 2 NH₄C₂H₃O₂(s).
E)(NH₄)₂SO₃(aq)+ Ba(C₂H₃O₂)₂(aq)→ BaSO₃(aq)+ NH₄C₂H₃O₂(aq).

Question 24

Which reaction is not an example of a redox reaction?

A)2 Hg(l)+ O₂(g)→ 2 HgO(s)
B)2 (NH₄)₃PO₄(aq)+ 3 Ba(NO₃)₂(aq)→ Ba₃(PO₄)₂(s)+ 6 NH₄NO₃(aq)
C)CH₄(g)+ 2 O₂(g)→ CO₂(g)+ 2 H₂O(g)
D)6 HCl(aq)+ 2 Al(s)→ 2 AlCl₃(aq)+ 3 H₂(g)
E)2 Al₂O₃(s)→ 4 Al(s)+ 3 O(g)

Question 25

The formation of which one of the compounds below will act as the driving force for an acid-base reaction?

A)H₂O
B)MgCl₂
C)NaNO₃
D)KOH
E)all of these

Question 26

Write and balance the following acid-base neutralization reaction:
HBr(aq)+ Li₂CO₃(aq)→

Question 27

All of the statements regarding redox reactions are true except

A)a reducing agent causes another substance to be reduced.
B)halogens usually behave as oxidizing agents because they readily gain electrons.
C)metal ions are produced when pure metals are oxidized.
D)when a substance is oxidized its charge (or oxidation number)decreases.
E)alkali metals often behave as reducing agents because they readily lose electrons.

Question 28

The reaction 2 AgNO₃(aq)+ K₂SO₄(aq)→ 2 KNO₃(aq)+ Ag₂SO₄(s)is an example of a(an)________ reaction.

A)acid-base
B)oxidation-reduction
C)precipitation
D)combustion
E)none of the above

Question 29

In a typical oxidation-reduction reaction the electrons are transferred

A)from the oxidizing agent to the reducing agent.
B)from what is being oxidized to the substance being reduced.
C)from what is being reduced to the substance being oxidized.
D)from what is being oxidized to the reducing agent.
E)none of these.

Question 30

When potassium hydroxide and hydrobromic acid are combined the products are

A)potassium bromide and water.
B)potasium bromate and water.
C)potassium bromide and hydrogen gas.
D)potassium hypobromite and water.
E)potassium bromite and hydrogen gas.

Question 31

All of the reactions shown are oxidation-reduction reactions except

A)N₂(g)+ O₂(g)→ 2 NO(g).
B)2 Fe₂O₃(s)→ 4 Fe(s)+ 3 O₂(g).
C)Zn(s)+ 2 HCl(aq)→ ZnCl₂(aq)+ H₂(g).
D)2 NaI(aq)+ Cl₂(g)→ 2 NaCl(aq)+ I₂.
E)K₂SO₄(aq)+ BaCl₂(aq)→ BaSO₄(s)+ 2 KCl(aq).

Question 32

Which reaction is an example of a precipitation reaction?

A)H₂CO₃(aq)→ H₂O(l)+ CO₂(g)
B)H₂SO₄(aq)+ Ca(OH)₂(aq)→ CaSO₄(aq)+ 2 H₂O(l)
C)6 HCl(aq)+ 2 Al(s)→ 2 AlCl₃(aq)+ 3 H₂(g)
D)FeCl₃(aq)+ 3 KOH(aq)→ Fe(OH)₃(s)+ 3 KCl(aq)
E)2 Hg(l)+ O₂(g)→ 2 HgO(s)

Question 33

Which of the following is not soluble in water?

A)potassium sulfide
B)iron(II)bromide
C)iron(III)hydroxide
D)iron(III)nitrate
E)ammonium sulfate

Question 34

Which reaction is an example of an acid-base reaction?

A)H₂CO₃(aq)→ H₂O(l)+ CO₂(g)
B)H₂SO₄(aq)+ Ca(OH)₂(aq)→ CaSO₄(aq)+ 2 H₂O(l)
C)6 HCl(aq)+ 2 Al(s)→ 2 AlCl₃(aq)+ 3 H₂(g)
D)FeCl₃(aq)+ 3 KOH(aq)→ Fe(OH)₃(s)+ 3 KCl(aq)
E)2 Hg(l)+ O₂(g)→2 HgO(s)

Question 35

The combination of ions least likely to produce a precipitate is

A)Ba²⁺ and SO₄^2-.
B)Pb⁺ and Cl^-.
C)Ca²⁺ and PO₄^3-.
D)Fe³⁺ and OH^-.
E)Mg²⁺ and C₂H₃O₂^-.

Question 36

When a solution of iron(III)nitrate is mixed with a solution of sodium hydroxide,a rust colored precipitate forms.This precipitate is probably

A)iron(III)nitrate.
B)sodium hydroxide.
C)sodium nitrate.
D)iron(III)hydroxide.
E)none of the above

Question 37

In order to form the salt calcium sulfate,which acid and base combination should you choose?

A)H₂SO₃ and CaOH
B)H₂SO₄ and CaOH
C) H₂SO₃ and Ca(OH)₂
D) H₂SO₄ and Ca(OH)₂
E)none of the above

Question 38

The combination of ions most likely to produce a precipitate is

A)Li⁺ and PO₄^3-.
B)Pb²⁺ and NO₃^-.
C)NH₄⁺ and SO₄^2-.
D)Fe³⁺ and OH^-.
E)Mg²⁺ and C₂H₃O₂^-.

Question 39

Which reaction is an example of both a precipitation and a neutralization?

A)H₃PO₄(aq)+ 3 KOH(aq)→ K₃PO₄(aq)+ 3 H₂O(l)
B)FeCl₃(aq)+ 3 KOH(aq)→ Fe(OH)₃(s)+ 3 KCl(aq)
C)(NH₄)₂CO₃(s)→ 2 NH₃(g)+ CO₂(g)+ H₂O(l)
D) H₂SO₄(aq)+ Ba(OH)₂(aq)→ BaSO₄(s)+ 2 H₂O(l)
E) 2 C(s)+ O₂(g)→ 2 CO(g)

Question 40

The following reaction can be classified as what type(s)of reaction(s)?
2 Al(OH)₃(aq)+ 3 H₂SO₄(aq)→ Al₂(SO₄)₃(s)+ 6 H₂O(l)

A)precipitation
B)acid-base neutralization
C)redox reaction
D)combustion
E)both A and B

Question 41

Match the following.
M(s)+ 2 LX(aq)→ 2 L(s)+ M (aq)

A)redox
B)acid-base
C)precipitation

Question 42

What is the typical net ionic equation for an acid-base neutralization of KOH and HCl?

A)HCl(aq)+ KOH(aq)→ H₂O(l)+ KCl(aq)
B)KOH(aq)→ K⁺(aq)+ OH^-(aq)
C)H₂O(l)→ H⁺(aq)+ OH^-(aq)
D)K⁺(aq)+ OH^-(aq)→ KOH(aq)
E)H⁺(aq)+ OH^-(aq)→ H₂O(l)

Question 43

In which of the following is the oxidation number for oxygen equal to zero?

A)Ca(OH)₂
B)HNO₃
C)O₂
D)H₂O₂
E)all of the above

Question 44

2 AgNO₃(aq)+ K₂SO₄(aq)→ 2 KNO₃(aq)+ Ag₂SO₄(s)
The spectator ions in the reaction shown are

A)silver ion and nitrate ion.
B)potassium ion and sulfate ion.
C)potassium ion and nitrate ion.
D)silver ion and sulfate ion.
E)hydrogen ion and hydroxide ion.

Question 45

The net ionic equation for the reaction between zinc and hydrochloric acid solution is

A)Zn(s)+ 2 H⁺(aq)→ Zn²⁺(aq)+ H₂(g).
B)Zn(s)+ 2 HCl(aq)→ ZnCl₂(aq)+ H₂(g).
C)Zn²⁺(aq)+ H₂(g)→ ZnS(s)+ 2 H⁺(aq).
D)ZnCl₂(aq)+ H₂(g)→ ZnS(s)+ 2 HCl(aq).
E)none of these

Question 46

The element chlorine is very reactive as a(an)________ agent because it readily ________ electrons to form the chloride ion.

A)oxidizing;loses
B)oxidizing;gains
C)reducing;loses
D)reducing;gains
E)none of the above

Question 47

In the following reaction which species is being oxidized and which is being reduced?
2 Cr(s)+ 3 Cl₂(g)→ 2 CrCl₃(s)

A)oxidized: Cr;reduced: CrCl₃
B)oxidized:CrCl₃;reduced: Cr
C)oxidized: Cr;reduced: Cl₂
D)oxidized: Cl₂;reduced: Cr
E)oxidized: Cl₂;reduced: CrCl₃

Question 48

2 AgNO₃(aq) + K₂SO₄ (aq) → 2 KNO₃ (aq) + Ag₂SO₄(s)
The net ionic reaction for the balanced equation shown above is

A) Ag⁺(aq)+ NO₃^-(aq)→ AgNO₃(s)
B)2 K⁺(aq)+ SO₄^2-(aq)→ K₂SO₄(aq)
C)K⁺(aq)+ NO₃^-(aq)→ KNO₃(aq)
D)2 Ag⁺(aq)+ SO₄^2-(aq)→ Ag₂SO₄(s)
E)H⁺(aq)+ OH^-(aq)→ H₂O(l)

Question 49

As a pure element the oxidation number of zinc is ________,but in compounds such as ZnCO₃ its oxidation number is ________.

A)0;0
B)0;+1
C)+1;0
D)0;+2
E)none of the above

Question 50

Which of the following is always a spectator ion in aqueous chemical reactions?

A)Na⁺
B)Cl^-
C)S^2-
D)Mg²⁺
E)all of these ions.

Question 51

In the reaction shown,________ is the oxidizing agent because it ________.
Ni(s)+ CuCl₂(aq)→ Cu(s)+ NiCl₂(aq)

A)Ni;causes reduction
B)Ni;gets reduced
C)CuCl₂;causes reduction
D)CuCl₂;gets reduced
E)NiCl₂;gets reduced

Question 52

The oxidation number of chlorine in the compound FeCl₃ is

A)-3.
B)-2.
C)-1.
D)+2.
E)+3.

Question 53

The oxidation number of iron in the compound FeBr₃ is

A)-2.
B)-1.
C)+1.
D)+2.
E)+3.

Question 54

Match the following.
LX(aq)+ MY(aq)→ LY(s)+ MX(aq)

A)redox
B)acid-base
C)precipitation

Question 55

In the redox reaction shown,________ is oxidized and becomes ________.
Fe(s)+ CuCl₂ aq)→ Cu(s)+ FeCl₂(aq)

A)Fe;Fe⁺
B)Fe;Fe²⁺
C)Cu;Cu²⁺
D)Cu²⁺;Cu
E)none of the above

Question 56

Reduction is the process of

A)gaining hydrogen.
B)losing oxygen.
C)gaining electrons.
D)forming an anion from a neutral atom.
E)all of the above

Question 57

What are the spectator ions in the reaction between KOH and HNO₃?

A)K⁺ and H⁺
B)H⁺ and OH^-
C)K⁺ and NO₃^-
D) H⁺and NO₃^-
E)none of these

Question 58

The oxidation number of sulfur in calcium sulfate,CaSO₄,is

A)+6.
B)+4.
C)+2.
D)0.
E)-2.

Question 59

When a substance loses electrons it is ________;the substance itself is acting as a(an)________ agent.

A)oxidized;oxidizing
B)oxidized;reducing
C)reduced;oxidizing
D)reduced;reducing
E)dissolved;neutralizing

Question 60

What is the oxidation number of oxygen in hydrogen peroxide,H₂O₂?

A)0
B)-1
C)-2
D)+1
E)+2

Question 61

Match the following.
HR(aq)+ XOH(aq)→ XR(aq)+ O(l)

A)redox
B)acid-base
C)precipitation