Deck 5: Classification and Balancing of Chemical Reactions

Question 1

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).

Answer 1

2 NaCl (aq)could also be correctly written as Na₂Cl₂ (aq).

Question 2

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

Answer 2

5

Question 3

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

Answer 3

1,1,1,1

Question 4

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 5

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

Question 6

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 7

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

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

Question 8

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 9

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 10

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 11

In a chemical reaction

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

Question 12

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 13

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 + C (s)→ 6 Fe (l)+ CO₂ (g).
B)2 FeO₃ + 3 C (s)→ 2 Fe (l)+ 3 CO₂ (g).
C)4 Fe₂O₃ + 6 C (s)→ 8 Fe (l)+ 6 CO₂ (g).
D)2 FeO + C (s)→ 2 Fe (l)+ CO₂ (g).
E)2 Fe₂O₃ + 3 C (s)→ 4 Fe (l)+ 3 CO₂ (g).

Question 14

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 15

Which statement regarding balanced chemical equations is not true?

A)The number of each kind of atoms 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.

Question 16

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 17

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

Question 18

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 19

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 20

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 21

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 22

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 23

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 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 O₂ (g)

Question 25

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 26

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

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

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

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 29

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 30

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 31

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 32

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 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

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)both A and B

Question 35

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 36

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 37

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 38

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 39

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

Question 40

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 41

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

A)redox
B)acid-base
C)precipitation

Question 42

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^-

Question 43

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 44

Match the following.
M (s)+ 2 LX (aq)→ 2 L (s)+ MX₂ (aq)

A)redox
B)acid-base
C)precipitation

Question 45

Match the following.
HR (aq)+ XOH (aq)→ XR (aq)+ H₂O (l)

A)redox
B)acid-base
C)precipitation

Question 46

2 AgNO₃ (aq)+ K₂SO₄(aq)→ 2 KNO₃ (aq)+ Ag₂SO₄s)
The net ionic reaction for the balanced equation shown above is

A)Ag⁺ +

→ AgNO₃.
B)2 K⁺ +

→ K₂SO₄.
C)K⁺ +

→ KNO₃.
D)2 Ag⁺ +

→ Ag₂SO₄.
E)H⁺ + OH^- → H₂O.

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

Question 48

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 49

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

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

Question 50

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

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

Question 51

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 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