Deck 10: Electron Transfer in Chemical Reactions

Question 1

What is the oxidation state of manganese in the compound KMnO₄?

A) +4
B) +2
C) +7
D) -4

Answer 1

+7

Question 2

Which of the following does not have the same number of electrons when compared with the rest?

A) Mg²⁺
B) O^₂-
C) F
D) Ne

Answer 2

F

Question 3

What is the oxidation state of chromium in the compound K₂Cr₂O₇?

A) +4
B) +6
C) +7
D) -1

Answer 3

+6

Question 4

Which atom in the compound KClO₃ has a negative oxidation state?

A) potassium
B) oxygen
C) both potassium and chlorine
D) both chlorine and oxygen

Question 5

Which of the following elements may have +4 charge?

A) magnesium
B) aluminum
C) carbon
D) chlorine

Question 6

What is the oxidation state of the carbon atom in the compound CO₂?

A) +2
B) +3
C) +4
D) -2

Question 7

What is electricity?

A) flow of atoms
B) flow of protons
C) flow of neutrons
D) flow of electrons

Question 8

In a chemical bond, which atom gets ownership the shared electrons?

A) the larger element
B) the smaller element
C) the more electronegative element
D) the most electropositive element

Question 9

In which case is chlorine in its highest oxidation state?

A) sodium hypochlorite
B) sodium chloride
C) sodium perchlorate
D) sodium chlorate

Question 10

Which of the following elements may have an oxidation number other than +2?

A) magnesium
B) calcium
C) barium
D) iron

Question 11

Which atom in the compound K₂C₂O₄ has a positive oxidation state?

A) potassium
B) carbon
C) both potassium and carbon
D) both potassium and oxygen

Question 12

Which of the following elements may have a +3 charge when it becomes an ion?

A) magnesium
B) aluminum
C) carbon
D) chlorine

Question 13

Which of the following elements may not have an oxidation number of -1?

A) chlorine
B) hydrogen
C) sodium
D) fluorine

Question 14

Which of the following elements may have more than one oxidation number?

A) hydrogen
B) sodium
C) calcium
D) lithium

Question 15

Which atom(s) has a more positive oxidation state on the product side than the reactant side? Fe₂O₃ + 3CO → 2Fe + 3CO₂

A) iron
B) oxygen
C) carbon
D) carbon and iron

Question 16

Which of the following has 8 electrons in the outer shell?

A) Ca^₂+
B) Cl+
C) S²⁺
D) Fe^₃+

Question 17

What is the oxidation state of the nitrogen atom in the compound NCL₃?

A) 0
B) +3
C) +5
D) -3

Question 18

Which of the following elements may have an oxidation number of +1 or -1?

A) hydrogen
B) sodium
C) potassium
D) lithium

Question 19

In the water molecule, which atom holds the shared electrons between hydrogen and oxygen?

A) oxygen
B) hydrogen
C) both are shared equally
D) One cannot say unless the state of water is known.

Question 20

Which atom(s) has a more negative oxidation state on the product side than the reactant side? Fe₂O₃ + 3CO → 2Fe + 3CO₂

A) iron
B) oxygen
C) carbon
D) carbon and oxygen

Question 21

Halogens most often have an oxidation state of ________.

A) +1
B) -1
C) +7
D) -3

Question 22

The overall charge of sodium dichromate is ________.

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

Question 23

The oxidizing agent is ________.

A) reduced in a redox equation
B) oxidized in a redox equation
C) reduced in an oxidation reaction
D) oxidized in a reduction reaction

Question 24

The reducing agent is ________.

A) reduced in a redox equation
B) oxidized in a redox equation
C) reduced in an oxidation reaction
D) oxidized in a reduction reaction

Question 25

In which of the following is oxygen not at the -2 oxidation state?

A) water
B) methanol
C) hydrogen peroxide
D) carbon dioxide

Question 26

The oxidation state of chlorine in the perchlorate ion is ________.

A) +8
B) +7
C) -1
D) +6

Question 27

Which of the following is true for the following reaction? Mg + O₂ → 2 MgO

A) Magnesium is oxidized.
B) The oxidation state of magnesium in MgO is +2.
C) Oxygen is reduced.
D) All of the above are true.

Question 28

Identify the reducing agent in the following chemical process (a lead storage battery). Pb + PbO₂ + 2H+ + 2HSO₄- → 2PbSO₄ + 2H₂O

A) PbO₂
B) Pb
C) H+
D) 2HSO^₄-

Question 29

The oxidation state of oxygen gas is ________.

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

Question 30

The oxidation state of sulfur in the sulfate ion is ________.

A) +6
B) +7
C) -2
D) +4

Question 31

The only element that is more electronegative than oxygen is ________.

A) chlorine
B) fluorine
C) nitrogen
D) sulfur

Question 32

What is the sum of the oxidation states in the following species H₂SbO₃-?

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

Question 33

Identify the compound that contains bromine with a +3 oxidation state.

A) NaBrO₂
B) NaBrO₃
C) NaBrO
D) NaBrO₄

Question 34

Which of the following is true for the following reaction? Cu + ZnCL₂ → CuCL₂ + Zn

A) Cu is oxidized.
B) Cu is a reducing agent.
C) Zn+2 is reduced.
D) All of the above statements are correct.

Question 35

What is oxidation?

A) loss of electrons
B) increase in oxidation number
C) gain of electrons
D) two of the above

Question 36

The oxidation state of chlorine in sodium perchlorate is ________.

A) -1
B) +1
C) +3
D) +7

Question 37

What is reduction?

A) loss of electrons
B) increase in oxidation number
C) gain of electrons
D) two of the above

Question 38

The oxidation state of nitrogen in the ammonium ion is ________.

A) +3
B) +1
C) -3
D) -1

Question 39

Which of the following is true for the following reaction? Zn + CuCL₂ → ZnCL₂ + Cu

A) The solution will turn blue.
B) The solution will turn from blue to light blue.
C) The gray zinc powder will disappear.
D) Both B and C are correct.

Question 40

The oxidation state of phosphorus in P4 is ________.

A) +4
B) +3
C) -3
D) 0

Question 41

Identify the oxidizing agent. I₂ + 6 H₂O + 5 CL₂ → 2HIO₃ + 10 HCl

A) I₂
B) H₂O
C) CL₂
D) the oxygen in water

Question 42

Identify the element that was reduced. H₂SO₄ + Al(OH)3 → AL₂(SO₄)3 + H₂O

A) aluminum
B) sulfur
C) oxygen
D) No elements were either oxidized or reduced.

Question 43

The following reaction is an example of a ________ battery. Zn + Cu⁺² → Zn⁺² + Cu

A) zinc-copper
B) copper-zinc
C) copper-silver
D) copper-zinc--hydrogen

Question 44

Identify the element that was oxidized. H₂O + CO₂ → H₂CO₃

A) carbon
B) oxygen
C) hydrogen
D) None of the elements were oxidized.

Question 45

Consult the EMF activity series and predict which of the following changes will occur if an iron nail is placed in an aqueous solution containing the (SN₂+) ion.

A) Nothing at all will happen (no reaction).
B) Tin will be further oxidized.
C) Iron will be reduced.
D) Iron will be oxidized.

Question 46

Identify the oxidized species in the following chemical process. Fe + Cu(NO₃)2 → Fe(NO₃)2 + Cu

A) Fe
B) Cu⁺²
C) NO^₃-
D) Cu

Question 47

Identify the equation that has the least number of electrons transferred

A) NaClO → NaClO₂
B) 2 Mg + O₂ → 2 MgO
C) CuCl → CuCL₂
D) NaClO₂ → NaClO₄

Question 48

Which of the following is the most easily reduced?

A) K+
B) Na+
C) Au+
D) Hg²⁺

Question 49

Identify the reduced species in the following chemical process (a lead storage battery). Pb + PbO₂ + 2H+ + 2HSO₄- → 2PbSO₄ + 2H₂O.

A) PbO₂
B) Pb
C) H+
D) 2HSO^₄-

Question 50

Identify the reduced species in the following chemical process. Cu + 2AgCl → CuCl₂ + 2Ag

A) Ag
B) Ag+
C) Cl-
D) Cu

Question 51

A fuel cell is essentially a battery which uses the following reaction to produce electricity. What is happening at the cathode of such a fuel cell? 2H₂ + O₂ → 2H₂O

A) Hydrogen is being oxidized.
B) Oxygen is being oxidized.
C) Nothing at all is happening there.
D) Oxygen is being reduced.

Question 52

Identify the oxidizing agent in the following chemical process. Fe + Cu(NO₃)2 → Fe(NO₃)2 + Cu

A) Fe
B) Cu⁺²
C) NO^₃-
D) Cu

Question 53

Identify the reducing agent in the following chemical process. Cu + 2AgCl → CuCl₂ + 2Ag

A) Ag
B) Ag+
C) Cl-
D) Cu

Question 54

Identify the oxidation-reduction equation.

A) NaOH + HCl → NaCl + H₂O
B) AgNO₃ + NaCl → AgCl + NaNO₃
C) CH₄ + 2 O₂ → CO₂ + 2 H₂O
D) CaO + CO₂ → CaCO₃

Question 55

The reactants in a dry cell are ________.

A) Cu⁺² and Zn
B) Zn⁺² and Cu
C) Zn and MnO₂
D) Zn⁺² and Al

Question 56

Which of the following is the most easily reduced?

A) MN^₂+
B) Fe²⁺
C) ZN^₂+
D) Cu²⁺

Question 57

Consult the EMF activity series and predict which of the following changes will occur if an 24K gold ring (pure gold) is placed in an aqueous solution containing hydrochloric acid.

A) Nothing at all will happen (no reaction).
B) Hydrogen will be further oxidized.
C) Gold will be reduced.
D) Gold will be oxidized.

Question 58

Identify the equation that has the greatest number of electrons transferred.

A) NaClO → NaClO₂
B) 2 Mg + O₂ → 2 MgO
C) CuCl → CuCL₂
D) NaClO₂ → NaClO₄

Question 59

Identify the element that was oxidized. 3 P + 5 HNO₃ + 2 H₂O → 5 NO + 3 H₃PO₄

A) phosphorus
B) nitrogen
C) oxygen
D) No elements were either oxidized or reduced.

Question 60

What chemical process is happening at the anode of a fuel cell, which uses the following reaction to generate electricity? 2H₂ + O₂ → 2H₂O

A) Hydrogen is being oxidized.
B) Oxygen is being oxidized.
C) Nothing at all is happening there.
D) Oxygen is being reduced.

Question 61

In a chemical bond the less electronegative element gets complete ownership of both the shared electrons.

Question 62

In Mg2+ the magnesium ion has 10 electrons.

Question 63

All four halogens, F, Cl, Br and I, are diatomic in their free state.

Question 64

Electricity is the flow of electrons.

Question 65

In S^2- the sulfur anion has 16 electrons.

Question 66

The oxidation state of an atom in its natural occurring elemental form is always equal to zero.

Question 67

The lowest oxidation state sulfur can have is in the sulfite form.

Question 68

The sum of the oxidation states of all atoms in a formula must add up to the overall charge of the formula.

Question 69

The oxygen anion almost always has the charge of -2.

Question 70

Which of the following is most easily oxidized?

A) Ni
B) Pb
C) Li
D) Cr

Question 71

In a chemical reaction the easiest electrons to be transferred are the core electrons (also called inner shell electrons).

Question 72

Which of the following is most easily oxidized?

A) Fe
B) Al
C) Cu
D) Au

Question 73

Which of the following reactions is a combustion reaction?

A) NaOH + HCl → NaCl + H₂O
B) AgNO₃ + NaCl → AgCl + NaNO₃
C) CH₄ + 2 O₂ → CO₂ + 2 H₂O
D) CaO + CO₂ → CaCO₃

Question 74

Which of the following reactions is not an oxidation-reduction reaction?

A) 2 Na + H₂O → 2 NaOH + H₂
B) Mg + 2 HCl → MgCL₂ + H₂
C) CH₄ + 2 O₂ → CO₂ + 2 H₂O
D) CaO + CO₂ → CaCO₃

Question 75

The overall charge of calcium sulfate is -2.

Question 76

The highest oxidation state that sulfur can have is +6.

Question 77

The only tetraatomic element is sulfur.

Question 78

When drawing dot structures, lone pairs of electrons are assigned completely to the atom on which they are drawn on the dot diagram.

Question 79

The equation for rust formation is ________.

A) 4 Fe + 3 O₂ + 2 H₂O → 2 Fe₂O₃ + H₂O
B) 2 Fe + O₂ → 2 FeO
C) MnO₂ + 2 Fe → Mn + 2 FeO
D) CuO + Fe → Cu + FeO

Question 80

Ca^₂+, K+ and Cl- have the same number of electrons.