Name: 
 

Ch 20 Redox Formative Test


Matching
 
 
Match each item with the correct statement below.
a.
oxidation number
c.
oxidizing agent
b.
half-reaction
d.
reducing agent
 

 1. 

 substance that accepts electrons
 

 2. 

 substance that donates electrons
 

 3. 

 integer related to the number of electrons under an atom's control
 

 4. 

 reaction showing either the reduction or the oxidation reaction
 
 
Match each item with the correct statement below.
a.
Choose coefficients to make the change in oxidation number equal to 0.
b.
Make the electron changes of both half-reactions equal.
c.
Assign oxidation numbers to all the atoms.
d.
Write the equation showing ions separately.
 

 5. 

 the first step in balancing a redox reaction by the oxidation-number-change method
 

 6. 

 the next-to-the-last step in balancing a redox reaction by the oxidation-number-change method
 

 7. 

 the first step in balancing a redox reaction by the half-reaction method
 

 8. 

 the next-to-the-last step in balancing a redox reaction by the half-reaction method
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 9. 
If an atom is reduced in a redox reaction, what must happen to another atom in the system?
a.
It must be oxidized.
b.
It must be reduced.
c.
It must be neutralized.
d.
Nothing needs to happen to another atom in the system.
 

 10. 
What is another name for an oxidation-reduction reaction?
a.
O-reaction
c.
redox reaction
b.
R-reaction
d.
oxred reaction
 

 11. 
When iron oxide becomes iron, what type of reaction occurs?
a.
oxidation
c.
neutralization
b.
reduction
d.
combination
 

 12. 
In which of the following types of reaction are electrons gained?
a.
decomposition
c.
neutralization
b.
oxidation
d.
reduction
 

 13. 
Oxidation is ____.
a.
a loss of oxygen
c.
a loss of electrons
b.
a gain of electrons
d.
a gain of hydrogen
 

 14. 
What are transferred in an oxidation-reduction reaction?
a.
protons
c.
electrons
b.
ions
d.
atoms
 

 15. 
In the reaction of sodium with oxygen, which atom is reduced?
a.
sodium
c.
both a and b
b.
oxygen
d.
neither a nor b
 

 16. 
In the reaction of sodium with oxygen, which atom is the reducing agent?
a.
sodium
c.
both a and b
b.
oxygen
d.
neither a nor b
 

 17. 
In the reaction of calcium with chlorine, which atom is the oxidizing agent?
a.
calcium
c.
both a and b
b.
chlorine
d.
neither a nor b
 

 18. 
In the reaction of calcium with chlorine, which atom is oxidized?
a.
calcium
c.
both a and b
b.
chlorine
d.
neither a nor b
 

 19. 
In the reaction of hydrogen with iodine, which atom is oxidized?
a.
hydrogen
c.
both a and b
b.
iodine
d.
neither a nor b
 

 20. 
In the reaction of hydrogen with iodine, which atom is the reducing agent?
a.
hydrogen
c.
both a and b
b.
iodine
d.
neither a nor b
 

 21. 
Cumc021-1.jpg ® Cumc021-2.jpg + 2 e-
The equation above represents the type of reaction called ____.
a.
redox
c.
reduction
b.
hydrolysis
d.
oxidation
 

 22. 
Which type of reaction does Snmc022-1.jpg ® Snmc022-2.jpg represent?
a.
oxidation
c.
hydrolysis
b.
reduction
d.
none of the above
 

 23. 
What is the reducing agent in the following reaction?
2Na + 2Hmc023-1.jpgO ® 2NaOH + Hmc023-2.jpg
a.
Na
c.
NaOH
b.
Hmc023-3.jpgO
d.
Hmc023-4.jpg
 

 24. 
What is the reducing agent in the following reaction?
2Na + S ® Namc024-1.jpgS
a.
Na
c.
Namc024-2.jpgS
b.
S
d.
Namc024-3.jpg
 

 25. 
What is the oxidizing agent in the following reaction?
CHmc025-1.jpg + 2Omc025-2.jpg mc025-3.jpg COmc025-4.jpg + Hmc025-5.jpgO
a.
CHmc025-6.jpg
c.
COmc025-8.jpg
b.
Omc025-7.jpg
d.
Hmc025-9.jpgO
 

 26. 
Which statement is true about the following reaction?
S + Clmc026-1.jpg mc026-2.jpg SClmc026-3.jpg
(Hint: Chlorine is the more electronegative element.)
a.
Sulfur is reduced to SClmc026-4.jpg.
c.
Chlorine is oxidized to SClmc026-6.jpg.
b.
Chlorine is reduced to SClmc026-5.jpg.
d.
Sulfur is the oxidizing agent.
 

 27. 
What is the oxidizing agent in the following reaction?
Imc027-1.jpg + MnOmc027-2.jpgmc027-3.jpg mc027-4.jpg Imc027-5.jpg + MnOmc027-6.jpg
a.
Imc027-7.jpg
c.
Imc027-10.jpg
b.
MnOmc027-8.jpgmc027-9.jpg
d.
MnOmc027-11.jpg
 

 28. 
Why is oxygen reduced in the reaction of hydrogen with oxygen to make water?
a.
Oxygen pulls electrons toward itself.
b.
Oxygen pushes electrons toward the hydrogens.
c.
Oxygen absorbs a proton.
d.
Oxygen releases a proton.
 

 29. 
The oxidation number of magnesium in magnesium chloride is ____.
a.
–1
c.
+1
b.
0
d.
+2
 

 30. 
The oxidation number of hydrogen when it is in a compound other than a hydride is ____.
a.
–2
c.
0
b.
–1
d.
+1
 

 31. 
The oxidation number of bromime in bromime gas is ____.
a.
–2
c.
0
b.
–1
d.
+1
 

 32. 
What is the oxidation number for each atom in NHmc032-1.jpgCl?
a.
N = +3, H = –4, Cl = +1
c.
N = +3, H = +1, Cl = –1
b.
N = –3, H = +1, Cl = –1
d.
N = –3, H = –1, Cl = +1
 

 33. 
What is defined as the charge an atom would have in a compound if its bonding electrons were assigned to the more electronegative atom?
a.
reduction number
c.
valence
b.
oxidation number
d.
electropositivity
 

 34. 
The oxidation number of sulfur in each of the following is +6 EXCEPT for ____.
a.
SOmc034-1.jpg
c.
SOmc034-4.jpgmc034-5.jpg
b.
Namc034-2.jpgSOmc034-3.jpg
d.
Smc034-6.jpgOmc034-7.jpgmc034-8.jpg
 

 35. 
In which of the following compounds is the oxidation number of nitrogen different from the other three?
a.
NOmc035-1.jpgmc035-2.jpg
c.
NHmc035-5.jpgCl
b.
Nmc035-3.jpgOmc035-4.jpg
d.
Ca(NOmc035-6.jpg)mc035-7.jpg
 

 36. 
Identify the atom that increases in oxidation number in the following redox reaction.
2MnOmc036-1.jpg + 2Kmc036-2.jpgCOmc036-3.jpg + Omc036-4.jpg mc036-5.jpg 2KMnOmc036-6.jpg + 2COmc036-7.jpg
a.
Mn
c.
K
b.
O
d.
C
 

 37. 
Which atom has a change in oxidation number of –3 in the following redox reaction?
Kmc037-1.jpgCrmc037-2.jpgOmc037-3.jpg + Hmc037-4.jpgO + S mc037-5.jpg KOH + Crmc037-6.jpgOmc037-7.jpg + SOmc037-8.jpg
a.
K
c.
O
b.
Cr
d.
S
 

 38. 
In the following unbalanced reaction, which atom is reduced?
Hmc038-1.jpgO + Clmc038-2.jpg + SOmc038-3.jpg mc038-4.jpg HCl + Hmc038-5.jpgSOmc038-6.jpg
a.
hydrogen
c.
chlorine
b.
oxygen
d.
sulfur
 

 39. 
In the following unbalanced reaction, which atom is oxidized?
HNOmc039-1.jpg + HBr mc039-2.jpg NO + Brmc039-3.jpg + Hmc039-4.jpgO
a.
hydrogen
c.
oxygen
b.
nitrogen
d.
bromine
 

 40. 
Which element decreases its oxidation number in the following reaction?
BiClmc040-1.jpg + Namc040-2.jpgSOmc040-3.jpg mc040-4.jpg 2NaCl + BiSOmc040-5.jpg
a.
bismuth
b.
chlorine
c.
oxygen
d.
No element decreases its oxidation number.
 

 41. 
Which element increases its oxidation number in the following reaction?
3KOH + Hmc041-1.jpgPOmc041-2.jpg mc041-3.jpg Kmc041-4.jpgPOmc041-5.jpg + 3Hmc041-6.jpgO
a.
potassium
b.
hydrogen
c.
oxygen
d.
No element increases its oxidation number.
 

 42. 
Which element decreases its oxidation number in the following reaction?
Imc042-1.jpg + 2KCl mc042-2.jpg 2KI + Clmc042-3.jpg
a.
iodine
b.
potassium
c.
chlorine
d.
No element decreases its oxidation number.
 

 43. 
Which element increases its oxidation number in the following reaction?
2Na + 2Hmc043-1.jpgO mc043-2.jpg 2NaOH + Hmc043-3.jpg
a.
sodium
b.
hydrogen
c.
oxygen
d.
No element increases its oxidation number.
 

 44. 
Which of the following reactions is a redox reaction?
a.
acid-base
c.
combustion
b.
double-replacement
d.
all of the above
 

Numeric Response
 

 45. 
What is the oxidation number of magnesium in magnesium iodide?

 

 46. 
What is the sum of the oxidation numbers in lithium carbonate?

 

 47. 
What is the sum of the oxidation numbers in calcium carbonate?

 

 48. 
What is the sum of the oxidation numbers in the chlorate ion?

 



 
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