Chapter 11: Oxidation-Reduction Reactions

Question 1

Oxidation is ________

Answer 1

loss of e-

Question 2

Reduction is ________

Answer 2

gain of e-

Question 3

An oxidizing agent causes what?

Answer 3

Causes an atom to be oxidized, and is itself reduced

Question 4

A reducing agent causes what?

Answer 4

Causes an atom to be reduced, and is itself oxidized

Question 5

Almost all oxidizing agents contain what?

Answer 5

oxygen or another strongly electronegative element

Question 6

What are some common oxidizing/reducing agents?

Answer 6

Question 7

________________ ____________ are assigned to atoms to keep track of redistribution of electrons during chemical reactions

Answer 7

Oxidation numbers

Question 8

What is the oxidation number of a free element?

Answer 8

Zero

Question 9

The oxidation number of a monatomic ion is equal to what?

Answer 9

The charge of the ion

Question 10

The oxidation number of Group VIIA is -1, except for when?

Answer 10

When combined with an element of higher electronegative.

Example: Cl- is -1 in HCl, but it is +1 in HOCl

Question 11

Hydrogen is usually ____. However, it is ____ in compounds with less electronegative elements from Groups ____ and ____.

Hydrogen is ____ in HCl, but ____ in NaH.

Answer 11

+1; -1; Groups IA and IIA
+1, -1

Question 12

In most compounds, the oxidation number of oxygen is ____. Except in peroxides (O_{2^{2-), where oxygen is ____, and compounds with more electronegative elements like OF2, where oxygen is ____.}}

Answer 12

-2; -1, +2

Question 13

The sum of oxdiation numbers in a neutral compound should be ____

Answer 13

zero

Question 14

The sum of oxidation numbers of the atoms present in a polyatomic ion is equal to ____

Answer 14

the charge of the ion

Question 15

Oxidation number assumes ________ ________ of electrons in bonds, “awarding” the electrons to the more electronegative element.

Answer 15

unequal division

Question 16

Formal charge assumes ________ ________ of electrons in bonds, awarding one electron to each atom in the bond.

Answer 16

equal division

Question 17

When assigning oxidation numbers, start with what?

Answer 17

The known atoms

Question 18

What does assigning oxidation numbers accomplish?

Answer 18

Allows us to determine how many moles of each species are required for conservation of charge and mass, which is necessary to balance the equation

Question 19

How does the half-reaction method work?

Answer 19

Separate the redox reaction into two half-reactions, the oxidation part and the reduction part, then they are balanced separately

Question 20

________________ is a specific type of redox reaction in which an element undergoes both oxidation and reduction in producing its products.

Answer 20

disproportionation

Question 21

What is an example of disproportionation?

Answer 21

catalysis of peroxides by catalase