Oxidation Numbers and Reactions

The video tutorial explains the concept of oxidation numbers, which are related to the electric charge of atoms in a bond. It provides examples using oxygen and hydrogen, and discusses how oxidation and reduction processes work. The tutorial also includes a complex example from the ENEM 2014 exam, focusing on nitrogen oxidation and reduction, and explains how to determine the oxidation state in various chemical reactions.

What is the oxidation number (nox) related to?

• The number of protons in an atom

• The electric charge of an atom in a bond

• The atomic mass of an element

• The number of neutrons in an atom

How many electrons does oxygen need to gain to achieve a stable configuration?

• One

• Four

• Two

• Three

What is the oxidation number of hydrogen when it shares an electron?

• +2

• 0

• -1

• +1

In water (H2O), what is the oxidation number of oxygen?

• -1

• +2

• +1

• -2

What is the oxidation number of nitrogen in nitric acid (HNO3)?

• +3

• +4

• +5

• +6

What happens during oxidation?

• Sharing of electrons

• No change in electrons

• Gain of electrons

• Loss of electrons

What is the oxidation number of a simple substance?

• Depends on the element

• Always 0

• Always -1

• Always +1

In the ENEM 2014 example, what is the oxidation number of nitrogen in N2?

• +2

• 0

• -1

• +1

During the reduction process, what happens to the oxidation number?

• It fluctuates

• It remains the same

• It decreases

• It increases

In the ENEM 2014 example, what is the final oxidation number of nitrogen in the last step?

• +5

• +3

• -3

• 0