Oxidation Numbers and Cobalt Compounds

The video tutorial explains how to calculate the oxidation number for cobalt in cobalt(II) chloride (CoCl2). It begins by clarifying common misconceptions about the compound's notation. The tutorial then demonstrates the calculation process, showing that chlorine has an oxidation number of -1, and since there are two chlorine atoms, their total is -2. To balance this, cobalt must have an oxidation number of +2. An algebraic method is also presented to verify the result. The video concludes by reiterating the oxidation number of cobalt and thanking viewers.

What is the chemical formula for cobalt(II) chloride?

• CoCl3

• Co2Cl

• Co2Cl3

• CoCl2

What is the typical oxidation number for chlorine in compounds?

• 0

• +2

• -1

• +1

How many chlorine atoms are present in CoCl2?

• 1

• 2

• 3

• 4

What is the total oxidation number contributed by the chlorine atoms in CoCl2?

• -3

• -4

• -2

• -1

What algebraic symbol is used to represent the unknown oxidation number of cobalt?

• a

• x

• z

• y

What is the oxidation number of cobalt in CoCl2?

• +1

• +3

• +2

• +4

Why is cobalt in CoCl2 referred to as cobalt(II)?

• Because it has two chlorine atoms

• Because it forms two types of compounds

• Because it is the second most common form

• Because it has an oxidation number of +2