Oxidation Numbers and Ions

The video tutorial explains how to find the oxidation numbers for each element in ammonium chromate (NH4)2CrO4. It begins by identifying the compound as neutral, meaning all oxidation numbers sum to zero. The tutorial then breaks down the compound into ammonium and chromate ions. For the ammonium ion, the oxidation number of nitrogen is calculated as -3, while for the chromate ion, the oxidation number of chromium is determined to be +6. The video concludes by verifying that the sum of all oxidation numbers equals zero, confirming the compound's neutrality.

What is the overall charge of ammonium chromate?

• Variable

• Neutral

• Negative

• Positive

How many ammonium ions are present in ammonium chromate?

• Four

• One

• Two

• Three

What is the oxidation number of nitrogen in the ammonium ion?

• +3

• +1

• -3

• -1

What is the oxidation number of hydrogen when bonded to a non-metal?

• +2

• -1

• +1

• -2

What is the charge of the chromate ion?

• 1+

• 2-

• 1-

• 2+

What is the oxidation number of chromium in the chromate ion?

• +4

• -6

• +6

• -4

How many oxygen atoms are present in the chromate ion?

• Five

• Two

• Three

• Four

What is the typical oxidation number of oxygen in compounds?

• +2

• -2

• -1

• +1

Why is it important to treat ammonium and chromate as separate ions?

• To simplify calculations

• To ensure neutrality

• To identify individual oxidation numbers

• To balance the equation

What is the sum of oxidation numbers in a neutral compound?

• Zero

• One

• Two

• Three