Oxidation Numbers

The sum of all oxidation numbers in a neutral compound is ___.

• 0
• 1
• -1
• depends on the compound

What is oxidation number of Cr in Cr₂O_7^2-?

• -2
• +2
• +6
• +12

What is oxidation number of Na in Na⁺ ?

• 0
• +1/2
• +1
• -1

What is oxidation number of P in K₃PO₄?

• +1
• +5
• -2
• 0

What is oxidation number of H in CaH₂?

• +1
• -1
• 0
• +2

What is oxidation number of O in O₂ ?

• 0
• -2
• +1
• +2

What is oxidation number of Fe in FeO ?

• +2
• -2
• 0
• +1

Tags

NGSS.HS-PS1-2

Is calcium oxidized or reduced in the following reaction? 
2CaO --> 2Ca + O₂

• Oxidized
• Reduced

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-1

If an element loses electrons during a chemical reaction, the element was

• Oxidized
• Reduced
• Neutralized
• Precipitated

What substance is oxidized in the following reaction?
4Fe + 3O₂ --> 2Fe₂O₃

• Iron
• Oxygen