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

• -2
• +2
• +6
• +12

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What element always has an oxidation number of -1?

• Hydrogen
• Fluorine
• Chlorine
• Iodine

     In the reaction Zn + H₂O --> ZnO₂ + H₂
 which element, if any, is oxidized? 

• Zinc
• Hydrogen
• Oxygen
• None

Tags

NGSS.HS-PS1-2

Another name for a "oxidation-reduction" reaction is

• chemical reaction
• neutralization reaction
• redox reaction
• nuclear reaction

Which of the following is the balanced half -reaction for the oxidation of Cu to Cu^+2?

• Cu   --> Cu⁺²
• Cu + 2 e-   --> Cu⁺²
• Cu  --> Cu⁺²  + 2 e-
• Cu - 2e-  --> Cu⁺²

Tags

NGSS.HS-PS1-7

     In the reaction Zn + H₂O → ZnO₂ + H₂
 which element, if any, is oxidized?

• Zinc
• Hydrogen
• Oxygen
• None

Which are examples of reduction?

• I and II
• I and III
• II and III
• I, II and III

Tags

NGSS.HS-PS1-2

Which change does nitrogen undergo oxidation?

• A
• B
• C
• D

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What happens to Cr³⁺ ion when it is converted to CrO₄^2–

• Oxidation number decreases and it undergo reduction
• Oxidation number decreases and it undergo oxidation
• Oxidation number increases and it undergo reduction
• Oxidation number increases and it undergo oxidation

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What happens to iodine when iodate, IO₃^–, converted to iodine, I₂?

• Undergo reduction and oxidation number changes from –1 to 0
• Undergo oxidation and oxidation number changes from –1 to 0
• Undergo reduction and oxidation number change from +5 to 0
• Undergo oxidation and oxidation number change from +5 to 0

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7