Redox Reactions

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

• Oxidized
• Reduced

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following half reactions correctly represents a reduction half reaction?

• Fe →Fe²⁺ + 2e^-
• Pb⁴⁺ + 2e^- →Pb²⁺
• 2O^-2 →O₂ + 4e^-
• Fe + 3e^- →Fe³⁺

Tags

NGSS.HS-PS1-7

Reduction is the ___________ of electrons.

• loss

• gain

• sharing

• transfer

Tags

NGSS.HS-PS1-7

Which of the following represents oxidation?

• C → CH₄

• Fe³⁺ → Fe²⁺

• Cl₂ → 2Cl^-

• Zn → ZnO

In the reaction Zn + 2HCl --> ZnCl₂ + H₂

which element, if any, is oxidized?

• Zinc

• Hydrogen

• Chlorine

• None

Which statement is true:
Mg → Mg²⁺ + 2e^–

• Mg gains 2 electrons
• Mg_²⁺ loses 2 electrons
• Mg loses 1 electron
• Mg loses 2 electrons

Tags

NGSS.HS-PS1-2

The following chemical equation represents the extraction of silicon from quartz using coke.

SiO₂ + C → Si + CO₂

What is the change in oxidation number of silicon?

• +2 to 0

• +4 to 0

• 0 to +2

• 0 to +4

charge on cation is

Which of the following cannot occur during oxidation?

• Gain of oxygen

• Donation of electrons

• Loss of hydrogen

• Decrease in oxidation number

• -2

• 0

• -1

• +1