redox

What reaction occurs at the anode?

• Ag⁺ + e^- →Ag
• Ag → Ag⁺ + e^-
• Ni²⁺ + 2e^- → Ni
• Ni → Ni²⁺ + 2e^-

This electrode loses mass 

• anode
• cathode

Reduction happens at the 

• anode
• cathode
• salt bridge
• voltmeter

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⁺

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

• Oxidized
• Reduced

In a voltaic cell the ions flow through the 

• wire
• salt bridge

In a voltaic cell electrons flow

• through the salt bridge
• from the cathode to the anode through the wire
• from the anode to the cathode through the wire

Which of the following reactions is balanced by both mass and charge?

• Fe⁺² + Al →Fe + Al⁺³
• Cu + Fe⁺² → Cu⁺¹ + Fe⁺³
• F₂ + Br^- --> F^- + Br₂
• Fe⁺² + 2 Cu --> 2 Cu⁺ + Fe

Oxygen always has an oxidation number of...

• -1
• 1
• 2
• -2

Which energy conversion shown below takes place in a voltaic cell?

• Electrical to chemical

• Mechanical to chemical

• Mechanical to electrical

• Chemical to electrical