AP Chemistry : Thermodynamics
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Example Questions
Example Question #2 : Electrochemistry
Toward which pole do the electrons travel in an electrolytic cell?
More information is needed
Towards the cathode
Towards the anode
Towards the positive pole
The electrons do not travel; only the protons travel
Towards the cathode
Reduction always occurs at the cathode, and oxidation always occurs at the anode. Since reduction is the addition of electrons, electrons must travel toward the site of reduction.
In an electrolytic cell the negative charge is on the cathode, while the positive charge is on the anode. Since an electrolytic cell requires energy to perpetuate the reaction, we are pushing the electrons against their potential gradient. The electrons, which are negatively charged, are traveling towards the cathode, which is also negatively charged.
Example Question #1 : Help With Galvanic Cells
Which of the following differences between galvanic cells and electrolytic cells is false?
Electrolytic cells have a positive Gibb's free energy
Electrolytic cells have oxidation take place at the cathode
Electrolytic cells have negative voltages
Electrolytic cells are non-spontaneous
Electrolytic cells have oxidation take place at the cathode
Electrolytic cells use non-spontaneous reactions that require an external power source in order to proceed. The values between galvanic and electrolytic cells are opposite of one another. Galvanic cells have positive voltage potentials, while electrolytic voltage potentials are negative. Both types of cell, however, have oxidation occur at the cathode and reduction occur at the anode.
Example Question #3 : Galvanic (Voltai) And Elecrolytic Cells
What is true about the current flow in a galvanic cell?
Galvanic cells do not have a current
It travels from cathode to anode
It travels from anode to cathode
It flows in the direction of electron flow
It travels from cathode to anode
In a galvanic cell, the electrons will flow from the anode to the cathode; however, current travels in the opposite direction of the electrons by convention. In chemical cells, current is defined by the direction in which protons would flow. As a result, current flows from the cathode to the anode.
Keep in mind that reduction occurs at the cathode and oxidation occurs at the anode. Electrons are thus constantly moving from the anode to the cathode. Since the current will be opposite to the flow of electrons, we can conclude that it must flow from cathode to anode.
Example Question #4 : Galvanic (Voltai) And Elecrolytic Cells
The following galvanic cell is created:
Which of the following takes place at the cathode?
Gold loses electrons
Copper loses electrons
Gold ions receive electrons
Copper gains electrons
Gold ions receive electrons
Reduction always takes place at the cathode. This means that a substance is receiving electrons.
In the reaction, the gold ions are receiving electrons in order to create gold atoms. This takes place at the cathode.
Copper ions and gold are products, and will not be oxidized or reduced. Copper is reduced at the anode during this reaction.
Example Question #151 : Thermochemistry And Kinetics
1. 
2. 
3.
What is 
There are two concepts to consider in this problem. First, the question asks for the 
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