Flashcards in General Chemistry- Electrochemistry Deck (86)
What is the primary purpose of the mitochondrion?
To manufacture a deliverable and usable form of energy.
What is the average daily turnover of ATP in humans.
More than 50 kilograms
What is the voltage?
An electrical potential difference
What is the voltage called in a concentration cell?
What is the voltage called in the mitrochondria?
Proton-motive force in mitochondria
In a battery, what reaction takes place?
An oxidation reduction reaction takes place and the electrons move in the direction that causes the concentration gradient to be dissipated.
In the mitochondria, how is charge harnessed?
The charge builds up in the form of a hydrogen ion (proton) gradient between the intermembrane space and the matrix. Embedded in the iner membrane is ATP synthase, which serves a dual role as a prton channel and a catalyst for the formation of the high-energy phosphate bond in ATP, As the hydrogen ions flow down their electrochemical gradient, energy is dissipated, and this energy is harnessed by ATP synthase to form ATP
What are electrochemical cells?
Contained systems in which redox reactions occur
What are the three fundamental types of electrochemical cells?
What batteries can help understand the electrochemical cells?
Which two electrochemical cells house spontaneous reactions?
Galvanic cells and Concentration cells
Which cells house nonspontaneous reactions?
Spontaneity is indicated by the change in what?
Gibbs Free Energy
All three electrochemical cells contain what?
Electrodes where oxidation and reduction take place
For all electrochemical cells, the electrode where oxidation occurs is called what? Reduction?
What is electromotive force?
(emf) corresponds to the voltage or electrical potential difference of the cell.
If the emf is positive what does it mean for the cell? Negative?
Positive: The cell is able to release energy (/\G 0), wo it is nonspontaneous
For all electrochemical cells, the movement of electrons is from ___________ to __________.
Anode to cathode
The current runs from __________ to ________.
Cathode to anode
In chemistry current represents what?
A theoretical flow of positive charge
What are always equal in magnitude but opposite in direction?
Current and flow equal in magnitude, but opposite in direction
Can batteries and cells be influenced by temperature change?
What type of electrochemical cells are nonrechargeable batteries?
Galvanic cells, also called voltaic cells
In galvanic cells, the free energy is what?
Decreasing, as the cell reases energy to the environment
If free energy is negative then what is positive?
Their electromotive force (Ecell) must be positive. They always have opposite signs
What does the inside of a galvanic cell look like?
Two electrodes of distinct chemical identity are placed in separate compartments, which are called half-cells. The two electrodes are connected to each other by a conductive material, such as a copper wire. Along the wire, there may be other various components of a circuit, such as resistors or capacitors. Surrounding each of the electrodes is an aqueous electrolyte solution composed of cations and anions. The cations in the two half-cell colutions can be the same element as the respective metal electrode. Connecting the two solution is a structure called a salt bridge. When the electrodes are connected to each other by a conductive material, charge will begin to flow as the result of redox reaction that takes place in the two half-cells. The redox reaction in a galvanic cell is spontanteous. As the reaction procees toward equilibrium, the movement of electrons results in a conversion of electrical potential energy into kinetic energy. By separating the reduction and oxidation half-reactions, we are able to harness this energy and use it to do work by connecting various electrical devices into the circuit between the two electrodes.
What does a salt bridge consist of?
An Inert salt
What does the inner workings of a Daniell cell look like?
A zinc electrode is placed in an aqueous ZnSO4 solution and a copper electrode is placed in an aqueous CuSO4 solution. The anode of this cell is the zinc bar where Zn (s) is oxidized to Zn 2+ (aq). The cathode is the copper bar, and it is the site of the reduction of Cu 2+ (aq) to Cu (s)
What are the half-cell reactions for the Daniell cell?
Zn (s) --> Zn 2+ (aq) + 2 e- Ered= -0.762V (Anode)
Cu 2+ (aq) + 2e- --> Cu (s) Ered= +0.340V (cathode)