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Flashcards in General Chemistry- Electrochemistry Deck (86)
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1

What is the primary purpose of the mitochondrion?

To manufacture a deliverable and usable form of energy.

2

What is the average daily turnover of ATP in humans.

More than 50 kilograms

3

What is the voltage?

An electrical potential difference

4

What is the voltage called in a concentration cell?

Electromotive force

5

What is the voltage called in the mitrochondria?

Proton-motive force in mitochondria

6

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.

7

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

8

What are electrochemical cells?

Contained systems in which redox reactions occur

9

What are the three fundamental types of electrochemical cells?

Galvanic ccells
Electrolytic cells
Concentration cells

10

What batteries can help understand the electrochemical cells?

Ni-Cd batteries

11

Which two electrochemical cells house spontaneous reactions?

Galvanic cells and Concentration cells

12

Which cells house nonspontaneous reactions?

Electrolytic cells

13

Spontaneity is indicated by the change in what?

Gibbs Free Energy

14

All three electrochemical cells contain what?

Electrodes where oxidation and reduction take place

15

For all electrochemical cells, the electrode where oxidation occurs is called what? Reduction?

Oxidation: Anode
Reduction: Cathode

16

What is electromotive force?

(emf) corresponds to the voltage or electrical potential difference of the cell.

17

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

18

For all electrochemical cells, the movement of electrons is from ___________ to __________.

Anode to cathode

19

The current runs from __________ to ________.

Cathode to anode

20

In chemistry current represents what?

A theoretical flow of positive charge

21

What are always equal in magnitude but opposite in direction?

Current and flow equal in magnitude, but opposite in direction

22

Can batteries and cells be influenced by temperature change?

Yes

23

What type of electrochemical cells are nonrechargeable batteries?

Galvanic cells, also called voltaic cells

24

In galvanic cells, the free energy is what?

Decreasing, as the cell reases energy to the environment

25

If free energy is negative then what is positive?

Their electromotive force (Ecell) must be positive. They always have opposite signs

26

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.

27

What does a salt bridge consist of?

An Inert salt

28

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)

29

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)

30

What is the net reaction of a Daniell cell?

Zn (s) + Cu 2+ (aq) --> Zn 2+ (aq) + Cu (s) Ecell=+1.102V