19.2.2 Electromotive Force Flashcards
1
Q
Electromotive Force
A
- Electrical potential is a measure of the work that could be performed by a moving charge.
- The electromotive force (E cell , emf, or ΔE ̊) is a measure of the driving force on electrons to move through a circuit.
2
Q
note
A
- Electrical potential is a measure of the work that could be performed by a moving charge (such as an electron).
- The difference in electrical potential between two points is called the potential difference (ΔE). The potential difference is measured in volts (V).
- The maximum potential difference in an electrochemical cell is the electromotive force (E cell , emf, or ΔE ̊).
- The electromotive force is analogous to water pressure. The pressure on water flowing from a tank at the top of a hill depends on the difference in height between the spout and the tank, but not on the amount of water in the tank. Similarly, the pressure on electrons flowing through a circuit (the electromotive force) depends on the potential difference, but not on the number of electrons involved in the reaction.
- The flow of water is measured in gallons per minute (amount of water per time). Similarly, the flow of electrons is measured in coulombs per second (amount of charge per time).
3
Q
Why must the switch be open to measure EMF?
A
Because of resistance in the cell
4
Q
Examine the cell shown in the figure. Would the meter indicate that the cell had a voltage? If not, why not?
A
Yes, there would be a voltage.
5
Q
What is cell potential?
A
The difference in electrical potential energy between the two electrodes of a galvanic cell.
6
Q
Which unit is used to measure electromotive force(EMF)?
A
volts
7
Q
Which of the following can be done to make a cell with a higher EMF?
A
Use different metals
8
Q
Which of the following statements is not correct?
A
In order for a reaction to be spontaneous, the electrode potentials must be equal.
9
Q
What is a volt?
A
joule per coulomb
