Electrode potentials Flashcards

1
Q

What is the salt bridge made out of?

A

Filter paper SOAKED in KNO3
(aq)

  • The salt bridge allows ions to flow through and balance out the charge
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2
Q

What is an electrochemical cell?

A

Two different metals dipped in a solution of their own ions, connected by a wire ( external circuit)

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3
Q

Electrochemical cells make electricity (practical)
zinc/copper
what happens?

A

1) Zinc loses electrons easier than copper, so zinc is oxidised to form Zn2+ (aq) ions . This releases electrons into the wire. LEFT SIDE = OXIDATION
2) In the other half cell, the same number of electrons are taken from the wire, reducing Cu2= ions into to copper atoms. RIGHT SIDE = REDUCTION

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4
Q

what does EMF stand for

A

Electromotive force

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5
Q

why are some electrodes made out of platinum

A

It is an inert metal so won’t react with the ions

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6
Q

Reactions that occur at electrochemical cells are…

A

reversible half equations

mostly reduction ( so electrons on the left side)

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7
Q

Does a metal that is easily oxidised ( easily loses electrons) have a positive or negative electrode potential?

A

Very negative electrode potential

the lower the electrode potential the easier it is to be oxidised

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8
Q

Measuring electrode potential of a half cell against standard hydrogen electrode (practical):

(ONE THING TO REMEMBER)

A
  • as cell potential is affected by (temp, pressure, conc)

- standard conditions are used.

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9
Q

Standard electrode potential of a cell def:

A

Standard electrode potential of a cell, is the voltage measured under standard conditions when the half cell is connected to a standard hydrogen electrode.

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10
Q

What are the standard conditions;

A

298K
100kpa

1moldm-3 ( any solution must have this concentration)

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