Electrode potentials Flashcards

1
Q

How is an electrochemical cell created

A

By joining 2 different half cells together

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2
Q

With electrochemical cells, what is needed to join the 2 half cells together

A

A wire

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3
Q

In electrochemical cells what does the voltmeter measure

A

The potential difference between the 2 half cells

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4
Q

Do electrons flow from a more reactive metal to a less reactive metal, or from a less reactive metal to a more reactive metal

A

From a more reactive metal to a less reactive metal

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5
Q

What is observed when the half cell loses the electrons

A

The electrode becomes thinner

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6
Q

What time of reaction is it when the half cell loses electrons and the electrode becomes thinner

A

Oxidation

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7
Q

What type of reaction occurs when the half cell accepts electrons and the electrode gets thicker

A

Reduction

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8
Q

What is the usual compound that creates a salt bridge

A

Potassium nitrate

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9
Q

What is the electrode potential measured in

A

Volts

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10
Q

What does the electrode potential tell us

A

How easily the half cell gives up electrons

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11
Q

When writing electrochemical cell equations, in what form at the equations written

A

In reduced form, so electrons are always on the left hand side

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12
Q

When given the electrode potential values, what does the more negative value indicate( oxidation or reduction)

A

Oxidation

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13
Q

When given the electrode potential values, what does the most positive value indicate (oxidation or reduction)

A

Reduction

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14
Q

What does SHE stand for

A

Standard hydrogen electrode

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15
Q

What is the electrode potential of SHE

A

O volts

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16
Q

When setting up a SHE, what are the conditions underwhich hydrogen enters the the system

A
  • 298 K
  • 100 kPa
17
Q

What are the conditions when comparing electrode potential values

A
  • Temp: 298 K
  • Pressure: 100 kPa
  • Concentrations of ions at 1 moldm^-3
18
Q

What does the SHE allow us to find

A

The standard electrode potential of other half cells

19
Q

When given a table of standard electrode values, what is the most powerful oxidising agent

A

The most positive standard electrode value

20
Q

When given 2 equations and the electrode potential, which reaction would go forward

A

The equation with the more positive electrode potential

21
Q

What does the electrode potential say

A

How much energy is released

22
Q

When drawing electrochemical cells what are the features that you must include

A
  • 2 half cells
  • Wire
  • Voltmeter
  • Salt bridge
  • 2 Electrodes
  • The electrodes must be under the water
23
Q

If the half cell is a metal, what is the electrode made of

A

The same metal
e.g. Fe2+ +2e- -> Fe
use a Fe electrode

24
Q

If neither half cells include a metal, what electrode should you use

A
  • An inert metal like platinum
  • Or graphite
25
Q

What is the role of a salt bridge

A

Balances charges

26
Q

Does the salt bridge carry ions or electrons

A

Ions

27
Q

How do you assign the positive or negative charge to the electrode

A

The electrode that receives the electrons is the positive electrode

28
Q

When drawing an electrochemical cell, what should you draw on the wire and on the salt bridge

A

The direction the electrons/ ions flow

29
Q

What is the electrode that is used when using a hydrogen half cell

A

Platinum

30
Q

How do you use a hydrogen half cell

A

Use a platinum electrode and bubbles hydrogen gas over it using a glass tube

31
Q

What is the standard electrode potential of a half cell

A

The voltage measured in a cell in which that half cell is connected to a standard hydrogen electrode, under standard conditions