Kw (Ionic Product Of Water Constant) Flashcards

1
Q

What is the ionic product of water constant?

A

A type of equilibrium constant used for the dissociation of H2O molecules into H3O+ and OH-

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2
Q

How do we obtain the expression of Kw?

A

Kc =[H+] [OH-] / [H2O]
Multiply both sides by H2O
Kc x H2O = [OH-] [H+]
Kw is Kc x H2O
So Kw = [OH-] [H+]

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3
Q

What reaction do we use to find Kw?

A

H2O <——> OH- + H+

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4
Q

How does dissociation of water like this occur?

A

Anywhere where water is because water can act as a base or acid
1 water molecule acts as base and accepts H+ to form H3O+
1 water molecule acts as acid and donates H+ to leave behind OH-

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5
Q

Why is [H2O] not included in expression for Kw?

A

Such little water is actually dissociated so it remains same: forms part of the constant because it remains constant

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6
Q

Kw is constant at…

A

1 temperature

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7
Q

Units of Kw

A

Mol² dm⁻⁶

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8
Q

Pure water means…

A

[H+] = [OH-]

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