Chapter 20 - Acids, Bases and pH Flashcards

1
Q

What is a Brønsted-Lowry acid?

A

Proton donor (often +ve ion)

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2
Q

What is a Brønsted-Lowry base?

A

Proton acceptor (often -ve ion)

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3
Q

What is a conjugate-acid-base pair?

A

Contains two species that can be interconnected by transfer of a proton

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4
Q

What is the formula and charge of a hydronium ion?

A

H3O+

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5
Q

What is a monobasic acid?

A

ONE hydrogen atom replaced in acid

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6
Q

What is dibasic acid?

A

TWO hydrogen atoms replaced in acid

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7
Q

What is tribasic acid?

A

THREE hydrogen atoms replaced in acid

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8
Q

How to find the volume of base that will neutralise an acid depending on whether it is mono-, di-, or tri- basic?

A

Multiply known volume of acid by factors x1 or x2 or x3 (respectively)

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9
Q

Formula to find out pH?

A

-log[H+]

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10
Q

Formula to find out [H+]?

A

10-pH

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11
Q

Relationship between [H+] and [HA] for a STRONG ACID?

A

Due to complete dissociation the [H+] = [HA]

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12
Q

Define a strong acid?

A

Completely dissociates into ions in an aqueous solution

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13
Q

Define a weak acid?

A

Partially dissociates into ions in an aqueous solution

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14
Q

What is the equation for Ka?

A

Ka = [H+] [A-] / [HA]

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15
Q

What does a larger Ka value mean?

A
  • Equilibrium further towards products
  • Greater dissociation
  • Greater acid strength
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16
Q

The stronger the acid the _______ the Ka value and the _______ the pKa

A

Larger
Smaller

17
Q

The weaker the acid the _______ the Ka value and the _______ the pKa

A

Smaller
Larger

18
Q

What do the further dissociations of weak dibasic and tribasic acids result in?

A

Latter dissociations being weak acids and pKa gets larger

19
Q

What are the two assumptions when calculating pH in weak acids?

A

1) [H+]eqm = [A-]eqm (assumes dissociation of water is negligible)
2) [HA]eqm = [HA]start (assumes [HA] is > than [H+]eqm)

20
Q

How can the Ka expression be simplified for WEAK ACIDS?

A

Ka = [H+]2 / [HA]

21
Q

What is the equation, value and units of Kw?

A

Kw = [H+] [OH-] = 1.00 x 10-14 mol2 dm-6