Topic 8: Acids and Bases Flashcards

1
Q

What is calcination?

A

A process that refers to the heating of materials to very high temperatures in air in order to bring about their thermal decomposition (in the case of limestone), the removal of water from a hydrated compound (for bauxite), or the removal of a volatile matter from minerals and ores.

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2
Q

Define neutralisation reaction.

A

A combination of an acid and base, ie. reaction involving H^(+) and OH^(-)

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3
Q

Define an acid

A

A proton donor.

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4
Q

Define a base.

A

A proton acceptor.

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5
Q

How is hydronium ion formed?

A

Hydronium ion, H3O^(+) is formed when a water molecule form a coordinate bond with a proton.

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6
Q

What is a conjugate acid-base pair?

A

When a conjugate acid and base differ from one another by a single proton.

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7
Q

What are amphiprotic species?

A

Substances that have the ability to act as either Bronsted-Lowry acid or Bronstead-Lowry base depending on the reaction in which they are taking part.

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8
Q

What colour is litmus for acid?

A

red

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9
Q

What colour is litmus for base?

A

blue

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10
Q

What colour is phenolphthalein for acid?

A

colourless

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11
Q

What colour is phenolphthalein for base?

A

pink

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12
Q

What colour is methyl orange for acid?

A

red

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13
Q

What colour is methyl orange for base?

A

yellow

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14
Q

acid + metal

A

salt + hydrogen

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15
Q

Define salt.

A

Compound composed of an anion and cation

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16
Q

Define standard enthalpy change of neutralisation

A

The energy change associated with the formation of 1 mol of water from the reaction between a strong acid and a strong base under standard conditions.
Has a negative value, because neutralisation is an exothermic process.

17
Q

acid + base

A

salt + water

18
Q

List common bases

A

metal hydroxides
metal oxides
ammonium hydroxide

19
Q

Define an alkali

A

A soluble base.

20
Q

acid + metal carbonate/metal hydrogencarbonate

A

salt + carbon dioxide + water

21
Q

What is titration?

A

A volumetric analysis technique that involves a reaction between a substance of unknown concentration with a standardized solution (the titrant)

22
Q

What is a pH scale?

A

represents the concetration of hydrogen ions, [H^(+)] in a solution.

23
Q

List two expressions that define the pH of a solution.

A

1) pH = -log[H^(+)(aq)]

or

pH = -log[H3O^(+)(aq)]

2) [H^(+)] = 10^(-pH)

24
Q

What is the ion product constant of water, Kw?

A

Kw = [H^(+)][OH^(-)] = 1.0 x 10^(-14) at 298K

25
Q

ionization

A

dissociation

26
Q

List three examples of strong acids

A

HCl

H2SO4, Sulfuric acid

HNO3, nitric acid

27
Q

Define amphoteric

A

species that behaves both as an acid and a base, eg. aluminum hydroxide

28
Q

Describe the enthalpy changes in a neutralisation reaction involving strong acid or base.

A

A strong acid or base completely dissociates in a solution, so the only enthalpy consideration is the exothermic formation of water from hydrogen and hydroxide ions.

29
Q

Describe the enthalpy changes in a neutralisation reaction involving weak acid or base.

A

Weak acid or base is predominantly in their undissociated form in aqueous solution. The ionisation is mildly endothermic. Thus the neutralisation will be less exothermic than for strong acid or base.

30
Q

Define acid deposition

A

Process by which acid-forming pollutants are deposited on the Earth’s surface.
It affects the environment by e.g. deforestation, leaching of minerals from soils leading to elevated acid levels in lakes and rivers, etc

31
Q

What is acid rain?

A

Form of acid deposition caused by increased emissions of nitrogen and sulfur oxides.

the pH of rainwater is 5.6 due to CO2 that forms the weak carbonic acid, however acid rain is <5.6

is the results of the formation of two strong acids: nitric acid (HNO3) and sulfuric acid (H2SO4)