Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

HL Chemistry > Topic 8: Acids and Bases > Flashcards

Topic 8: Acids and Bases Flashcards

You may prefer our related Brainscape-certified flashcards:
Periodic Table flashcards Chemistry 101 flashcards AP® Chemistry flashcards Organic Chemistry 101 flashcards
1
Q

What is the Bronsted-Lowry theory of Acids and Bases?

A

Acids are proton/H+ donors. Bases are proton/H+ acceptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What charges do the conjugate pairs gain?

A

The conjugate acid gains a positive charge.
The conjugate base gains a negative charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What colour is Litmus in acids and bases?

A

Red in acids.
Blue in bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What colour is Methyl orange in acids and bases?

A

Red in acids.
Yellow in bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What colour is phenolphthalein in acids and bases?

A

Colourless in acids.
Pink in bases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Give the formula for an acid reacting with a base

A

Acid + base —> Salt + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give the formula for an acid reacting with a metal oxide

A

Acid + metal oxide —> Salt + water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give the formula for an acid reacting with a metal

A

Acid + metal —> Salt + hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give the formula for an acid reacting with a carbonate

A

Acid + carbonate —> Salt + water + carbon dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does a change of one pH unit represent?
And if the pH increases how does this affect [H+]?

A

A ten-fold change in [H+].
Increase in pH = decrease in [H+]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Dilute acids vs concentrated acids (+ what ion does so)

A

Dilute acids demonstrate the typical properties of acids.
i.e. they turn litmus red

Concentrated acids do not demonstrate the typical properties of acids.

*IT IS THE HYDRONIUM ION THAT GIVES ACIDS THEIR ACID PROPERTIES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define strong acids

A

Strong acids ionize/dissociate almost completely in water. “—>”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define weak acids

A

Weak acids will transfer a few protons to water. They mostly remain as molecules. “⇌”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give three examples of strong acids and three examples of weak acids

A

Hydrochloric acid (HCl)
Nitric acid (HNO₃)
Sulfuric acid (H₂SO₄)
——
Phosphoric acid (H₃PO₄)
Ethanoic acid (CH₃COOH)
Carbonic acid (H₂CO₃)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give four examples of strong bases and two examples of weak bases

A

Lithium hydroxide LiOH
Sodium hydroxide NaOH
Potassium hydroxide KOH
Barium hydroxide Ba(OH)₂
——
Ammonia NH₃
Ethylamine CH₃CH₂NH₂

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Electrical conductivity, rate of reaction and pH for strong and weak acids / bases

A

Strong acids and bases
- Good electrical conductors as lots of ions (charged particles)
- Fast rate of reaction
- pH
Acids: Low as many H+ ions
Bases: High as many OH- ions

Weak acids and bases
- Poor electrical conductors as few ions
- Slow rate of reaction
- pH
Acids: Weakly acidic as less H+ ions
Bases: Weakly basic as less OH- ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

A weak acid has a …
A strong acid has a …

A

strong conjugate base.
weak conjugate base (and vice versa)

18
Q

Normal rainwater vs acid rain

A

Normal rainwater is naturally acidic due to the presence of dissolved carbon dioxide which forms weak carbonic acid. Normal rain has a pH above 5.6.

Acidic rain is caused by sulfur and nitrogen oxides and has a pH below 5.6.

19
Q

Describe how sulfur oxides contribute to acid rain

A

Sulfur dioxide is produced by the burning of fossil fuels.
It can then produce sulfurous acid (H₂SO₃), sulfur trioxide (SO₃) or sulfuric acid (H₂SO₄).

20
Q

Describe how nitrogen oxides contribute to acid rain

A

Nitrogen monoxide is produced by internal combustion engines in vehicles.
It can produce nitrogen dioxide (NO₂), nitrous acid (HNO₂) and nitric acid (HNO₃).

21
Q

What are the effects of acid deposition?

A
  • Impact on materials. Corrodes metals and erodes structures. (Nitrous acid and sulfurous acid)
  • Is toxic to plant life as it stops plants’ ability to undergo photosynthesis and damages the roots.
  • Is toxic to marine life/affects marine ecosystems. Contributes to eutrophication (algae growth) and lake acidification. (Carbonic acid)
  • Can cause respiratory issues in humans.
22
Q

How can SO₂ emissions be reduced?

A

Pre-combustion methods
- Crushing coal and washing with water
- Hydrodesulfurization (reacts sulfur with hydrogen to form hydrogen sulfide)

Post-combustion methods
- Flue gas desulfurization

23
Q

How can NO₂ emissions be reduced?

A

Pre-combustion methods
- Catalytic converters in vehicles
- Lower temperature of combustion (this reduces the amount of nitrogen monoxide produced)

24
Q

What is the Lewis theory of Acids and Bases?

A

A Lewis acid is an electron acceptor (it is electron deficient) i.e. an electrophile

A Lewis base is an electron donor (it is electron-rich) i.e. a nucleophile.
(REMEMBER BASE MAKES BANK BC THEY’RE RICH)

25
Q

What is the value of pKw?

A

14

26
Q

What is the value of Kw?

A

10^-14

27
Q

What type of relationship does K of acids or bases have with pK of acids or bases? Demonstrate with strong acids.

A

Inverse relationship. i.e. in strong acids Ka is high (bc lots of products are formed) and the pKa is low.

28
Q

What are the assumptions we make when calculating the pH of weak acids or bases?

A

The concentration of the products are equal.
The concentration of the reactant stays the same because so little has broken down.

29
Q

Define amphiprotic

A

Able to both donate or accept a proton (act as a Bronsted-Lowry acid or base).

Remember ‘h’ in amphiprotic as H+ is the basis of the Bronsted-Lowry definition.

30
Q

Define amphoteric

A

Able to act as an acid or a base/display acidic or basic properties.

31
Q

Define a buffer solution

A

An aqueous solution consisting of a weak acid/base and its conjugate pair that resists changes to pH when small amounts of acid or base are added. This is because the solution is in equilibrium (Le Chatelier’s principle - the system will act to minimise the effect of the change).

32
Q

Preparations of a buffer solution

A

1) Mixing roughly equal proportions of a weak acid/base and its conjugate pair
2) Partially neutralising a weak acid with a strong base

33
Q

At the equivalence point, a strong acid and a strong base give what pH? (pH curves)

A

pH of 7

34
Q

At the equivalence point, a strong acid and a weak base give what pH? (pH curves)

A

pH<7 (Buffer region is present. This is where the pH is hardly changing.)

35
Q

At the equivalence point, a weak acid and a strong base give what pH? (pH curves)

A

pH>7 (Buffer region is present. This is where the pH is hardly changing.)

36
Q

At the equivalence point, a weak acid and a weak base give what pH? (pH curves)

A

pH of 7

37
Q

Where is the equivalence point on a pH curve?

A

Halfway up the point of inflexion (the steep line).

38
Q

On a pH curve where is the pKa found?

A

Half of the equivalence point.

39
Q

Why with a weak acid and strong base or strong acid and weak base is the pH NOT 7?

A

Because one of the products of the neutralisation reaction will react further in hydrolysis (proton transfer).

40
Q

How do we select an indicator for titrations?

A

If the pKa is + or - 1 of the equivalence point.
i.e. it changes colour at pH values close to the equivalence point and does not interfere with the reaction.

41
Q

What are acid-base indicators?

A

Acid-base indicators are weak acids or weak bases. The species differs in colour from its conjugates.

Hln ⇌ H⁺ + ln⁻
Where Hln is colour 1, ln⁻ is colour 2.

HL Chemistry (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions