Brainscape's Knowledge GenomeTM

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


See full index

Chemistry > Acids and Bases > Flashcards

Acids and Bases Flashcards

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

Define a Bronsted-Lowry acid?

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

Define a Bronsted-Lowry base?

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

What ion causes a solution to be acid?

A
  • H⁺ ion
  • more accurately H₃O⁺ (oxonium ion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What causes a solution to be alkaline?

A
  • OH‾ (hydroxide ion)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Write an equation for the ionisation of water (2).

A
  • 2H₂O (l) ⇄ H₃O⁺ (aq) + ‾OH (aq)
  • H₂O (l) ⇄ H⁺(aq) + ‾OH (aq)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Derive Kw using the equation for ionisation of water.

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

What is the value of Kw at 298K?

A
  • 1x10‾¹⁴
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What physical factors affect the value of Kw? How do they affect it?

A
  • Temperature only
  • if temperature is increases the equilibrium moves to the right so Kw increases
  • therefore the pH of pure water decreases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is pure water still neutral, even if pH does not equal 7?

A

[H⁺] = [‾OH]

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

Give an expression for pH in terms of H⁺.

A

pH = -log₁₀[H⁺]

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

What is the relationship between pH and concentration of H⁺?

A
  • lower pH = higher concentration of H⁺
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

If two solutions have a pH difference of 1, what is the difference in [H⁺]?

A
  • a factor of 10
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do you find [H⁺] from pH?

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

How do you find [OH‾] from pH? (at 298K)

A
  • Find [H⁺], use Kw (equal to 1x10‾¹⁴ at 298K) to calculate [‾OH]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is different when finding [H⁺] from the concentration of diprotic acid and triprotic acids?

A
  • need to multiply the concentration of the acid by the number of protons to find [H⁺]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do you calculate the pH of a strong alkaline solution?

A
  • Use Kw to calculate [H⁺] from [OH‾]
  • Use pH = -log₁₀[H⁺]
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define the term strong acid.

A
  • one which fully dissociates in water (HX → H⁺ + X‾)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define the term strong base.

A
  • one which fully dissociates in water (XOH → X⁺ + OH‾)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the difference between concentrated and strong?

A
  • concentrated means many mol dm‾³
  • strong refers to the amount of dissociation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a weak acid and a weak base?

A
  • weak acids and bases do not fully dissociate in water. They only partially dissociate into their ions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give some example of strong acids?

A
  • HCl
  • H₂SO₄
  • H₃PO₄
20
Q

Give some examples of strong bases.

A
  • NaOH
  • CaCO₃
  • Na₂CO₃
21
Q

Give some example of weak acids.

A
  • CH₃COOH (ethanoic), any organic acid
22
Q

Give some example of weak bases.

A
  • NH₃
23
Q

What is Ka? (expression)

A
  • For acid HA:
    HA ⇄ H⁺ + A‾
24
Q

How would you work out the pH of a weak acid?

A
  • Use the equation for Ka, subbing in values for [A‾] and [HA]
  • Use pH = -log₁₀[H⁺] to find pH
25
Q

What is a titration?

A
  • the addition of an acid/base of know concentration to a base/acid of unknown concentration to determine its concentration
  • an indicator is used to show that neutralization has occurred
26
Q

Draw a diagram of the equipment that could be used for a titration.

A
26
Q

Draw the titration curve for a strong acid with a strong base added.

A
27
Q

Draw the titration curve for a strong acid with a weak base added.

A
28
Q

Draw the titration curve for a weak acid with a weak base added.

A
29
Q

Draw the titration curve for a weak acid with a strong base added.

A
30
Q

Define the term equivalence point.

A
  • the point at which the exact volume of base has been added to just neutralise the acid, or vice-versa
31
Q

What generally happens to the pH of the solution around the equivalence point?

A
  • there is a large and rapid change in pH
  • except in the weak-weak titration
32
Q

How would you calculate the concentration of a reactant if you know the volume and conc of the other reactant and the volume of that reactant.

A
  • calculate moles of one reactant
  • use balanced equation to work out moles of the other
  • use conc = mol/volume to calculate concentration
33
Q

What is the end point?

A
  • the volume of acid or alkali added when the indicator just changes colour.
  • if the right indicator is chosen: equivalence = end point
34
Q

What are the properties of a good indicator for a reaction? (3)

A
  • sharp colour change (not gradual)
  • end point must be the same as the equivalence point, or titration gives wrong answer
  • distinct colour change so it is obvious when the end point has been reached
35
Q

What indicator would you use for a strong acid - strong base titration?

A
  • phenolphthalein or methyl orange
36
Q

What indicator would you use for a strong acid - weak base titration?

A
  • Methyl orange
37
Q

What indicator would you use for a strong base - weak acid titration?

A
  • Phenylphthalein
38
Q

What indicator would you use from a weak acid - weak base titration?

A
  • neither methyl orange or phenolphthalein is suitable
39
Q

What colour is methyl orange in acid? In alkali? At what pH does it change?

A
  • Red in acid, yellow in alkali
  • pH = 3-5
40
Q

What colour is phenolphthalein in acid? In alkali? At what pH does it change?

A
  • colourless in acid, pink in alkali
  • changes at about pH = 8-10
41
Q

Define a buffer solution.

A
  • a solution that resists changes in pH when small amount of acid/alkali are added
42
Q

What do acidic buffer solution contain in general terms?

A
  • A weak acid and a soluble salt of that acid that fully dissociates
43
Q

Write a reaction for an acidic buffer with added acid.

A
  • A‾ + H⁺ → HA
  • opposes addition of H⁺
44
Q

Write a reaction for an acidic buffer with added alkali.

A
  • HA + OH‾ → H₂O + A‾
45
Q

What do basic buffer solutions contain in general terms?

A
  • weak base and soluble salt of that weak base
46
Q

How can you calculate the pH of buffer solutions?

A
  • Use the Ka of the weak acid, sub in [A‾] and [HA] calculate [H⁺] → pH
47
Q

How can you calculate the new pH of a buffer solution when acid or base is added?

A
  • calculate the number of moles of H⁺ and A‾ and HA before acid or base is added
  • Use equations to work new moles of A‾ and HA → find [H⁺] → pH
48
Q

What products are buffers found in?

A
  • shampoos, detergents → important to keep pH right to avoid damage to skin, hair, fabrics
49
Q
A

Chemistry (24 decks)

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