Acids and Bases Flashcards

1
Q

Arrhenius Acid

A

A substance that dissociates in water to produce H⁺ ions

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

Arrhenius base

A

A substance that dissociates in water to produce OH⁻ ions

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

Bronsted Lowry Acid

A

A proton [H⁺] donor

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

Bronsted Lowry Base

A

A proton [H⁺] acceptor

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

Neutralisation

A

The reaction between an acid + a base

forming a salt + water

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

Conjugate Acid

A

formed when a base accepts a proton

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

Conjugate Base

A

formed when an acid donates a proton

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

Conjugate pair

A

an acid + a base that differ by a proton

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

Primary standard

A

Substance of high Mr (Relative Molecular Mass) which can be obtained in a pure stable soluble solid form

  • so it can be weighed out
  • dissolved in water to give a soln of accurately known conc
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Titration

A

laboratory procedure where measured vol of one soln is added to a known vol of another soln until reaction is complete

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

pH formula

A

pH = -log[H⁺]

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

Kw

A

Kw = [H⁺] . [OH⁻]

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

[H⁺]

A

[H⁺] = √Kw

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

Strong acid

A

good proton donor

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

Weak acid

A

weak proton donor

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

Strong base

A

good proton acceptor

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

Weak base

A

poor proton acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

indicator

A

an acid base indicator is a substance that changes colour according to the pH of the soln

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Methyl orange

A

in acid: red
in base: yellow
range: pH 3-5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Phenolphthalein

A

in acid: colourless
in base: pink
range: pH 8-11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Litmus

A

in acid: red
in base: blue
range: pH 5-8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Indicator for: strong acid/base

A

methyl orange
phenolphthalein
litmus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Indicator for: strong acid/weak base

A

methyl orange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Indicator for: weak acid/strong base

A

phenolphthalein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Indicator for: weak acid/weak base

A

none

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Solution

A

a completely perfect mixture of a solute and solvent, where particles of the solute are uniformly distributed throughout the solven

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

concentration

A

amount of solute that is dissolved in a given volume of soln

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

molarity

A

the number of moles of solute per litre of soln

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

No. of moles formula

A

volume x molarity
/
1000

or

mass / Mr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

No of moles in diluted and conc soln

A

[ Vol(dil) x M(dil) ] / 1000 = [ Vol(conc) x M(conc) ] / 1000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

monobasic acids

A

an acid which donates one proton per molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

dibasic acids

A

an acid which donates 2 protons per molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

tribasic acid

A

an acid which donates 3 protons per molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Arrhenius theory of an acid

A

an acid is a substance which dissociates in aqueous soln to form H⁺ ions

HX -> H⁺ + X⁻

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Limitations to the Arrhenius theory (Acid)

A

-limited to reactions taking place in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Arrhenius theory of a base

A

a substance that dissociates in aqueous solution to produce OH⁻ ions

NaOH -> Na⁺ + OH⁻

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Limitations to the Arrhenius theory (Base)

A
  • limited to reactions taking place in water, other solents like methylbenzene or liquid ammonia were exceptions
  • substances such as NH₃ would not be classified as bases (Do not prod. OH⁻ ions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How an acid would react with a base according ot Arrhenius theory

A
  • In soln, acid molecules dissociates + forms H⁺ ions
  • Base molecules dissociates + forms OH⁻ ions
  • H⁺ ions + OH⁻ ions react and form H₂O
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Neutralisation reaction

A

one in which an acid and a base react to form a salt and water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

standard soln

A

soln whose conc is accurately known

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Primary standard criteria

A
  • highly pure state
  • stable in air
  • dissolve easily in water
  • fairly high relative molecular mass
  • should undergo complete + rapid reaction
  • must be anhydrous
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

primary standard eg

A

sodium chloride NaCl

anhydrous sodium carbonte Na₂CO₃

43
Q

equivalence point

A

stage when two solns just react completely with each other

44
Q

end point

A

when the equivalence point is shown by an indicator

45
Q

titration

A

a lab procedure where a measured vol of one soln is added to a known vol of another soln until reaction is complete

46
Q

apparatus used in vol analysis

A
grad cylinder
volumetric flask
pipette
burette
conical flask
47
Q

Bronsted-Lowry theory of an acid + advantage of theory

A
  • an acid is a proton donor (H+) therefore a strong acid is a strong proton donor
  • A base is a proton acceptor

advantage: does not just deal w/ reactions in water

48
Q

conjugate base

A

species formed when an acid has donated a proton

49
Q

strong acid

A
  • an acid which dissociates fully into ions in an aqueous soln
  • every HCl molecule breaks up into ions
50
Q

weak acid

A
  • an acid which only slightly dissociates into ions in an aqueous soln
  • very few of these acid molecules dissociates or beak up into ions
51
Q

why is H2SO4 a strong acid?

A
  • fully dissociates into ions when in an aqueous soln

- has great tendency to break/give protons

52
Q

why strong acids form weak conjugate bases

A

H₂SO₄ -> HSO₄ (strong acid -> weak conj. base)

  • a strong acid such as sulphuric acid readily donates a proton and forms a conj base HSO₄
  • conj base is a weak base as it does not readily accept a proton
53
Q

show that conjugate base H2SO4 can itself act as an acid

A

H₂SO₄ loses a proton + forms the conjugate base HSO₄⁻

54
Q

conjugate base

A

an acid changes into its conjugate base when it donates a proton

55
Q

conjugate acid

A

a base changes into its conjugate acid when it accepts a proton

56
Q

Conjugate acid/bond pair

A

2 substances which differ by an H+ or a proton

57
Q

atmospheric substances

A

a substance which can behave as an acid or base depending on what it reacts with

58
Q

acidity

A

acidity of a soln depends on the conc of H+ ions in the soln

59
Q

Bronsted Lowry’s conjugate pair

A

any pair consisting of an acid and base that differ by H+ or a proton

60
Q

Limitation of the pH scale

A
  • limited to 0-14 range even tho pH values outside range are possible (in theory)
  • does not work w/ very conc solns
  • limited to aqueous solns, chemical reactions can occur in other types of soln
61
Q

self ionisation of water

A

2H₂O ⇌ H₃O⁺ + OH⁻

62
Q

Kc expression

A

[H⁺][OH⁻]/[H₂O]

63
Q

Why is NH₃ considered to be a base according to Bronsted-Lowry theory?

A

NH₃ accepts a proton (H⁺)

64
Q

Ka expression

A

[H⁺][A⁻]/[HA]

65
Q

Kb expression

A

[BH⁺][OH⁻]/[B]

66
Q

Ka

A

Ka = (10⁻ᵖᴴ)²/Mₐ

67
Q

pH using Ka

A

pH = √(Ka)[HA]

=

68
Q

essential property of an indicator used to edetect the end point in a titration between acid and base and their pH curve

A

Changes colour between Phs with straight line in graph

69
Q

define pH

A

pH = -log₁₀[H⁺]

negative log to base ten of hydrogen (hydronium) ion concetration

70
Q

pH curve general shape

A

know general shape

71
Q

explain your selection of indicator for a titration with reference to your pH curve

A

colour change (indicator range) coincides with sharp rise on graph

72
Q

pH using Kb

A

pH = √(Kb)(M)

73
Q

Define Kw (the ionic product of water)

A

Kw = [H⁺][OH⁻]
/ Kw = [H₃O⁺][OH⁻]

Product of molar concentrations of hydrogen (hydronium) ions (H⁺, H₃O⁺) and hydroxide (hydroxyl) ions (OH⁻) in water

74
Q

Vinegar experiment - why was the vinegar diluted?

A
  • Vinegar too concentrated, would require very concentrated (NaOH) solution / very large volume of NaOH needed to get a reasonable titration.
  • Small titration volume lowers accuracy and increases percentage error
75
Q

Describe the correct procedures for measuring exactly an amount of vinegar and diluting it using deionised water

A
  • Rinse pipette with deionised water and then vinegar
  • fill with pipette filler to amount, taking meniscus into account (have bottom of meniscus on mark), read at eye level (Vertically)
  • deliver to volumetric flask
  • add deionised water until level of water near mark
  • add dropwise by dropper and bring bottom of meniscus to mark (at eye level)
  • stopper and invert several times
76
Q

make use of your pH graph to deduce the volume of base required for neutralisation

A

find volume where line is straight

77
Q

Is Chloric(I) acid strong or weak? Give a reason for your answer

A

weak, as low dissociation constant

78
Q

explain how an acid-base indicator, which is itself a weak acid and is represented by HX, functions

A

-the indicator intself dissociates according to the equation HX ⇌ H⁺ + X⁻

  • In base, equilibrium lies on right giving colour of X⁻ ion
  • In acid equilibrium lies on left, giving colour of HX molecule
79
Q

A certain water soluble indicator represented by HIn is a weak acid which dissociates as follows in water:
HIn (green) ⇌ H⁺ + In⁻ (purple)

State and explain the colour observed when a few drops of a solution of the indicator are aded to a 0.5M NaOh solution

A

purple

-hydroxyl ions (OH⁻) remove hydrogen ions (H⁺) causing the reaction to shift to the right

80
Q

explain, by giving a balanced equation for its dissociation in water that the conjugate base of sulfuric acid is itself an acid

A

HSO₄⁻ + H₂O –> SO₄²⁻

+ H₃O⁺

81
Q
  • what compound in white whine is converted to ethanoic acid in vinegar?
  • what type of chemical process converts this to ethanoic acid?
A
  • ethanol

- oxidation

82
Q

conjugate acid of H2O

A

H₃O⁺

hydronium ion

83
Q

in terms of hydrogen ions, account for the difference in pH values between x and y

A

Just use the pH formula, put both of their M into pH formula and label which is which’s pH

eg.
pH HCl = -log(0.10) = 1.00
while pH H2SO4 = -log(0.10) = 0.70

or answer:

  1. 10M HCl produces 0.10M H+ ion (monobasic)
  2. 10M H2SO4 produces 0.20M H+ ion (dibasic)

HCOOH is a weak acid/poor proton donor/weaker than X

84
Q

Methanoic acid formula

A

HCOOH

85
Q

using graph to find volume needed for neutralisation

A

the volume where there is the steepest/straight rise in graph/curve

86
Q

identify two substances acting as base in this equilibrium

A

read question carefully, identify the two bases not the acid and base

87
Q

calculate the conc of H+ ion in nitrous acid and explain how this confirms that it is a weak acid

A

find conc in mol/L, then say

“Ka of nitrous acid is only x” (use it to find Ka)

88
Q

conc of H+ ion in HNO2 (nitrous acid) is 0.01, what conc of nitric acid (HNO3) would have the same H+ ion concentration?

A

Since nitric acid is a strong acid, [HNO3] = [H30+],

so conc = 0.01 mol/L

89
Q

common strong acids and bases

A

learn off some

90
Q

calculate the pH of NH4OH

A

its a base so use pOH to get pH!

91
Q

A certain water soluble acid-base indicator represented by HIn is a waek acid which dissociates as follows in water….
(2012 q10b)
state and explain colour observed when a few drops of a solution of the indicator is added

A

purple

hydroxyl ions/OH- remove hydrogen ions (H+) causing the reaction/equilibrium to shift to the right

92
Q

which of the conjugate bases of these is stronger? Sulfuric acid conj base or the conj base of a weak acid HA? + why

A

A- (the conjugate base of the weak acid)

it is a conjugate base of a weak acid /A- more likely to accept a proton

93
Q

name a suitable indicator for titration between ethanoic acid and NaOH

state colour change

A

phenolphthalein bc its a titration of a weak acid and strong base

colour change: pink to colourless

94
Q

conjugate base of H2O

A

OH- (not HO-)

95
Q

an indicator changes in the pH range 7.6-9.2 for which types of acid-base titrations would it be suitable?

A

strong acid-strong base
and
weak acid-strong base

96
Q

Ka of Chloric(I) acis is 3.7x10^-8 is it a strong acid or weak and why

A

weak as it has low Ka

97
Q

calculate approx percentage dissociation of x

A

Use Ka and equilibrium ICE thing to find conc of [H+]. Then put this value over the molarity (mol/L or mol/dm3) and multiply by 100 to get percentage

OR

-use [H+] = √Ka x Ma , then put [H+] over molarity and multiply by 100 to get percentage

98
Q

pH curve of weak acid and strong base

A
  • steep rise at vol of NaOh that equals vol of acid
  • vertical rise mostly above pH of 7
  • pH starts at original pH of acid
  • label axes, pH axis is 0-14
99
Q

calculate the molarity/concentration of sulfuric acid

A

get the inverse log, then divide the answer by two to get the conc of H+ ions as sulfuric acid (H2SO4) is dibasic and you want the conc of H+ ions

100
Q

with reference to pH graph, why is any indicator suitable for this reaction (strong acid and strong base)

A

most indicators with change around this range

101
Q

calculating water of crystallisation

A
  • Find Mol/L of x, then turn it into mol/vol of original solution first before finding the no. of grams of x.
  • Take away grams of x from grams of crystal to get grams of water
  • find no of moles of x (using Mr of x) and then no of moles of H2O (using Mr of H2O)
  • divide
102
Q

H2F+ + Cl - –> HCl + HF

identify an acid and its conjugate base

A

H2F+ and HF

103
Q

[H+], Ka, and M

A

[H+] = √Ka.M