Acids and Bases Flashcards
Arrhenius Acid
A substance that dissociates in water to produce H⁺ ions
Arrhenius base
A substance that dissociates in water to produce OH⁻ ions
Bronsted Lowry Acid
A proton [H⁺] donor
Bronsted Lowry Base
A proton [H⁺] acceptor
Neutralisation
The reaction between an acid + a base
forming a salt + water
Conjugate Acid
formed when a base accepts a proton
Conjugate Base
formed when an acid donates a proton
Conjugate pair
an acid + a base that differ by a proton
Primary standard
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
Titration
laboratory procedure where measured vol of one soln is added to a known vol of another soln until reaction is complete
pH formula
pH = -log[H⁺]
Kw
Kw = [H⁺] . [OH⁻]
[H⁺]
[H⁺] = √Kw
Strong acid
good proton donor
Weak acid
weak proton donor
Strong base
good proton acceptor
Weak base
poor proton acceptor
indicator
an acid base indicator is a substance that changes colour according to the pH of the soln
Methyl orange
in acid: red
in base: yellow
range: pH 3-5
Phenolphthalein
in acid: colourless
in base: pink
range: pH 8-11
Litmus
in acid: red
in base: blue
range: pH 5-8
Indicator for: strong acid/base
methyl orange
phenolphthalein
litmus
Indicator for: strong acid/weak base
methyl orange
Indicator for: weak acid/strong base
phenolphthalein
Indicator for: weak acid/weak base
none
Solution
a completely perfect mixture of a solute and solvent, where particles of the solute are uniformly distributed throughout the solven
concentration
amount of solute that is dissolved in a given volume of soln
molarity
the number of moles of solute per litre of soln
No. of moles formula
volume x molarity
/
1000
or
mass / Mr
No of moles in diluted and conc soln
[ Vol(dil) x M(dil) ] / 1000 = [ Vol(conc) x M(conc) ] / 1000
monobasic acids
an acid which donates one proton per molecule
dibasic acids
an acid which donates 2 protons per molecule
tribasic acid
an acid which donates 3 protons per molecule
Arrhenius theory of an acid
an acid is a substance which dissociates in aqueous soln to form H⁺ ions
HX -> H⁺ + X⁻
Limitations to the Arrhenius theory (Acid)
-limited to reactions taking place in water
Arrhenius theory of a base
a substance that dissociates in aqueous solution to produce OH⁻ ions
NaOH -> Na⁺ + OH⁻
Limitations to the Arrhenius theory (Base)
- 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 an acid would react with a base according ot Arrhenius theory
- In soln, acid molecules dissociates + forms H⁺ ions
- Base molecules dissociates + forms OH⁻ ions
- H⁺ ions + OH⁻ ions react and form H₂O
Neutralisation reaction
one in which an acid and a base react to form a salt and water
standard soln
soln whose conc is accurately known
Primary standard criteria
- highly pure state
- stable in air
- dissolve easily in water
- fairly high relative molecular mass
- should undergo complete + rapid reaction
- must be anhydrous