Acids and Bases Flashcards
Arrhenius definition of an acid
An acid is a substance that dissociates in water to produce H+ ions
Arrhenius definition of A base
Is a substance that dissociates in water to form OH- ions
Arrhenius definition of A strong acid
A substance that almost completely dissociates in water to give H ions
Arrhenius definition of A weak acid
A substance that only slightly dissociates in water to give H ions
Arrhenius definition of a strong base
A substance that almost completely dissociates in water to form OH ions
Arrhenius definition of A weak base
Substance that only slightly dissociates in water to give hydroxide ions
Brønsted-Lowry definition of an acid
An acid is a proton donor
Brønsted-Lowry definition of A base
A proton acceptor
Brønsted-Lowry definition of Strong acid
A good proton donor
Brønsted-Lowry definition of A weak acid
Poor proton donor
Brønsted-Lowry definition of A strong base
Good proton acceptor
Brønsted-Lowry definition of A weak base
Poor proton acceptor
What is an alkali
A base that is solvable in water
What is a proton otherwise known as
A H+ ion
What does the Equilibrium symbol mean?
Reaction is going in both directions Ie you cannot know moles from the balanced equation
What is a monoprotic/basic acid
An acid that dissociates to give one proton
What is a diprotic/basic acids
An acid that dissociates to give 2 protons
Give an example of a monoprotic balanced equation
HCl=H+ + Cl-
Give an example of a diprotic balanced equation
H2SO4 + H2O = H3O+ + HSO4-
What are the limitations to Arrhenius’ theory of acids and bases
H+ ions do not exist on their own in solution. They form the H3O+ ion
Arrhenius’ definitions are restricted to aqueous solutions. Water is not the only solvent
NH3 cannot be considered a base
Compare Arrhenius and Brønsted-Lowry
Arrhenius:
-Theory is restricted to only aqueous solutions
-bases produce OH- ions in water
- does not take hydronium ion formation into account
Brønsted-Lowry:
-can involve reactions that occur in the gaseous state
- not all bases produces OH- ions for example NH3
- takes hydronium ion formation into account
What does amphoteric mean
Behave as either an acid or a base
Under what circumstances do acids become conjugate bases?
When it donates a proton
Under what circumstances does a base become a conjugate acid
Accepts a proton
What is a conjugate base pair
Any pair consisting of an acid and a base that differ by a proton
How to find the conjugate base
Decrees no of H by 1
Decrease charge by 1
How to find conjugate acid
Increase no of H by 1
Increase charge by 1
What does a strong acid have
Weak conjugate base
What does a weak acid have
A strong conjugate base
Why do strong acids have weak conjugate bases
Strong acids fully disassociate In water and it is unlikely for a reaction to go in the reverse direction thus it is a weak base
Write a balanced equation to show how acid dissociates in water
Acid + water = weak base + acid
Neutralisation
A reaction between an acid and a base, forming a salt and a water
Eg of a neutralisation balanced equation
NaOH+HCl ->NaCl + H2O
What is a salt
A substances formed when the H+ ion from an acid is replaced by a metal or ammonium ion
Give an example of a balanced equation of a salt
NaOH + HCl -> NaCl + H2O
Give 2 examples of a neutralisation reaction
Agriculture- if soil is too acidic lime is spread on soil to increase pH. Some crops do not grow well in acidic soil
CaO + H2O -> Ca(OH)2
Environmental- In areas where acid rain is a problem limestone is added to lakes to increase pH
H2SO4 + CaCO3 -> CaSO4 + H2O + CO2
