8.1 Flashcards
early theories 1
French chemist Lavoiser
1777
Oxygen = acid former
acid = oxygen + non-metal
had to be dismissed when the acid HCl was proven to not contain oxygen
early theories 2
Swedish chemist - Arrhenius
1887
Acid + H2O = anion + H+
Base + H2O = cation + OH-
his focus was only on aqueous systems
What is dissociation?
Dissolves and formes an anion
who invented Bronsted - Lowry theory and when?
Martin Lowry and Johannes Bronsted in 1923
What does Bronsted - Lowry theory state?
A Brosted - Lowry acid is a proton donor and a base is a proton acceptor
What is H+ equivalent to?
a proton
what is a conjugate acid-base pair?
The acid and base in a conjugate acid base pair differ by just one proton.
A general example of a conjugate acid base pair
HA + B = A- + BH+
HA - generic acid B - base
(HA and A) and (B and BH+) are conjugate acid pairs since they differ by only 1 proton (H+)
Sometimes there is only 1 conjugate acid base pair e.g.
H2O + H+ = H3O+
H2O and H3O is the acid base pair
Which one has more number of protons?
acid
What does an acid need to be a bronsted- lowry acid?
- have hydrogen
- be able to lose a proton (dissociate and release H+ )
What does a base need to be a bronsted- lowry base?
be able to accept a proton ( must have a lone pair)
What is an Amphiprotic substance
An Amphiprotic substance is one which can act as both a proton donor and proton acceptor.
An example of an amphiprotic subtance
H2O
CH3COOH + H2O = CH3COO- + H3O + ( here H2O is a base)
NH3 + H2O = NH4+ OH-
( Here H2O is an acid )
is H3O+ amphiprotic?
H3O+ can theoretically be amphiprotic but in practice it is not because oxygen isn’t strong enough to hold 4 hydrogens.
