acids and bases Flashcards
what are conjugated bonds
alternating single and double bonds
what does conjugation change
enhances stability, changes structure, different reactivity, changes spectroscopic behaviour (can absorb uv maybe)
relationship between conjugation and wavelength
more conjugation=longer wavelength of light absorbed
why do some polyenes appear coloured
they have many conjugated double bonds so they can absorb light in the visible region of spectrum so they appear coloured
what colour will substances appear if they absorb visible light
the colour will appear as the complementary colour to the one absorbed (colour opposite on colour wheel)
describe the structure of benzene
aromatic and a conjugated molecule, all bonds are same length and are partial double bonds, delocalised pi electrons around/above/below plane
how to tell if a molecule is aromatic
Huckels rule, 4n+1=number of pi electrons, if n is whole number then it is aromatic
what is a arrhenius acid
a substance that increases concentratino of H+ when dissolved in water
what is an arrhenius base
a substance that increases the concentration of OH_ when dissolved in water
what is a arrhenius acid base reaction
an acid reacts with a base to create water and a salt, often called neutralisation
what is a bronsted lowry acid
H+ donor, substance that can donate a hydrogen ion
what is a bronsted lowry base
H+ acceptor, substance that can accept a hydrogen ion
what is a bronsted lowry acid base reaction
transfer of a hydrogen ion
why are arrhenius definitions limited
requires water as a solvent, liquid phase, only depends on two ions (restricted by solvent and phase)
why is the bronsted lowry definitions a broader definition than arrhenius
not solvent restricted, not phase restricted but still restricted by hydrogen ion
