dazed is a stun for 1 turn (until that unit gets its turn again),
weakened is -1 to attack,
you can get -1 to armour,
and a damage effect - not sure how that damage is calculated but i've seen it go between 4 damge to 17 damage.
there is also a slow effect i think.
edit: pandamonium is mass chaos effect, their effects will stack with each other.