What is the difference between pioneer species and climax communities

Iwould appreciate if someone could me.

How many liters of ethylene glycol antifreeze (c2h6o2), with a density of 1.100 g/l, would you add to your car radiator containing 15.0 kg of water if you needed to protect your engine to - 21.5°c? for water, kf = 1.86°c m -1.

What information does a complete ionic equation give that the balanced equation doesn’t show?