Wat would happen if both cold air masses had the same temperature

Ok, well assuming they had similar humidities,two similar air masses would just simply mix with no sensible effects caused by the mixing...

If both cold air masses would have the same temperature, they would combine without causing an effect. 

Hope it helped!

It's probably because some types of violets are blue

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen