[ST_08_09]

I know these questions are from the fundamentals of chemistry but I have just started too 

Why are so many exothermic reactions spontaneous ?
how an endothermic reactions can be spontaneous ?

[Ak]

im no expert...but if u want a basic answer to the 1st question...exothermic rxns release energy, meaning tht the products have less energy and are therefore more stable..and things tend to want to be more stable...plus since the reaction is releasing more energy then its absorbing it tends to be favoured...its like going down a hill (exothermic) compared to climbing a hill (endothermic), its easier to go down then up because theres less energy involved

thts just a basic answer im sure one of the pros on this site will give u a better one

[Astrokel]

how an endothermic reactions can be spontaneous ?

Alter the temperature to which you carry out the reaction