Which sentence is correct? who's going to walk the dog today? whose going to walk the dog today?

The correct answer is the first one, "Who's going to walk the dog today?"

The first one. The word "whose" is possessive, whereas "who's" is a conjunction for "who is." So, the first sentence would be correct if you are trying to ask who is going to walk the dog today. 

Processes above and be sure to mention the movement of electrons and energy as the carbon atom moves from one reaction to another.