Reactions cannot occur without a certain minimum amount of energy. what is this minimum amount of energy called?

In a heat engine of 1000 j of heat enters the system and the piston does 500 j of work what is the final internal energy of the system if the inital energy was 2000 j we have to do all of these down here 1)write the equation 2)list out your know variables 3)plug the numbers into the equations 4)solve 5)write your solution statemtn that includes inital energuy and final energuy added

How does the atmosphere to make earth livable? check all that apply. causes the seasons contains oxygen provides warmth creates important nutrients blocks harmful energy from the sun plz like !

In which region is the substance in both the solid phase and the liquid phase? 1 2. 3 4 mark this and return save and exit next