If the molar mass of a substance is found to be 638 grams/mole, what is the molecular formula?

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

Match each statement with the state of matter it describes

Wind and moving water provide energy. chemical mechanical thermal none of the above