What is a example of one natural source of radioactivity

Write the overall equation for the reaction for lithium battery

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5

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