Acrostic poem of proclamation

What is the percentage composition of carbon in the compound ch4

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

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