How many grams of potassium are present in 21.6 g of k2cr2o7

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

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

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions