What prediction did Mendeleev make that came true less than 20 years later? A. He predicted the atomic numbers of unknown elements.

B. He said that three new elements would be discovered.

C, He predicted that a total of 112 elements would be discovered.

D. He said that the periodic table would be developed into 18 families.

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final