An element "E" is present as 10E with a mass value of 10.01 amu, and as 11E with a value of 11E amu. The natural abundances of 10E and 11E are 19.78% and 80.22% respectively. What is the average atomic mass of the element? What is the element?

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.