In a sample of 400 lithium atoms, it is found that 30 atoms are lithium-6 (6.015 amu) and 370 atoms are lithium-7 (7.016 amu). What is the average atomic mass?

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

Nonpoint source pollution is difficult to control because it

Consider the story you just read. all but one of the choices below indicate that something is living.