How many mole are in 2.84*10^22 molecules of h2

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

What does the process of natural selection involve

The diagram below shows a cell placed in a solution. a cell is shown placed inside a beaker. it is labeled cell. the solution inside the beaker is labeled 40% salt solution and the solution inside the cell is labeled 20% salt solution. only water is allowed to move in and out of the cell. what will most likely happen to the cell? it will expand as water moves out of it. it will shrink as water moves out of it. it will expand as water moves into it. it will shrink as water moves into it.