Someone help with this pls

In 2002, the rare earth elements mine in mountain pass, california was closed because

Adeuteron, 21h, is the nucleus of a hydrogen isotope and consists of one proton and one neutron. the plasma of deuterons in a nuclear fusion reactor must be heated to about 3.02×108 k . what is the rms speed of the deuterons? express your answer using two significant figures.

How do you determine the percent yield of a chemical reaction