If you start with 20 kg of a radioactive isotope, calculate how much of the original isotope is left after one half-life has elapsed? Write your answer in decimal kg, and as a fraction of the original.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

so she was walking and she stepped on warm jeffy , uh uh uhh dadye i just pooped my pants