An original sample of k-40 has a mass of 25.00 grams. after 3.9 m 109 years, 3.125 grams of the original sample remains unchanged. what is the half-life of k-40?

Which formula can be used to calculate the molar mass of ammonia (nh3)? molar mass of n + molar mass of h 3 × molar mass of n + molar mass of h molar mass of n + 3 × molar mass of h 3 × molar mass of n + 3 × molar mass of h

Which two scientific disciplines are bridged by pharmaceutical drugs? chemistry and forensics chemistry and medicine biology and forensics biology and criminology

The picture represents the process that produces most of the energy used by living organisms on earth. which process is represented in the picture? a) the magnetic attraction between two hydrogen nuclei. b) the fusion of hydrogen nuclei to produce a helium nucleus in the core of the sun. c) the fission of hydrogen nuclei to produce a helium nucleus in the core of the sun. d) the chemical reaction between hydrogen nuclei to produce a helium nucleus in earth's atmosphere.