The half-life of strontium-90 is 28 years. How long will it take a 80-mg sample to decay to a mass of 51.2 mg

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

Schrodinger and heisenberg developed an alternate theory about atomic nature that contradicted some of bohr's model of the atom. how do changes resulting from new technology and evidence affect the reputation of the atomic theory?

What three natural resources are found in the great lakes region