What is a limited resource in the use of nuclear fission for energy?

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

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and explain your predictions. how does temperature affect the spontaneity of this process?