What is the half-life of an isotope if 125 g of a 500 g sample of the isotope remain after 3.0 years

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

Select the correct answer. given: 2libr + ba → babr2 + 2li in this chemical reaction, 325 grams of barium (ba) react completely. how many moles of lithium (li) are produced? a. 1.18 mol b. 2.37 mol c. 4.73 mol d. 16.4 mol e. 32.9 mol

What is the mass of 4 molecules of co2