MISSED THIS? Watch KCV The integrated Rale Law, IWE: Determining the Concentration of a Reactant at a Given ;ime Read Section 15.4. You can click on the Review link to access How long will it take for 10% of the U-238 atoms in a sample of U-238 to decay? the section in your eText. Express the number of years to two significant figures. The hall-life for the radioactive decay of U238 is 4.5 billion years and is independent of initial concentration. Part B If a sample of U238 initially contained 1.71018 atoms when the universe was formed 13.8 billion years ago, how many U-238 atoms will it contain today? Express the number of atoms to two significant figures