X-245 has a half-life, measuring in 8.5 hours. If you have a 2500 gram sample of this substance, how long will it take until you only have 1 gram sample remaining? (answer in hours)

An exothermic reaction is conducted in an insulated calorimeter filled with water. the calorimeter is then sealed so that there is no heat exchanged between the contents of the container and the surrounding air. which of the following statements is true about the reaction?

Structure of the atoms: discovery of the nucleus in 1909i need answering all of these questions

What atom has the largest atomic radius