#4 . Thallium-201 has a half life of 73 hours. If 4.0 mg of thallium-201 disintegrates over a period of 6 days and 2 hours how many mg of thallium will remain

Identify the electromagnets with poles that are reversed from the electromagnet shown above

How could a student test the effect of removing heat from a gas that is stored in a sealed container? what must occur in order for matter to change states?

Butane gas reacts with oxygen gas to give carbon dioxide gas and water vapor (gas). if you mix butane and oxygen in the correct stoichiometric ratio, and if the total pressure of the mixture is 390 mmhg, what is the pressure (in mmhg) of water vapor after the reaction is completed (temperature and volume do not change).