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Measurement of a Half-Life:
A new element has just been “discovered,” and you as a scientist have been assigned to determine if the radioactive element is dangerous to humans or not. Unfortunately, your Geiger counter is in the shop. You decide the best way to determine if the element will kill is to calculate its radioactive half-life. Elements with short half-lives are much more radioactive and dangerous than those with long half-lives.

Earlier observations were made that determined that the element now called “candium” developed a strange “S-shaped” marking upon decay. An element that has decayed has been converted to another element. The production of this new element is indicated in “candium” by the appearance of the “S” on its surface. A half-life is the time it takes half of a sample of an element’s atoms to decay to another element. So if you monitor the rate at which the element “candium” decays you can determine its half-life.

The Purex Process for Recovery of Uranium
           Purex is the short name for the Plutonium/Uranium Extraction Process that is used to recover uranium from nuclear waste so that it can be used again.  This process is what chemists call a solvent extraction.  A solvent extraction takes advantage of a chemical’s desire to be in one solvent rather than another.  Thus by placing the chemical in contact with both solvents in a tube or separatory funnel, the chemical of interest will move into the solvent for which it has the highest affinity.  This can, therefore, be used to separate one chemical from several others as long as their affinities differ from the chemical of interest.  In today’s lab you will be extracting normal uranium from an aqueous phase into an organic phase using the Purex process.