i am trying to quit smoking cigarettes and am drinking coffee as an alternative. i've never drank coffee before, when i go into the store i have a choice between "house blend" and decaf. does the house blend already have all the caffiene that i need or do i need to load it up with something? where does the caffeine rush come from? the creamers or the coffee its self?

When 100ml of an aqueous solution containing 1.0g of caffeine is extracted with 10ml of chloroform at room temperature, 0.5 g of caffeine is transferred to the chloroform layer. calculate the distribution coefficient of caffeine between chloroform and water at room temperature.

i have no idea how to do this, because my teacher never really went over it in class, if you could show me how to do this, i'd really appreciate it!
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Caffeine used to never affect me. Now when I drink coffee I feel jittery for a while. Tea and soda doesn't bother me. Could this be related to hypothyroidism?