Assume that our dye compound, XA, undergoes the following equilibrium in aqueous solution: XA(aq) ⇄ X+(aq) + A−(aq) (Both X+(aq) and A−(aq) are colorless) If a solution initially contains 65.4 μM XA and no X+ or A− prior to equilibrium, what are the concentrations of all three species if the equilibrium mixture gives an absorbance of 0.223 measured at a wavelength of 500.0 nm? Report answer in units of μM. (Hint: ICE and you know some equilibrium information.)

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

Which class of molecules functions as chemical signals? hormones water carbohydrates proteins

Which characteristics can be used to differentiate star systems? check all that apply.