College of the Canyons

$4.$ A stock solution of $1\mathrm{.}00mM-$carotene was diluted to prepare standard solutions.

a$.$ Calculate the concentration of each dilution. $($Hint: Convert to molarity before you do any dilution calculations

$1.30m,$ Final volume,

Volume of original solution, $mL,mL,$ Final concentration, $M$

$\backslash$table$[[$Dilution A$,5\mathrm{.}00mL$ stock solution $(1\mathrm{.}00mM),50\mathrm{.}00mL,],[$Dilution B$,5\mathrm{.}00mL$ of Dilution A$,25\mathrm{.}00mL,],[$Dilution C$,5\mathrm{.}00mL$ of Dilution B$,25\mathrm{.}00mL,],[$Dilution D$,5\mathrm{.}00$ of Dilution C$,10\mathrm{.}00mL,]]$

$($Show work.$)$

$n=\frac{m}{M}$

$5{10}^{-3},lnM={10}^{-3}M$

$,lnM\frac{{10}^{-3}M}{lnM}=1{10}^{-3}M$

$1\mathrm{.}000\mathrm{.}001=0\mathrm{.}001$mal

b$.$ The molar absorptivity constant for $-$carotene at its analytical wavelength is $139,500M^{-1}c{m}^{-1}.$ Use Beer's Law to predict the absorbance of Dilution D$.$