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Four new elements added to periodic table The new elements – elements 113, 115, 117 and 118 – complete the periodic table’s seventh r...

## Wednesday, 27 July 2016

### Numerical

Guanosine has a maximum absorbance of 275 nm. ${ϵ}_{275}=8400{M}^{-1}c{m}^{-1}$ and the path length is 1 cm. Using a spectrophotometer, you find the that ${A}_{275}=0.70$.  What is the concentration of guanosine?
SOLUTION
To solve this problem, you must use Beer's Law.
$A=ϵlc$
0.70 = (8400 M-1 cm-1)(1 cm)($c$
Next, divide both side by [(8400 M-1 cm-1)(1 cm)]
c$c$ = 8.33x10-5 mol/L