Question

concentration of an organic compound consists of azo linkage (-N-N-), benzene and naphthalene ring is to be determined by UV-visible spectrophotometry. In a typical analysis, a set of standard solutions molarity are prepared before determine the absorbance of the solution. The absorbance measured are then summarised in the following Table 2. Concentration (ppm) 0.5 1.0 Absorbance 0.24 0.30 0.36 0.39 0.44 0.50 Table 2: The absorbance and concentration of an organic compound. i) Determine the slope and intercept of the measured data using the linear least squares method. (6 Marks) From the calculated data in part d (1), determine the concentration of the solution of an organic compound with a known absorbance of 0.375. (2 Marks) ii)

Answer 1

Soleution () 0.5 024 0-12 0.25 0.30 0.1 1.5 2.25 2 0 0.37 0.71 2.5 0.44 6.25 3.0 0.50 1-5 Sx: t0.5 :2-23 =D439 Let E2y = a Ext bex 2.23= (1o-5+ 66 4.34 =al22.49-+ b(las) Sare =t0.09 Jnterapt S1967 (1) 0.395 o.1767 cmC= 1801 FAm