Question

1. The height of three peaks; A, B, and C obtained in a gas chromatogram are 27.7 mm, 19.2 mm and 41.0 mm. The width of the peaks, at half height, are 4.9 mm, 4.7 mm and 4.6 mm, respectively. Calculate the percentage composition of C in the sample. Answer in : %

2. A gas chromatograph can be used to (more than one answer may be correct)

-determine the mass of a compound.

-determine the percentage composition of a mixture.

-purify large quantities of compounds.

-separate vaporizable compounds.

-separate nonvolatile compounds

Answer 1

This is representative GC chomatogram 1. h-41.0 mm TASTA h-27.7 mm Wi46 mm h-19.2 mm Wi 49 mm 2 4.7 mm C В The peak in chromatogram conside ed to be triangle, Hence area of peak can be calculated by following fomula Area of Peak A= height (h) * width of half height = 27.7 mm " 4.9 mm =135.73 mm2 Total area of pe aks A,B & C Area of Peak B = height (h)* width of half height (mm2 4,7 mm = 19.2 mm = 135.73 90.24 188.60 =90.24 mm =414.57 mm2 Area of Peak C height (h)* width of half height = 41.0 mm * 4.6 mm = 188.60 mm2 % Aea under pe ak cab calculated by following la, Area of peak A Total aea Area of peak B Total area х 100 % Агеа оf peak В %- X 100 135.73 mm 414.57 mm 90.24mm X 100 414.57 mmX 100 32.73 21.77 % Area of peak C Total area X 100 % Area of peakC 188.60 mm2 X 100 414.57 mm 45.50 compos ition of C= 45.50% Hence 2. A gas chomatograph can be used to- 1. Detemine the mass of a compound 2. Detemine the percentage composition of a mixture 3. Separate vaporizable compounds

This is representative GC chomatogram 1. h-41.0 mm TASTA h-27.7 mm Wi46 mm h-19.2 mm Wi 49 mm 2 4.7 mm C В The peak in chromatogram conside ed to be triangle, Hence area of peak can be calculated by following fomula Area of Peak A= height (h) * width of half height = 27.7 mm " 4.9 mm =135.73 mm2 Total area of pe aks A,B & C Area of Peak B = height (h)* width of half height (mm2 4,7 mm = 19.2 mm = 135.73 90.24 188.60 =90.24 mm =414.57 mm2 Area of Peak C height (h)* width of half height = 41.0 mm * 4.6 mm = 188.60 mm2 % Aea under pe ak cab calculated by following la, Area of peak A Total aea Area of peak B Total area х 100 % Агеа оf peak В %- X 100 135.73 mm 414.57 mm 90.24mm X 100 414.57 mmX 100 32.73 21.77 % Area of peak C Total area X 100 % Area of peakC 188.60 mm2 X 100 414.57 mm 45.50 compos ition of C= 45.50% Hence 2. A gas chomatograph can be used to- 1. Detemine the mass of a compound 2. Detemine the percentage composition of a mixture 3. Separate vaporizable compounds