Caffeine, C 8 H 10 N 4 O 2 , is a stimulant found in tea and coffee. A sample of
ID: 963385 • Letter: C
Question
Caffeine, C8H10N4O2, is a stimulant found in tea and coffee. A sample of the substance is dissolved in 45.0 g of chloroform, CHCl3, to give 0.0946 m solution. How many grams of caffeine were in the sample? Caffeine, C8H10N4O2, is a stimulant found in tea and coffee. A sample of the substance is dissolved in 45.0 g of chloroform, CHCl3, to give 0.0946 m solution. How many grams of caffeine were in the sample? Caffeine, C8H10N4O2, is a stimulant found in tea and coffee. A sample of the substance is dissolved in 45.0 g of chloroform, CHCl3, to give 0.0946 m solution. How many grams of caffeine were in the sample?Explanation / Answer
m solvnet = 45 g
molality = mol S / kg solvent = 0.0946
mol S = ?
kg solvnet = 44/1000 = 0.045
mol S = 0.0946*0.045 = 0.004257 mol of S
MW of S = 194.19
mass = mol*MW = 194.19 *0.004257 = 0.82666683 g of Caffeine