Question

Please help! A small amount of caffeine (194.19 g/mol) was dissolved in enough water to make 500 ml of solution. A 2.00 ml aliquot of this solution was then diluted to 100.0 ml. the absorbance of the second solution at 273 nm was 0.463 using a 1.00 cm cuvette. If the molar absorptivity of caffeine at 273 nm is 9 841 M-1 cm-1, how many milligrams of caffeine were used to make the original solution?

Name: please help a small amount of caffeine 19419 gmol was dissolved in enough water to make 500 ml of solution a 200 ml aliquot of this solution was then diluted to 1000 ml the absorbance of the 04194
Uploaded: 2023-03-19T21:59:41-08:00
Duration: 2 min 9 s
Channel: David Collins
Description: please help a small amount of caffeine 19419 gmol was dissolved in enough water to make 500 ml of solution a 200 ml aliquot of this solution was then diluted to 1000 ml the absorbance of the 04194

          Please help! 
A small amount of caffeine (194.19 g/mol) was dissolved in
enough water to make 500 ml of solution. A 2.00 ml aliquot of this
solution was then diluted to 100.0 ml. the absorbance of the second
solution at 273 nm was 0.463 using a 1.00 cm cuvette. If the molar
absorptivity of caffeine at 273 nm is 9 841 M-1 cm-1, how many
milligrams of caffeine were used to make the original solution?

Added by Bruce L.

Chemistry: Structure and Properties

Nivaldo Tro 2nd Edition

Instant Answer

Solved by Expert David Collins

03/19/2023

Step 1

First, we need to find the concentration of caffeine in the second solution using the absorbance value and the molar absorptivity. A = ε * c * l where A is the absorbance, ε is the molar absorptivity, c is the concentration, and l is the path length of the Show more…

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Please help! A small amount of caffeine (194.19 g/mol) was dissolved in enough water to make 500 ml of solution. A 2.00 ml aliquot of this solution was then diluted to 100.0 ml. the absorbance of the second solution at 273 nm was 0.463 using a 1.00 cm cuvette. If the molar absorptivity of caffeine at 273 nm is 9 841 M-1 cm-1, how many milligrams of caffeine were used to make the original solution?