March 28, 2024, 02:57:35 PM
Forum Rules: Read This Before Posting


Topic: concentration problem  (Read 1506 times)

0 Members and 1 Guest are viewing this topic.

Offline fatghost13

  • Regular Member
  • ***
  • Posts: 19
  • Mole Snacks: +0/-1
concentration problem
« on: August 08, 2013, 10:52:14 AM »
The amount of chromium in a solution is to be determined by atomic absorption spectroscopy.
It is found that when 10.0 cm^3 of the unknown is diluted to 50.0 cm^3 the absorbance is measured as 0.201. A unknown sample of 10.0 cm3 is then added to 30.0 cm^3 of a solution containing 18.7 mg dm3- of chromium and the mixture diluted to 50.0 cm^3; the absorbance of the second solution is found to be 0.603.
Given that the absorbance of the test solution is directly proportional to the concentration of the analyte, calculate the concentration of the unknown chromium solution.

As  absorbance  proportional to the concentration A1/A2=C1/C2 , A1=0.201 A2=0.603 ,
how can i find C1 and C2 ?
« Last Edit: August 08, 2013, 11:32:18 AM by fatghost13 »

Offline Hunter2

  • Sr. Member
  • *****
  • Posts: 2153
  • Mole Snacks: +162/-47
  • Gender: Male
  • Vena Lausa moris pax drux bis totis
Re: concentration problem
« Reply #1 on: August 09, 2013, 01:10:27 AM »
You will have two equations.  A1 = k*C  and A2 = k*(add+C) Start with this

Sponsored Links