chloeukc Posted October 30, 2007 Share Posted October 30, 2007 I have this question to do.. and I've been stuck on it for AGES! Please help! Calcium in a sample solution was determined by atomic absorption spectrophotometry. A stock solution of calcium was prepared by dissolving 3.668 g CaCl2.2H2O in water and diluting to 1000 cm3. This was diluted 1:10. Standards were prepared by diluting the second solution, respectively, 1:20, 1:10 and 1:5. The sample solution was diluted 1:25. Strontium chloride was added to all solutions before dilution. Absorbance signals, when the solutions were aspirated into an air-acetylene flame, were as follows: standards, 9.1, 18.6, 37.0; sample 20.9. What was the concentration of calcium in the sample in parts per million? Link to comment Share on other sites More sharing options...
John Cuthber Posted October 31, 2007 Share Posted October 31, 2007 Work out the concentration of calcium in all the standard solutions. Plot a graph of the absorbance vs concentration. Look on the graph to find what concentration corresponds to 20.8 then remember that it had been diluted and calculate the original concentration. Link to comment Share on other sites More sharing options...
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