Question

You prepare a standard by weighing 10.751 mg of compound X into a 100 mL volumetric flask and making to volume. You further dilute this solution 5 mL to 25 mL. This standard gives an area of 4,374. Your sample is prepared by adding 5 mL of sample solution into a 50 mL flask and making to volume. This gives an area count of 2,582. Calculate the concentration of compound X in the sample - prior to dilution.

Answer 1

Answer:

0.12693 mg/L

Explanation:

First we calculate the concentration of compound X in the standard prior to dilution:

• 10.751 mg / 100 mL = 0.10751 mg/mL

Then we calculate the concentration of compound X in the standard after dilution:

• 0.10751 mg/mL * 5 mL / 25 mL = 0.021502 mg/L

Now we calculate the concentration of compound X in the sample, using the known concentration of standard and the given areas:

• 2582 * 0.021502 mg/L ÷ 4374 = 0.012693 mg/L

Finally we calculate the concentration of X in the sample prior to dilution:

• 0.012693 mg/L * 50 mL / 5 mL = 0.12693 mg/L