help on the following questions pls.
You determine lead in an unknown sediment sample using an analytical instrument (e.g. emission spectrometry or mass spectrometry).
a. For a calibration curve, make up 50 mL of a 10 mg/kg stock solution of Pb from Pb(NO3)2; the solution should contain 1% HNO3:
Calculate the amount of the lead salt that you have to dissolve;
how much HNO3 (65%) do you have to add (in g)?
b. Calibration standards need to be prepared from the stock solution described above, of the following concentrations in ppb (parts per billion as µg per kg solution): 0 - 0.1 - 0.3 - 0.5 - 1 - 5 - 10 - 100 – 500; each 50 mL of the standards are required; how much of the 10 mg/kg stock solution do you need per concentration?
c. Your calibration measurements are as follows:
C (ppb) counts
Produce a calibration graph (in Excel) with regression function
d. You have extracted 1.234 g of sediment in 10 mL of aqua regia. 1 mL of the extract was diluted to 10 mL and measured, to give an answer signal of 24 counts. Calculate the lead concentration in the original sample.
is it just me or these really badly worded?
for a) do i need to write a balanced reaction to start with?