Question

In this lab, you will carry out dilutions using a dropper to get qualitative information about metal/ligand ratios. Two drops of hydroxylamine solution are placed in a 0.50-mL well. Then eight drops of ligand solution, and 1 drops of 5 mg L-1 iron solution are added. How many nanomoles of iron are in the well? Useful conversion factors: There are about 20 drops in 1 mL. 1 nanomole = 1x10-9 moles

Answer 1

The drops in 1mL = 20

a) two drops of hydroxylamine solution are placed in 0.5mL well

b) 1 drop of 5mg/L iron solution are added

c) eight drops of ligand solution

The total volume = 2 drops + 1 drop + 8 drops = 11 drops

20 drops = 1mL

11 drops = 0.55mL

a) Amount of iron solution = 1 drop = 0.05mL

concentration = 5mg / L = 5mg / 1000mL = 5 X 10^-3 mg/ mL =

so amount in 0.05mL = 5X 10^-3 X 0.05 mg = 25 X 10^-5 mg = 25 X 10^-8 g = 250 nanograms

moles = mass / atomic weight of iron = 250 nanogram / 56 = 4.46 nanograms