Part A. absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 ?L of the sample and injecting it into a cuvette already containing 2.00 mL of water (total volume is 2.00 mL + 100.0 ?L). The absorbance value of the diluted solution corresponded to a concentration of 6.28Ã10?6 M . What was the concentration of the original solution? express the concentration to three significant figures with the appropriate units.
Part B. Molar Mass = Mass solute (in g)Moles solute
In order to prepare a certain volume of solution with a desired concentration, you would need to determine the required mass of solute. What mass of CaI2 would you need to prepare a 100. mL solution at a concentration of 0.420 M ? Express the mass in grams to three significant figures.
Part c.
Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCN for a person weighing 145 lb (65.8 kg ) is 7.27Ã10?3 mol .
What volume of a 0.0820 M KCN solution contains 7.27Ã10?3 mol of KCN?
Express the volume to three significant figures and include the appropriate units.
Part A. absorbance of a cationic iron(II) sample solution was measured in a spectrophotometer, but the instrument returned an error because the absorbance was too high. The sample was then diluted by using a pipette to take 100.0 ?L of the sample and injecting it into a cuvette already containing 2.00 mL of water (total volume is 2.00 mL + 100.0 ?L). The absorbance value of the diluted solution corresponded to a concentration of 6.28Ã10?6 M . What was the concentration of the original solution? express the concentration to three significant figures with the appropriate units.
Part B. Molar Mass = Mass solute (in g)Moles solute
In order to prepare a certain volume of solution with a desired concentration, you would need to determine the required mass of solute. What mass of CaI2 would you need to prepare a 100. mL solution at a concentration of 0.420 M ? Express the mass in grams to three significant figures.
Part c.
Potassium cyanide is a toxic substance, and the median lethal dose depends on the mass of the person or animal that ingests it. The median lethal dose of KCN for a person weighing 145 lb (65.8 kg ) is 7.27Ã10?3 mol .
What volume of a 0.0820 M KCN solution contains 7.27Ã10?3 mol of KCN?
Express the volume to three significant figures and include the appropriate units.
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