Detection limit. In spectrophotometry, we measure the concentration of analyte by its absorbance of light. A lowconcentration
sample was prepared, and nine replicate measurements
gave absorbances of 0.004 7, 0.005 4, 0.006 2,
0.006 0, 0.004 6, 0.005 6, 0.005 2, 0.004 4, and 0.005 8 in a
1.000-cm cell. Nine reagent blanks gave values of 0.000 6,
0.001 2, 0.002 2, 0.000 5, 0.001 6, 0.000 8, 0.001 7, 0.001 0,
and 0.001 1.
(a) Find the absorbance detection limit with Equation 5-2.
(b) The calibration curve is a graph of absorbance versus
concentration in a cell with a pathlength of 1.000 em. Absorbance
is a dimensionless quantity. The slope of the calibration
curve is m = 2.24 X 104 M-1• Find the concentration detection
limit with Equation 5-4.

Consider three unlabeled bottles, each contain small pieces of one of the following metals. - magnesium - sodium - silver the following reagents are used for identifying the metals. - pure water - a solution of 1.0 molar hcl - a solution of concentrated hno3 (a) which metal can be easily identified because it is much softer than the other two? describe a chemical test that distinguishes this metal from the other two, using only one of the reagents above. write a balanced chemical equation for the reaction that occurs. (b) one of the other two metals reacts readily with the hcl solution. identify the metal and write the balanced chemical equation for the reaction that occurs when this metal is added to the hcl solution. use the table of standard reduction potentials (attached) to account for the fact that this metal reacts with hcl while the other does not. (c) the one remaining metal reacts with the concentrated hno3 solution. write a balanced chemical equation for the reaction that occurs. (d) the solution obtained in (c) is diluted and a few drops of 1 m hcl is added. describe what would be observed. write a balanced chemical equation for the reaction that occurs.

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0

Calculate the molarity of each of the following solutions. part a) 0.12 mol of lino3 in 5.5 l of solution part b) 60.7 g c2h6o in 2.48 l of solution part c) 14.2 mg ki in 100 ml of solution