Chem 4224 NAME
Fall 2005
HW 1
1. Describe how you can prepare 100.0 ml of a 1.00 ppb solution of aqueous Cr
+6
using
1.00 ml transfer pipets, 100.00 ml volumetric flasks and a mass of potassium
dichromate greater than 0.1000 g.
2. Assuming the density a 10% (w/w) aqueous nitric acid solution is 1.068 g/ml,
determine if it can be used as a stock solution to prepare 100.0 ml of pH = 0.50 HCl
solution? If so, how determine the ml of stock needed to prepare this solution.
3. Calculate the mass (gram) of solute require to prepare 250.0 ml of the following
aqueous solutions:
0.100 M potassium hydrogen phthalate
2.00 ppm (w/v) Na
+
using sodium carbonate
2.50 ppb (w/v) Cr
+3
using chromium(III)nitrate
4. Explain the difference between 1) TC and TD, and 2) class A and class B volumetric
glassware.
5. The percent alcohol of a blood sample has been determined to be 0.084, 0.089, 0.079.
Determine the 95% confidence limit for the mean, and provide a written
interpretation of this quantity.
6. A new method of determining sulfur in kerosene is tested on a sample known to
contain 0.123% S. The results were % S = 0.112, 0.118, 0.115, 0.119. Do the data
indicate the presence of a bias in the method at the 95% confidence level?
7. Determine the slope, intercept, R
2
, standard error of the slope, and standard error of
the intercept of the following data.
Calibration Data for the Chromatographic
Determination of Isooctane in a Hydrocarbon Mixture
Standard
solution Mole % Isooctane Peak Area
1 0.352 1.09
2 0.803 1.78
3 1.08 2.60
4 1.38 3.03
5 1.75 4.01
8. A solution of sodium chloride is prepared by dissolving 4.553 ±0.001 g of NaCl in
sufficient deionized water to make 100.0 ±0.1 ml of solution. Calculate the molarity
