[an error occurred while processing this directive] instrumental techniques

practice exam IA
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1. Which of the following statements about the 'true' and 'best estimate' standard deviations is FALSE?
The standard deviation is the square root of the variance.
The 'best estimate' standard deviation applies only to small sample sizes.
The number of degrees of freedom for the 'best estimate' standard deviation is N-1.
The population mean is used to calculate the 'best estimate' standard deviation.
Both standard deviations are a measure of precision, but not a measure of accuracy.
2. Sensitivity is the
ability to resolve the analyte from other species
response per unit amount of analyte
extent to which the analyte is destroyed by the analytical technique
number of moles of analyte that produces a maximum instrument response
slope of a titration curve
3. One µL is equivalent to
100 nL
0.01 mL
 		0.001 cm3
0.000001 m3
 		106 cm3
0.001 cL
4. The density of mercury is 13.6 g/mL. How many pounds does one quart of mercury weigh? (1 pound is 454 g, 4 quarts are 3.7854 liters.)
(13.6 x 1000 x 4)/(454 x 3.7854)
(13.6 x 454 x 1000 x 3.7854)/4
(13.6 x 3.7854)/(454 x 1000 x 4)
 		(13.6 x 1000 x 3.7854)/(454 x 4)
(13.6 x 454 x 3.7854)/(1000 x 4)
none of these
5. Which of the following measurements are equivalent?
none of these
10 nL and 1000 pL
 		40 km and 40000 cm
10 micrograms and 0.1 milligrams
 		all of these
0.01 mm and 1 x 10-3 cm
6. How many grams are in 10.0 mmol of KI (molar mass 166.01 g)?
1.66 x 106 g 1.66 g 6.02 x 10-3 g 16.6 g 16.6 x 103 g none of these
7. How many grams of pure NaCl are required to make 500 mL of 2.00 M NaCl solution (molar mass 58.4 g)?
5.84 x 104 g 29.2 g 117 g 3.42 x 10-2 g 58.4 g 0.117 g
8. The first step in an analysis of water for dissolved oxygen involves the reaction
4 Mn(OH)2(aq) + O2(aq) + 2 H2O(aq) = 4 Mn(OH)3(s)
.If treatment of 1.000 L of water from a creek with excess Mn(OH)2(aq) produces 0.103 g of Mn(OH)3, how many grams of O2(aq) does one liter of the water contain? The molecular weights of Mn(OH)2 and Mn(OH)3 are 88.94 and 105.94, respectively.
(0.103 x 105.94 x 32)/4
(0.103 x 32)/(105.94 x 4)
(0.103 x 4 x 32)/105.94
 		(0.103 x 16)/(105.94 x 4)
(0.103 x 32)/(88.94 x 4)
(0.103 x 16)/(88.94 x 4)
9. The following concentrations of mercury were found in the blood of alewife taken from a river: 1.2 ppm, 1.3 ppm, 1.4 ppm, 2.5 ppm, 0.9 ppm, 1.5 ppm. If the Q test is applied to this data, which of the following is true?
0.9 ppm can be rejected at 95% confidence, but not at 99% confidence.
2.5 ppm can be rejected with 99% confidence.
2.5 ppm can be rejected at 95% confidence, but not at 99% confidence.
0.9 ppm can be rejected with 99% confidence.
both 2.5 ppm and 0.9 ppm can be rejected with 95% confidence.
none of the data can be rejected.
10. Which of the following is NOT true of gravimetric methods?
high accuracy for macro samples
easily automated
high precision for macro to micro samples
can be used for sulfates and chlorides
include precipitation, volatilization, and electrodeposition methods
11. Which of the following conditions will lead to smaller precipitate particle size in a precipitation reaction?
a large number of fine, suspended contaminant particles
a low degree of supersaturation
a hot reaction mixture
slow addition of the precipitating agent
digestion of the reaction mixture
addition of electrolytes
12. Which of the following will minimize coprecipitation?
use a precipitating agent with low selectivity
form the precipitate in a cold, concentrated solution
wash the precipitate with a volatile electrolyte solution
form the precipitate as rapidly as possible
avoid digestion of the reaction mixture
wash the precipitate with distilled water
13. 25.00 mL of an NaOH solution is standardized using 47.13 mL of 0.1613 M H2SO4 with phenolphthalein indicator. Which of the following statements is true?
The equivalence point is 47.13 mL of H2SO4 solution.
The H2SO4 is a secondary standard.
The base solution is about half the molarity of the acid solution.
The phenolphthalein turns from blue to yellow at the equivalence point.
The buret had marks that were 0.01 mL apart.
14. How many milliliters of 0.100 M AgNO3 will be required to completely react with 10.0 mL of a 0.200 M KCl solution?
10.0 mL 40.0 mL 20.0 mL 0.020 mL 200. mL none of these
15. The total alkalinity of an antacid tablet is determined by pipetting 25.00 mL of 0.2000 M HCl on a crushed 2.000g sample of the tablet. When the reaction is complete, the mixture is then titrated with 10.00 mL of 0.1000 M NaOH. The alkalinity of the tablet in moles of HCl neutralized per gram of antacid is
none of these 0.004 0.005 0.001 0.006 0.002
16. The pH after adding 10.0 mL of 0.1000 M NaOH solution to 50.0 mL 0f 0.100 M HCl solution is
4.10 6.66 x 10-2 2.40 1.18 3.60 none of these
17. The pH after adding 10.0 mL of 0.1000 M NaOH solution to 50.0 mL 0f 0.100 M HC2H3O2 solution (Ka=1.75 x 10-5 ) is
5.36 1.18 2.40 4.76 4.16 none of these
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