Analytical Chemistry

Question 1

This type of analysis means that the amount of some constituents was determined.

A. single-component analysis
B. ultimate analysis
C. partial analysis
D. complete analysis

Answer 1

C. partial analysis

Question 2

The molar mass of Na2B4O7*10H20 is

A. 383.43 mg/mmol
B. 201.22 mg/mmol
C. 381.42 mg/mmol
D. 269.32 mg/mmol

Answer 2

C. 381.42 mg/mmol

Question 3

How many grams of BaCl2:2H2O is needed to prepare 2.00 liters of 0.108 M BaCl2 solution?

A. 5280 mg
B. 52.8 g
C. 528 g
D. 52.80 g

Answer 3

B. 52.8 g

Question 4

Calculate the molality of 25.0 grams of KBr dissolved in 750.0 mL pure water.

A. 0.120 m
B. 0.410 m
C. 0.280 m
D. 0.310 m

Answer 4

C. 0.280 m

Question 5

These are solid materials added to promote fusing of metals.

A. solvents
B. precipitate
C. interferences
D. fluxes

Answer 5

D. fluxes

Question 6

The results of an analysis are 36.97 grams, compared with the accepted value of 37.06 grams. What is the relative error in parts per thousand?

A. 2.43 ppt
B. 3.04 ppt
C. 4.12 ppt
D. None of the above

Answer 6

A. 2.43 ppt

Question 7

Which in the following sets of data is more precise:

SET A (in mm): 821, 783, 834 and 855
SET B (in mm): 790, 810, 838 and 855 ?

A. Set B
B. Set A
C. Both Set A and B

Answer 7

A. Set B

Question 8

Which of the following is used to express the ppm of a solution?

A. kg analyte/kg sample
B. g analyte/g sample × 10
C. kg analyte/liter solution
D. mg analyte/liter solution x 10

Answer 8

B. g analyte/g sample × 10

Question 9

The initial and final reading of a buret in a given titration are 1.05 and 27.40 mL respectively. If the buret used has a standard deviation of + 0.05 mL, what is the volume of the titrant used and its corresponding deviation?

A. 26.35 (+0.07) ml
B. 24.10 (+0.04) ml
C. 20.32 (+0.07) ml
D. 25.30 (+0.05) ml

Answer 9

A. 26.35 (+0.07) ml

Question 10

Which is not true for peptization of colloids?

A. Electrolyte solution should volatilize when precipitate is dried.
B. Coagulated colloids revert to its original dispersed state.
C. Wash precipitate with distilled water.
D. Wash precipitate with a solution containing an electrolyte.

Answer 10

C. Wash precipitate with distilled water.

Question 11

A new gravimetric method is developed for Fe3+ determination and compared with the standard precipitation method with ammonia and weighing the Fe203. Based on the results, is the new gravimetric method comparable with the standard method?

New Method: 22.10 20.50 17.65 20.23 19.40 17.99
Standard: 18.89 19.20 19.00 19.70 19.40

A. The two methods are significantly different.
B. The two methods are not significantly different.

Answer 11

A. The two methods are significantly different.

Question 12

Analysis of carbonate in a sample of bottled water gives a mean of 11.8 ppm with a standard deviation of 0.70 pm for five replicates. If the standard value of carbonate in bottled water is <11.7 ppm, is there a need for product recall at 90% confidence level?

A. NO
B. YES

Answer 12

A. NO

Question 13

Calculate the molarity of a NaOH solution made by weighing 5.25 g of NaOH using a balance with a standard deviation of +0.05 g and dissolving it in enough water in a 500-mL volumetric flask with a standard deviation of +0.08-mL.

A. 0.2085 (+0.040) M
B. 0.2625 (+0.042) M
C. 0.2021 (+0.042) M
D. 0.2021 (+0.040) M

Answer 13

B. 0.2625 (+0.042) M

Question 14

In the analysis of 0.7011 g of an impure chloride containing sample, 0.9805 g of AgCl were precipitated. What is the percentage by mass chloride in the sample?

A. 28.85%
B. 34.59%
C. 25.45%
D. 78.14%

Answer 14

B. 34.59%

Question 15

A 0.4054 g solid organic sample containing covalently bound bromide and no other halogens was placed in a porcelain crucible with about one gram of fresh sodium metal. In a process known as sodium fusion, the mixture was heated in a furnace to 450°C which charred and vaporized the organic portion of the molecule and converted the covalent bromide into sodium bromide. Excess sodium was decomposed by adding small portions of water which also dissolved the sodium bromide. The clear solution was quantitatively transferred to a beaker, acidified with dilute nitric acid, and diluted to about 50 mL. A 6 mL quantity of 0.1 M AgNO3 was added to the solution and the mixture heated to about 60°C for an hour to age and digest the precipitate. After filtering, the mass of the silver bromide produced was determined to be 37.8 mg. What is the percentage by mass bromine in the organic compound?

A. 4.15%
B. 3.00%
C. 2.15%
D. 3.97%

Answer 15

D. 3.97%

Question 16

A 0.4960 g sample of a CaCO3 is dissolved in an acidic solution. The calcium is precipitated as CaC2O4.H2O and the dry precipitate is found to weigh 0.6186 g. What is the percentage of CaO in the sample?

A. 41.89%
B. 52.10%
C. 47.78%
D. 30.66%

Answer 16

C. 47.78%

Question 17

0.8 g sample contains has been dissolved. The sulfur is precipitated as BaSO4. If the weight of the precipitate is 0.3g calculate the percentage of sulfur in the sample?

A. 6.52%
B. 7.02%
C. 4.10%
D. 5.20%

Answer 17

D. 5.20%

Question 18

Calculate the concentration of a solution of a species which has an absorbance of 0.494 at 525 nm if the cell path length is 1.00 cm and the molar absorptivity of the species is 1.38 × 10^4.

A. 3.58 X 10^-5 M
B. 3.02 X 10^-5 M
C. 3.16 X 10^-5 M
D. 3.28 X 10^-5 M

Answer 18

A. 3.58 X 10^-5 M

Question 19

A 50.00 mL sample of a sodium hydroxide solution is titrated with a 1.605 M solution of sulfuric acid. The titration requires 24.09 mL of the acid solution to reach the equivalence point. What is the molarity of the base solution?

H2SO4(aq) + 2NaOH(aq) → Na2SO4(aq) + 2H2O(l)

A. 1.623 M NaOH
B. 1.547 M NaOH
C. 1.451 M NaOH
D. 1.501 M NaOH

Answer 19

B. 1.547 M NaOH

Question 20

It is an ultrapure compound that serves as the reference material for a titrimetric method of analysis.

A. primary standard
B. none of the above
C. secondary standard
D. standard solution

Answer 20

A. primary standard