CHEM 210 Final Exam Questions and Correct Answers Latest Update (2025-2026) Already Passed
if the p-value is greater than 0.1, we generally conclude the data are consistent with the null hypothesis
- Answers true
what is the best way to characterize the random error present in a measurement? - Answers take
replicate measurements of your analytes and using the standard deviation and a t-table specify an error
bar with a confidence limit
statistical interference assesses whether an observed phenomenon in the data can reasonably be
attributed to chance or not - Answers true
suppose we collected a sample size n = 100 from some population and used the data to calculate a 95%
confidence interval for the population mean. now suppose we are going to increase the sample size to n
= 300. keeping all else constant, which of the following would we expect to occur as a result of
increasing the sample size? - Answers (1) the standard error would decrease, (2) the margin of error
would decrease
in designing a clinical trial where each subject receives both a placebo and a proposed treatment, what
statistical test would be most appropriate? - Answers paired t-test
an atomic absorption analysis is to be done on the calcium in a sample of powdered milk. a 12.55 gram
sample of the powder is wet ashed in nitric acid and diluted to 50.00 mL with distilled water. a 1.00 mL
aliquot of this is transferred to a 50.00 mL solution using EDTA. using a wavelength of 422.6 nm in an
atomic absorption experiment, this diluted sample showed an absorbance of 0.375. a standard calcium
sample (treated the same way) with a known concentration of 20.0 ppm provided an absorbance of
0.859. what is the ppm of calcium in the powdered milk? - Answers 437 ppm
in a 3 step serial dilution: the first dilution is 1/10, the second dilution is 1/5, and the third dilution is 1/4.
what is the total dilution factor of this 3 step serial dilution procedure? - Answers 200
a solution was prepared by mixing 10.00 mL of unknown (X) with 5.00 mL of standard (S) containing 8.24
ug/mL and diluting the mixture to 50.0 mL. the measured signal areas from an atomic absorption
spectrometer of X:S was 1.690:1.000. in a separate experiment in which the concentrations of X and S
were equal, the measured signal areas of X:S was 0.930:1.000. the concentration of X in the unknown is?
- Answers 7.49 ug/mL
you set up a 10 tube Minimum Inhibitory Concentration test where the concentration of the antibiotic in
each tube is a 1:2 dilution of the previous tube. if the concentration of the antibiotic tube 1 is 3200
ug/mL, what is the concentration of the antibiotic in tube 6? - Answers 100 ug/mL
solution: (1/2)^5 x 3200 = 100
, to measure the Ca in breakfast cereal, 0.561 g of crushed Cheerios was digested at 600*C in air for 2
hours. the residue was dissolved in 6 M HCl, quantitatively transferred to a volumetric flask and dilution
to 100.0 mL. then 5.00-mL aliquots were transferred to 50.0-mL volumetric flasks. each was treated with
standard Ca2+ ion solution (20.0 ppm), diluted to volume with H2O, and analyzed by flame atomic
absorption. a graph was constructed from the readings. use this graph to determine the wt% Ca in
Cheerios. - Answers 0.4%
the pH of the titration solution at the equivalence point is 9.45. this is consistent with titration of a weak
acid with strong base. - Answers true
how many liters of a 2 M Ba(OH)2 are needed to titrate a 4 L solution of 6 M H3PO4? - Answers 18 L
solution: (4 x X) = (4 x 18)
the charge balance equation for a solution containing H2O, H+, OH-, Ca2+, K+, C2H5OH, CrO4(2-), and Cl-
is: - Answers [H+] + 2[Ca2+] + [K+] = [OH-] + [Cl-] + 2[CrO4(2-)]
what is the [H3O+] of a 2 M aqueous solution of a weak acid HXO2 with Ka = 3.2 x 10^-5? - Answers 8.0 x
10^-3 M
glutamic acid is an amino acid consisting of 2 carboxylic acid functional groups and an amine functional
group. pKas are listed as 2.19, 4.25, and 9.67. at pH 7, the charge on the glutamic molecule is? - Answers
-1
which of the following is NOT a characteristic of an amphoteric species? - Answers amphoteric species
are always nonpolar
all of the following are TRUE for activities and activity coefficients, except... - Answers as ionic strength
increases, the value of the activity coefficient increases
glutamic acid is an amino acid consisting of 2 carboxylic acid functional groups and an amine functional
group. pkas are listed as 2.19, 4.25, and 9.67. the approximate pH of 0.025 M HL- is? - Answers 6.96
solution: (1/2) x (4.25 + 9.67)
what is the pH of a solution with an ammonium concentration of 70 mM and an ammonia concentration
of 712 mM? (pKb of ammonia is 3.45) - Answers 11.55
the amino acid valine has pKa1 = 2.29 and pKa2 = 9.72. what is the principal species at 6.00? - Answers
HA-
the titration solution consists of essentially pure weak acid... - Answers at the equivalence point of a
weak acid/strong base titration
if the p-value is greater than 0.1, we generally conclude the data are consistent with the null hypothesis
- Answers true
what is the best way to characterize the random error present in a measurement? - Answers take
replicate measurements of your analytes and using the standard deviation and a t-table specify an error
bar with a confidence limit
statistical interference assesses whether an observed phenomenon in the data can reasonably be
attributed to chance or not - Answers true
suppose we collected a sample size n = 100 from some population and used the data to calculate a 95%
confidence interval for the population mean. now suppose we are going to increase the sample size to n
= 300. keeping all else constant, which of the following would we expect to occur as a result of
increasing the sample size? - Answers (1) the standard error would decrease, (2) the margin of error
would decrease
in designing a clinical trial where each subject receives both a placebo and a proposed treatment, what
statistical test would be most appropriate? - Answers paired t-test
an atomic absorption analysis is to be done on the calcium in a sample of powdered milk. a 12.55 gram
sample of the powder is wet ashed in nitric acid and diluted to 50.00 mL with distilled water. a 1.00 mL
aliquot of this is transferred to a 50.00 mL solution using EDTA. using a wavelength of 422.6 nm in an
atomic absorption experiment, this diluted sample showed an absorbance of 0.375. a standard calcium
sample (treated the same way) with a known concentration of 20.0 ppm provided an absorbance of
0.859. what is the ppm of calcium in the powdered milk? - Answers 437 ppm
in a 3 step serial dilution: the first dilution is 1/10, the second dilution is 1/5, and the third dilution is 1/4.
what is the total dilution factor of this 3 step serial dilution procedure? - Answers 200
a solution was prepared by mixing 10.00 mL of unknown (X) with 5.00 mL of standard (S) containing 8.24
ug/mL and diluting the mixture to 50.0 mL. the measured signal areas from an atomic absorption
spectrometer of X:S was 1.690:1.000. in a separate experiment in which the concentrations of X and S
were equal, the measured signal areas of X:S was 0.930:1.000. the concentration of X in the unknown is?
- Answers 7.49 ug/mL
you set up a 10 tube Minimum Inhibitory Concentration test where the concentration of the antibiotic in
each tube is a 1:2 dilution of the previous tube. if the concentration of the antibiotic tube 1 is 3200
ug/mL, what is the concentration of the antibiotic in tube 6? - Answers 100 ug/mL
solution: (1/2)^5 x 3200 = 100
, to measure the Ca in breakfast cereal, 0.561 g of crushed Cheerios was digested at 600*C in air for 2
hours. the residue was dissolved in 6 M HCl, quantitatively transferred to a volumetric flask and dilution
to 100.0 mL. then 5.00-mL aliquots were transferred to 50.0-mL volumetric flasks. each was treated with
standard Ca2+ ion solution (20.0 ppm), diluted to volume with H2O, and analyzed by flame atomic
absorption. a graph was constructed from the readings. use this graph to determine the wt% Ca in
Cheerios. - Answers 0.4%
the pH of the titration solution at the equivalence point is 9.45. this is consistent with titration of a weak
acid with strong base. - Answers true
how many liters of a 2 M Ba(OH)2 are needed to titrate a 4 L solution of 6 M H3PO4? - Answers 18 L
solution: (4 x X) = (4 x 18)
the charge balance equation for a solution containing H2O, H+, OH-, Ca2+, K+, C2H5OH, CrO4(2-), and Cl-
is: - Answers [H+] + 2[Ca2+] + [K+] = [OH-] + [Cl-] + 2[CrO4(2-)]
what is the [H3O+] of a 2 M aqueous solution of a weak acid HXO2 with Ka = 3.2 x 10^-5? - Answers 8.0 x
10^-3 M
glutamic acid is an amino acid consisting of 2 carboxylic acid functional groups and an amine functional
group. pKas are listed as 2.19, 4.25, and 9.67. at pH 7, the charge on the glutamic molecule is? - Answers
-1
which of the following is NOT a characteristic of an amphoteric species? - Answers amphoteric species
are always nonpolar
all of the following are TRUE for activities and activity coefficients, except... - Answers as ionic strength
increases, the value of the activity coefficient increases
glutamic acid is an amino acid consisting of 2 carboxylic acid functional groups and an amine functional
group. pkas are listed as 2.19, 4.25, and 9.67. the approximate pH of 0.025 M HL- is? - Answers 6.96
solution: (1/2) x (4.25 + 9.67)
what is the pH of a solution with an ammonium concentration of 70 mM and an ammonia concentration
of 712 mM? (pKb of ammonia is 3.45) - Answers 11.55
the amino acid valine has pKa1 = 2.29 and pKa2 = 9.72. what is the principal species at 6.00? - Answers
HA-
the titration solution consists of essentially pure weak acid... - Answers at the equivalence point of a
weak acid/strong base titration
