CHEM 210 MODULE 6 EXAM SCRIPT 2026
FULL QUESTIONS AND SOLUTIONS
⩥ 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? Answer: 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?
Answer: 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? Answer:
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.. Answer: 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.. Answer: true
⩥ how many liters of a 2 M Ba(OH)2 are needed to titrate a 4 L solution
of 6 M H3PO4?. Answer: 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:. Answer: [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?. Answer: 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
FULL QUESTIONS AND SOLUTIONS
⩥ 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? Answer: 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?
Answer: 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? Answer:
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.. Answer: 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.. Answer: true
⩥ how many liters of a 2 M Ba(OH)2 are needed to titrate a 4 L solution
of 6 M H3PO4?. Answer: 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:. Answer: [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?. Answer: 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
