CHEM 210 MODULE 6 EXAMINATION TEST
2026 COMPLETE QUESTIONS AND
CORRECT ANSWERS
⩥ statistical interference assesses whether an observed phenomenon in
the data can reasonably be attributed to chance or not. Answer: 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?. Answer: (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?. Answer: 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?. Answer: 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?. 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
2026 COMPLETE QUESTIONS AND
CORRECT ANSWERS
⩥ statistical interference assesses whether an observed phenomenon in
the data can reasonably be attributed to chance or not. Answer: 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?. Answer: (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?. Answer: 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?. Answer: 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?. 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
