CHEM 210 TEST 7 UPDATED ACTUAL EXAM QUESTIONS CORRECT ANSWERS GRADED A
PLUS
CHEM 210 TEST 7 2026/2027 Questions and
Answers Verified Solutions Latest Update
Question:
what is the best way to characterize the random error present in a measurement?
Answer:
take replicate measurements of your analytes and using the standard deviation and a t-table specify
an error bar with a confidence limit
Question:
statistical interference assesses whether an observed phenomenon in the data can reasonably be
attributed to chance or not.
Answer:
true
Question:
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
Question:
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
, Question:
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
Question:
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
Question:
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
Question:
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:
PLUS
CHEM 210 TEST 7 2026/2027 Questions and
Answers Verified Solutions Latest Update
Question:
what is the best way to characterize the random error present in a measurement?
Answer:
take replicate measurements of your analytes and using the standard deviation and a t-table specify
an error bar with a confidence limit
Question:
statistical interference assesses whether an observed phenomenon in the data can reasonably be
attributed to chance or not.
Answer:
true
Question:
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
Question:
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
, Question:
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
Question:
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
Question:
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
Question:
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:
