Analytical Chemistry Final Exam 2025
Questions and Answers
A water sample analyzed in the lab had a calcium level of 193 ppm. What would
this concentration be if you expressed it as a molarity? (MW Ca = 40.078 g/mol) -
--Answer --4.82 mM
What is the molarity of a hydrochloric acid solution with 37.0 wt% and a density of
1.188 g/mL? - --Answer --12.1 M
Systematic error - --Answer --An error that can be determinate and be
correct with further analysis
Precision vs accuracy - --Answer --Precise: Closeness to each other;
Accuracy: closeness to the value
The titration of 50.00 (+/- .02) mL of a strong acid required 42.4 (+/- .2) mL of a
.1034 (+/- .0002) M strong base to reach the equivalence point. What is the
concentration of associated error of the strong acid? (sig figs) - --Answer --
.0877 (+/- .0004) M
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,You have the numbers: .1015, .0980, .1016, and .1017. What is the mean, standard
deviation and 95% confidence interval? (sig figs). There is one value that may be an
outlier. Calculate G and determine if the point should be rejected. - --
Answer --Mean: .1007; S= .002; 95%: .003; G calculated: 1.49 so we reject
the point (.0980)
Mean set 1: .02756 s set 1: .000488
Mean set 2: .02690 s set 2: .000406
Are the mean values significantly different at the 90% confidence level? N for both
sets is 5. - --Answer --The mean values are significantly different (standard
deviations are not significantly different)
You add 5.00 mL of waste water to a finally volume of 50 mL along with [Cu].
m=.0223 ppm-1 and b= .2168. What is the concentration of unknown in the
wastewater? - --Answer --97.2 ppm
When will you use the standard addition method? - --Answer --To overcome
the matrix effect
Confidence interval - --Answer --The interval in which you are a certain
percentage sure that the true value lies
What is the difference between standard addition and the internal standard
method? - --Answer --Standard addition: when you add a known quantity of
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, analyte to a mixture containing that analyte; Internal standard: a known amount of
a compound (different from the analyte) that is added to an unknown, tells us
about variations in the analyte signal due to random errors
What is the matrix effect? - --Answer --When something other than the
analyte (the matrix) causes a signal that interferes and causes a curve differing from
the standard curve
What is the pH of a 2.7 x 10^-2 M solution of LiOH? - --Answer --12.43
If the Ka for hypochlorous acid is 3.0 x 10^-8, what is the Kb? - --Answer --
3.3 x 10^-7
When is a buffer most resistant to pH change? - --Answer --When [acid] =
[conjugate base]
Under which conditions could activity be approximated as concentration (gamma
approx. 1)? - --Answer --Low ionic strength, large atomic radii, small ion
charge
If a solution was made by dissolving .1182 moles of acetic acid (CH3COOH, pKa
= 4.76) and .1670 moles of sodium acetate (CH3COONa) in 1.00 L of water, what
is the resulting pH? - --Answer --4.91
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Questions and Answers
A water sample analyzed in the lab had a calcium level of 193 ppm. What would
this concentration be if you expressed it as a molarity? (MW Ca = 40.078 g/mol) -
--Answer --4.82 mM
What is the molarity of a hydrochloric acid solution with 37.0 wt% and a density of
1.188 g/mL? - --Answer --12.1 M
Systematic error - --Answer --An error that can be determinate and be
correct with further analysis
Precision vs accuracy - --Answer --Precise: Closeness to each other;
Accuracy: closeness to the value
The titration of 50.00 (+/- .02) mL of a strong acid required 42.4 (+/- .2) mL of a
.1034 (+/- .0002) M strong base to reach the equivalence point. What is the
concentration of associated error of the strong acid? (sig figs) - --Answer --
.0877 (+/- .0004) M
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 1
,You have the numbers: .1015, .0980, .1016, and .1017. What is the mean, standard
deviation and 95% confidence interval? (sig figs). There is one value that may be an
outlier. Calculate G and determine if the point should be rejected. - --
Answer --Mean: .1007; S= .002; 95%: .003; G calculated: 1.49 so we reject
the point (.0980)
Mean set 1: .02756 s set 1: .000488
Mean set 2: .02690 s set 2: .000406
Are the mean values significantly different at the 90% confidence level? N for both
sets is 5. - --Answer --The mean values are significantly different (standard
deviations are not significantly different)
You add 5.00 mL of waste water to a finally volume of 50 mL along with [Cu].
m=.0223 ppm-1 and b= .2168. What is the concentration of unknown in the
wastewater? - --Answer --97.2 ppm
When will you use the standard addition method? - --Answer --To overcome
the matrix effect
Confidence interval - --Answer --The interval in which you are a certain
percentage sure that the true value lies
What is the difference between standard addition and the internal standard
method? - --Answer --Standard addition: when you add a known quantity of
....COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED...TRUSTED & VERIFIED 2
, analyte to a mixture containing that analyte; Internal standard: a known amount of
a compound (different from the analyte) that is added to an unknown, tells us
about variations in the analyte signal due to random errors
What is the matrix effect? - --Answer --When something other than the
analyte (the matrix) causes a signal that interferes and causes a curve differing from
the standard curve
What is the pH of a 2.7 x 10^-2 M solution of LiOH? - --Answer --12.43
If the Ka for hypochlorous acid is 3.0 x 10^-8, what is the Kb? - --Answer --
3.3 x 10^-7
When is a buffer most resistant to pH change? - --Answer --When [acid] =
[conjugate base]
Under which conditions could activity be approximated as concentration (gamma
approx. 1)? - --Answer --Low ionic strength, large atomic radii, small ion
charge
If a solution was made by dissolving .1182 moles of acetic acid (CH3COOH, pKa
= 4.76) and .1670 moles of sodium acetate (CH3COONa) in 1.00 L of water, what
is the resulting pH? - --Answer --4.91
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