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The volumes of a solution containing 1.10 ppm of Zn2+ shown in the table werepipetted
Chapter 15, Problem 15-8(choose chapter or problem)
The volumes of a solution containing 1.10 ppm of \(\mathrm{Zn}^{2+}\) shown in the table were pipetted into separatory funnels, each containing 5.00 mL of an unknown zinc solution. Each was extracted with three 5-mL aliquots of \(\mathrm{CCl}_{4}\), containing an excess of 8-hydroxyquinoline. The extracts were then diluted to 25.0 mL and their fluorescence measured with a fluorometer. The results were the following:
\(\begin{array}{cc}
\begin{array}{c}
\text { Volume Std. } \\
\mathbf{Z n}^{2+}, \mathbf{m L}
\end{array} & \begin{array}{c}
\text { Fluorometer } \\
\text { Reading }
\end{array} \\
\hline 0.000 & 6.12 \\
4.00 & 11.16 \\
8.00 & 15.68 \\
12.00 & 20.64 \\
\hline
\end{array}\)
(a) Construct a working curve from the data.
(b) Calculate a linear least-squares equation for the data.
(c) Calculate the standard deviation of the slope and intercept and the standard deviation about regression.
(d) Calculate the concentration of zinc in the sample.
(e) Calculate a standard deviation for the result in part (d).
Questions & Answers
QUESTION:
The volumes of a solution containing 1.10 ppm of \(\mathrm{Zn}^{2+}\) shown in the table were pipetted into separatory funnels, each containing 5.00 mL of an unknown zinc solution. Each was extracted with three 5-mL aliquots of \(\mathrm{CCl}_{4}\), containing an excess of 8-hydroxyquinoline. The extracts were then diluted to 25.0 mL and their fluorescence measured with a fluorometer. The results were the following:
\(\begin{array}{cc}
\begin{array}{c}
\text { Volume Std. } \\
\mathbf{Z n}^{2+}, \mathbf{m L}
\end{array} & \begin{array}{c}
\text { Fluorometer } \\
\text { Reading }
\end{array} \\
\hline 0.000 & 6.12 \\
4.00 & 11.16 \\
8.00 & 15.68 \\
12.00 & 20.64 \\
\hline
\end{array}\)
(a) Construct a working curve from the data.
(b) Calculate a linear least-squares equation for the data.
(c) Calculate the standard deviation of the slope and intercept and the standard deviation about regression.
(d) Calculate the concentration of zinc in the sample.
(e) Calculate a standard deviation for the result in part (d).
ANSWER:Step 1 of 7
(a)
The chart for the fluorometer readings versus the volume of the standard solution is given in the table below
\(\begin{array}{|l|l|}
\hline \text { Volume }(\mathrm{ml}) & \begin{array}{l}
\text { Fluorometer } \\
\text { Reading }
\end{array} \\
\hline 0 & 6.12 \\
\hline 4 & 11.16 \\
\hline 8 & 15.68 \\
\hline 12 & 20.64 \\
\hline
\end{array}\)