Analytical Chemistry Fundamentals

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What is the primary goal of analytical chemistry?

To discover new principles of measurements

To create new laser and microchip devices

To improve means of measuring chemical composition (correct)

To develop new materials

What does qualitative analysis provide?

New principles of measurements

Reliability of existing techniques

Numerical information about species

Information about the identity of species (correct)

What do analytical chemists adapt to new kinds of materials?

New principles of measurements

Proven methodologies (correct)

Reliability of existing techniques

Laser and microchip devices

Why do analytical chemists work to improve existing techniques?

To meet demands for better chemical measurements Signup and view all the answers

What is the minimum number of standards required to produce a calibration curve if linearity is satisfactory?

Five Signup and view all the answers

What is an example of a major discovery utilized by analytical chemists?

Laser Signup and view all the answers

What is the correlation coefficient of the linearity statistics?

0.9978 Signup and view all the answers

What is the range of the linearity in the given validation table?

0.005 – 0.040 mg/mL Signup and view all the answers

What is the definition of linearity based on?

Samples with varying concentrations and the calculation of the regression of results Signup and view all the answers

Why are more standards necessary when linearity is unsatisfactory?

To compensate for the non-linear relationship between signal and concentration Signup and view all the answers

What is sensitivity equivalent to in the context of linearity?

The proportionality constant, kA Signup and view all the answers

What is ruggedness in the context of analytical methods?

The degree of reproducibility obtained under a variety of conditions Signup and view all the answers

What is accuracy in the context of analytical methods?

The combination of precision and correctness Signup and view all the answers

What is the primary difference between repeatability and reproducibility?

Repeatability is within a laboratory, while reproducibility is between laboratories Signup and view all the answers

What is validation of testing methods used for?

To determine the accuracy of an analytical method Signup and view all the answers

What is the term for random and systematic deviations from the true value?

Uncertainty Signup and view all the answers

What is the purpose of using certified reference materials (CRMs) in analytical methods?

To improve the accuracy of an analytical method Signup and view all the answers

What is a condition for the determination of the recovery rate?

The analytical substance needs to be added in the form in which it occurs in nature Signup and view all the answers

How can reproducibility be proven externally?

Through participation in proficiency testing schemes or participation in interlaboratory comparisons Signup and view all the answers

What is a characteristic of method accuracy?

Correctness Signup and view all the answers

What type of test method determines true values?

Methods which are determining true values Signup and view all the answers

What is a procedure for method validation?

The Analysis of Standard Reference Materials Signup and view all the answers

What is a characteristic of method precision?

Repeatability Signup and view all the answers

What is the purpose of using selective chelating reagents in colorimetric analysis?

To minimize interference and optimize color development Signup and view all the answers

What is a common source of random errors in the gravimetric determination of sulfate content?

Fluctuations in temperature affecting the rate of precipitation Signup and view all the answers

What is the purpose of using excess barium chloride in the gravimetric determination of sulfate content?

To ensure complete precipitation of sulfate ions Signup and view all the answers

What is the formula used to calculate the confidence interval for the actual pH value?

x̄ ± t(s/√n) Signup and view all the answers

What is the purpose of performing blank corrections in colorimetric analysis?

To correct for errors in measurement of reagents Signup and view all the answers

What is the effect of incomplete precipitation of sulfate ions on the gravimetric determination of sulfate content?

It results in a systematic error, causing an underestimation of sulfate content Signup and view all the answers