Book cover for Chemistry

Chemistry

Catherine E. Housecroft, Edwin C. Constable

ISBN #9780273715450

4th Edition

995 Questions

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Homework Questions

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Summary

Learning Objectives

Key Concepts

Example Problems

Explanations

Common Mistakes

Summary

This chapter on 'Chemistry in the Workplace' explores a range of chemical analysis techniques applied in diverse real-world scenarios. Topics include forensic analysis of gunshot residues, determination of water content in foodstuffs, detection of melamine in pet food and powdered milk, environmental toxin analysis, and quality control using advanced techniques like GC-MS, HPLC, capillary zone electrophoresis, and atomic absorption spectroscopy. The chapter emphasizes the importance of precision, sample preparation, and methodological accuracy in ensuring product safety and regulatory compliance across various industries.

Learning Objectives

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Key Concepts

CONCEPT

DEFINITION

Acyclic and cyclic alkanes

A discussion of both open?chain (acyclic) and ring (cyclic) saturated hydrocarbons, emphasizing their structural features, nomenclature, conformational behavior (including ring strain and conformation), and the processes used in their interconversion and synthesis.

Example Problems

Example 1

The water content of a petroleum sample is thought to be about $0.08 \mathrm{mg}$ per g. Explain how you would check this water content, and include details of the reactions occurring during the analysis.

Example 2

Honey usually contains about $17 \%$ water. Explain how you would confirm that a batch of honey for sale commercially had not been adulterated with water. Include details of the reactions occurring during the analysis.

Example 3

Draw a diagram to show the components of a GC-MS instrument, and give a brief explanation of the role of each component.

Example 4

LC with UV-detection $(\lambda \approx 220 \mathrm{nm})$ is routinely used to separate herbicides such as atrazine and simazine: The presence of herbicides in drinking water is controlled by legislation, and the WHO recommended limit for each of atrazine and simazine is $0.002 \mathrm{mg} \mathrm{dm}^{-3} .$ The following questions relate to the LC-MS analysis of drinking water for atrazine and simazine. (a) What is meant by "UV-detection"? Suggest the origin of the absorption at $220 \mathrm{nm}$ (b) Internal standards of fully deuterated atrazine and simazine are used. Explain why they are added to all samples during both calibration and analyte runs. (c) How would you calibrate the LC instrument (bearing in mind the WHO recommended limits for atrazine and simazine) and how would you determine the concentrations of the herbicides in a sample of drinking water? (d) Why does the analyst record the mass spectrum in addition to LC data for each analyte?

Example 5

What is the value of $n$ in each of the following: (a) $1 \mathrm{fg}=10^{n} \mathrm{g} ;$ (b) $1 \mathrm{pg}=10^{n} \mathrm{g} ;$ (c) $1 \mathrm{mg}=10^{n} \mathrm{g}$ (d) $1 \mu g=10^{n} g ?$

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Step-by-Step Explanations

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Common Mistakes

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