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Chapter 2. Understanding Measurement

Enhanced Introductory College Chemistry

by Gregory Anderson; Caryn Fahey; Jackie MacDonald; Adrienne Richards; Samantha Sullivan Sauer; J.R. van Haarlem; and  David Wegman;

Chapter Contents

Except where otherwise noted, this OER is licensed under CC BY 4.0

Please visit the web version of Enhanced Introductory College Chemistry to access the complete book, interactive activities and ancillary resources.

In this chapter, you will learn about

  • Exact and uncertain measurements
  • Numerical prefixes and equalities
  • Analyzing numerical problems

To better support your learning, you should be familiar with the following concepts before starting this chapter:

  • The metric system
  • Basics of arithmetic

Measurements provide the macroscopic information that is the basis of most of the hypotheses, theories, and laws that describe the behaviour of matter and energy in both the macroscopic and microscopic domains of chemistry. Every measurement provides three kinds of information: the size or magnitude of the measurement (a number); a standard of comparison for the measurement (a unit); and an indication of the uncertainty of the measurement. While the number and unit are explicitly represented when a quantity is written, the uncertainty is an aspect of the measurement result that is more implicitly represented and will be discussed later.

Scientists in Action: Twelve Women in Chemistry

Carolyn Bertozzi – Chemical BiologistBertozzi researches the role of sugars on the surface of cells in diseases such as cancer, and develops technology to advance biomedical research. Ada Yonath – Crystallographer Yonath’s research on the structure of the ribosome, which helps cells build proteins, won her a Nobel Prize. She also worked on modes of action of antibiotics. Susan Solomon – Atmospheric Chemist Solomon’s work helped confirm that chlorine-containing compounds deplete ozone, and explained why this depletion was focused over the Earth’s poles. Paula Hammond – Chemical Engineer Hammond’s research focuses on nanoscale polymers for drug delivery and other applications. She co-founded the MIT Institute for Soldier Nanotechnology. Darleane Hoffman – Nuclear Chemist Hoffman was one of the researchers who confirmed the existence of element 106, Seaborgium. She also captured and analysed elements heavier than uranium. Carol Robinson – Physical Chemist The first female chemistry professor at both Cambridge and Oxford University. Uses mass spectrometry to reveal the structure and reactivity of proteins. Pratibha Gai – Materials Chemist Gai co-invented a type of microscope that allows visualisation of reactions at the atomic scale. She chose not to patent it so it could be easily used by others. Jacqueline Barton – Biophysical Chemist Barton studies the chemical and physical properties of DNA and the role of charge transport chemistry in DNA repain. She has received numerous awards for her work. Jennifer Doudna – Molecular Biochemist Doudna was a leading figure in the development of CRISPR gene editing, a technology that could in the future lead to treatments for a range of diseases. Tu Youyou – Pharmaceutical Chemist Won a Nobel Prize for her discovery of artemisinin, a compound derived from the wormwood plant and used as a drug to treat malaria. Lesley Yellowlees – Inorganic Chemist The first female president of the Royal Society of Chemistry. Her research focuses on electron transfer reactions, solar energy and EPR spectroscopy. Polly Arnold – Organometallic Chemist Arnold’s research focuses on synthetic chemistry and theories of bonding and reactivity, with the ai, of understanding the behaviour of nuclear waste.
Figure 2a “Twelve Women in Chemistry” by Andy Brunning/Compound Interest is licensed under CC BY-NC-ND 4.0.

Attribution & References

Except where otherwise noted, this page is adapted by JR van Haarlem from “1.4 Measurements”, In Chemistry 2e (Open Stax) by Paul Flowers, Klaus Theopold, Richard Langley & William R. Robinson is licensed under CC BY 4.0. ​Access for free at Chemistry 2e (OpenStax)​ / One paragraph is used from the source page as an introduction to this section.

License

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Chemistry v. 1 backup Copyright © 2023 by Gregory Anderson; Caryn Fahey; Jackie MacDonald; Adrienne Richards; Samantha Sullivan Sauer; J.R. van Haarlem; and David Wegman is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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