An Introduction to Chemistry for Engineers

Definition and Significance of Chemistry

Chemistry is a branch of science that investigates matter, specifically focusing on its state, composition, properties, and the changes it undergoes, including energy variations and governing laws. It is essential for advancements in materials technology, drug development, and food production. Within this field, environmental chemistry seeks to address environmental ills like air and water pollution. Historical contexts, such as the extinction of dinosaurs $65\,\text{million years}$ ago noted by Luis W. Alvarez of University of California, illustrate the importance of understanding natural world transformations throughout history.

Environmental Impact and the Scientific Method

Environmental research indicates Earth's temperature has risen about $1\,\text{degree Fahrenheit}$ over the last century, contributing to sea level increases of $4$ to $8\,\text{inches}$. Excessive greenhouse gas emissions from burning coal, natural gas, and oil are major contributors, with the United States producing $20\,\text{percent}$ of global emissions in $1997$. To study such phenomena, scientists employ the scientific method—a systematic pursuit of knowledge involving problem formulation, data collection through observation and experiment, and the formulation and testing of hypotheses. A hypothesis that is consistent with observations and predictions becomes a theory.

Branches of Chemistry

Chemistry is categorized into five primary branches. Organic chemistry focuses on the study of carbon-containing compounds, with the exception of $CO$, $CO_2$, $CO_3$, and $CN$, while Inorganic chemistry deals with compounds generally lacking hydrocarbon radicals. Analytic chemistry is concerned with the qualitative and quantitative identification of substances to determine what and how much is present. Physical chemistry examines the physical properties of substances and the energy changes involved in bond formation. Biochemistry is dedicated to the chemistry of living things.

Historical Development and Milestones

The field evolved through several eras, from prehistoric times and alchemy to modern science. Early records from King Hammurabi in $1700\,\text{BC}$ listed metals, with gold being the first metal used by man. Democritus of Ancient Greece ($430\,\text{BC}$) proclaimed the atom as the simplest unit of matter, whereas Aristotle ($300\,\text{BC}$) proposed a four-element theory consisting of fire, air, water, and earth. Alchemy flourished from $300\,\text{BC}$ until the late $17^{\text{th}}\text{ century}$, characterized by failed attempts to discover the Philosopher’s Stone for metal transmutation and an Elixir of Life. The publication of The Skeptical Chemist by Robert Boyle eventually led to the decline of alchemy.

Evolution into Modern Chemistry

Modern chemistry began to take shape between the end of the $17^{\text{th}}$ and mid-$19^{\text{th}}$ centuries. The Phlogiston Theory, supported by Johann J. Beecher and George Ernst Stahl, was eventually disproved by Antoine Lavoisier, who is known as the "Father of Modern Chemistry." Lavoisier correctly identified oxygen, which had been explored earlier by Carl Scheele and Joseph Priestly. Physical foundations were established through Coulomb’s Law by Charles Coulomb and the Atomic Theory published by John Dalton in $1803$. Scientific progress continued with the discovery of subatomic particles: Eugene Goldstein discovered the proton in $1885$, JJ Thomson identified the electron in $1897$, and James Chadwick discovered the neutron in $1932$.