KEY IDEA: Chemistry is the scientific study of matter and energy, and the changes they undergo.
Introduction to chemistry
Chemistry: the study of matter and energy, and the changes they undergo.
Matter: anything with mass and volume; the physical "stuff" of the universe.
Energy: the ability to do work.
- Chemists study the composition, structure, and properties of matter.
Matter: anything with mass and volume; the physical "stuff" of the universe.
Energy: the ability to do work.
- Several different forms (electrical, thermal (or heat), radiant (like light), etc..
- Matter can be converted into energy.
- Einstein's Theory of Relativity, E=mc^2
Chemistry is also defined by the scale at which the subject is studied. Chemists (generally) study atoms, the infinitesimally small "building blocks" of matter.
Fundamental forces governing the behavior of atoms and molecules at this minute level have a significant effect on the bulk of everyday objects. |
Every THING is made of matter; therefore, chemistry affects ALL aspects of life and most natural events.
Branches of Chemistry
Traditionally FIVE (5) main areas:
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Pure vs. Applied science
Sometimes there is no clear line between pure and applied research.
- Pure science – the pursuit of knowledge for its own sake.
- Generally, has no practical use or application.
- Pure research may lead directly to an application. (e.g., nylon)
- Applied science – research directed towards a practical goal or application.
- However, an application may exist before research is done to explain how it works. (e.g., aspirin)
Sometimes there is no clear line between pure and applied research.
Chemistry attempts to explain the observable universe in terms of the interactions of infinitesimal particles.
Alchemy
Chemistry has its origins in the medieval (3500 BC) practice of alchemy.
- Ancient philosophy and theory of matter:
- Aimed to explain the nature of all matter in terms of fundamental "building blocks"
- 4 "elements," Earth, Water, Air, Fire, exhibiting 2 of 4 properties: hot, cold, dry, wet
- Attempted to transform (trans-mutate) matter by altering the basic properties
- Arose independently around the world (Arabs to Spain to Europe; Chinese)
- Developed tools and techniques for working with chemicals, dyes, glass
- Beakers, tongs, funnels, mortar & pestle; separate mixtures, purification
- Studies were limited to only observations, thus failed to provide logical explanations for changes in matter
- Attempts to transform common base metals (mercury, lead) into "perfect" metal (gold);
- Futile search of a magical, mythical potion granting eternal life ("philosopher's stone")
- Attempts to transform common base metals (mercury, lead) into "perfect" metal (gold);
- Element (redefined 17th century): any material that cannot be broken down into a simpler substance
Chemical revolution
By the 17th century, a changed attitude characterized by a reliance on experimentation had been adopted by astronomers, physicists, physiologists, and signaled the emergence of chemistry from alchemy.
Traditionally regarded as the "Father of Modern Chemistry," Frenchman Antoine Lavoisier revolutionized chemistry, transforming it from a science of observation into a science of measurement. His wife, Marie-Anne, served as his indispensable lab assistant.
Lavoisier's research is among the earliest quantitative chemical experiments. Carefully weighing reactants and products, he showed that although matter may change its form, the total mass remains unchanged, thus concluding "The Law of Conservation of Mass." |
It is hard to overstate Lavoisier's contribution to science. In 15 years, he discovered air is a mixture; isolated and named elements hydrogen and oxygen; predicted the existence of silicon; made the first extensive list of the elements; helped develop the metric system; and reformed chemical nomenclature.
His wife, Marie-Anne Paulze, was an indispensable laboratory assistant and was an important contribution to his work.
The Scientific Method
The scientific method is idealized as a logical and systematic cycle of inquiry to solve a problem.
The first step in most scientific studies is the collection of data:
1. Observation – obtain information, research, measurement, or experimentation
Observation often leads to a question.
2. Hypothesis – an “educated guess”
3. Develop Theory – a well-supported hypothesis
Experiment – a controlled procedure designed to test a hypothesis.
Control – a standard for comparison; a reference
Variables – “things” that get affected in an experiment:
If you keep other factors that can affect the experiment from changing during the experiment, you can relate any change in the responding variable to changes in the manipulated variable. Minimizing the number of independent variables is a constant challenge of experimental design.
The first step in most scientific studies is the collection of data:
1. Observation – obtain information, research, measurement, or experimentation
- Quantitative – relating to measurement; involves a quantity (number)
- Qualitative – non-mathematical; based on quality
Observation often leads to a question.
2. Hypothesis – an “educated guess”
- a proposed explanation for an observation
- attempts to answer the question
- must be testable by experimentation
- may be revised based on experimental data
3. Develop Theory – a well-supported hypothesis
Experiment – a controlled procedure designed to test a hypothesis.
Control – a standard for comparison; a reference
- responds predictably - we know the results
Variables – “things” that get affected in an experiment:
- Independent (or manipulated) variable
- the “thing” that gets changed during an experiment
- Dependent (or responding) variable
- the “thing” that is observed during an experiment
If you keep other factors that can affect the experiment from changing during the experiment, you can relate any change in the responding variable to changes in the manipulated variable. Minimizing the number of independent variables is a constant challenge of experimental design.
Theory– attempt to explain WHY something happens;
Examples: Big Bang Theory, Atomic Theory, Theory of Relativity, Quantum Theory, Kinetic-Molecular Theory, etc.
Law– attempts to tell WHAT happens
Examples: Newton's Laws of Motion, Law of Conservation of Matter, Laws of Thermodynamics, Ideal Gas Law, etc.
- A well-tested explanation for a set of observations.
- Cannot be proven right; only disproved
Examples: Big Bang Theory, Atomic Theory, Theory of Relativity, Quantum Theory, Kinetic-Molecular Theory, etc.
Law– attempts to tell WHAT happens
- Summarizes natural phenomenon
- Predicts the future
Examples: Newton's Laws of Motion, Law of Conservation of Matter, Laws of Thermodynamics, Ideal Gas Law, etc.
The scientific method is rarely followed as an exact cycle. Human imagination, intuition, and chance are vital elements of the process.
Explore Further
From IMDB: - Graham Young (Hugh O'Conor) is a teenage misfit living in suburban London in the 1960s. He hates his stepmother (Ruth Sheen) but loves chemistry, and the two impulses unite in a wicked plot to slowly poison her. After she dies, he's found guilty and sent to a psychiatric hospital, where an idealistic doctor (Antony Sher) thinks he can be cured. Upon release, Graham finds a job, but struggles to fight back his old urges for murder. The film is based on the true story of the "Teacup Murderer."
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