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Chemistry LibreTexts

1: Introduction

  • Page ID
    • 1.1: Hypothesis, Theories, and Laws
      Although all of us have taken science classes throughout the course of our study, many people have incorrect or misleading ideas about some of the most important and basic principles in science. We have all heard of hypotheses, theories, and laws, but what do they really mean? Before you read this section, think about what you have learned about these terms before. What do these terms mean to you? What do you read contradicts what you thought? What do you read supports what you thought?
    • 1.2: The Scientific Method - How Chemists Think
      Science is a process of knowing about the natural universe through observation and experiment. Scientists go through a rigorous process to determine new knowledge about the universe; this process is generally referred to as the scientific method. Science is broken down into various fields, of which chemistry is one. Science, including chemistry, is both qualitative and quantitative.
    • 1.3: Radiation and the Wave Nature of Light
      Light and other forms of electromagnetic radiation move through a vacuum with a constant speed, c. This radiation shows wavelike behavior, which can be characterized by a frequency, ν, and a wavelength, λ, such that c = λν. Light is an example of a travelling wave. Other important wave phenomena include standing waves, periodic oscillations, and vibrations. Standing waves exhibit quantization, since their wavelengths are limited to discrete integer multiples of some characteristic lengths.
    • 1.4: The failures of Classical Mechanics- the Particle Nature of Light
      Classical mechanics is unable to explain certain phenomena observed in nature including the emission of blackbody radiators that is sensitive to the temperature of the radiator, the photoelectric effect and the discrete emission  obtained from atoms.  These effects are readily explained if the radiation is considered  to be quantized (particle perspective)
    • 1.5: Early Experiments to Characterize the Atom
      Here is a short description of early experiments providing fundamental data to understand the atom.  Their interpretation was done under Classical Mechanics, thus they provide a fundamental but  incomplete picture of the properties of atoms.
    • 1.6: First attempts to model the H atom
      Initial attempts to understand and model the H-atom provided an explanation of the atomic line-spectra but left many questions unanswered.
    • 1.7: Matter as Waves
      While the photoelectron effect demonstrated that light can be wave-like and particle-like (e.g., "photon"), de Broglie demonstrated that matter also exhibits wave-like and particle-like behavior.  The connection between de Broglie wavelength and standing waves helped the understanding of Bohr's atom model.

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