Elemental Composition of Pure Substances

3 Key excerpts on "Elemental Composition of Pure Substances"

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  Chemistry: Atoms First

  • William R. Robinson, Edward J. Neth, Paul Flowers, Klaus Theopold, Richard Langley(Authors)
  • 2016(Publication Date)
  • Openstax

    (Publisher)

  Each compound has a specific composition and possesses definite chemical and physical properties by which we can distinguish it from all other compounds. And, of course, there are innumerable ways to combine elements and compounds to form different mixtures. A summary of how to distinguish between the various major classifications of matter is shown in (Figure 1.14). Figure 1.14 Depending on its properties, a given substance can be classified as a homogeneous mixture, a heterogeneous mixture, a compound, or an element. Eleven elements make up about 99% of the earth’s crust and atmosphere (Table 1.1). Oxygen constitutes nearly one- half and silicon about one-quarter of the total quantity of these elements. A majority of elements on earth are found in chemical combinations with other elements; about one-quarter of the elements are also found in the free state. Elemental Composition of Earth Element Symbol Percent Mass Element Symbol Percent Mass oxygen O 49.20 chlorine Cl 0.19 silicon Si 25.67 phosphorus P 0.11 aluminum Al 7.50 manganese Mn 0.09 Table 1.1 Chapter 1 | Essential Ideas 21 Elemental Composition of Earth Element Symbol Percent Mass Element Symbol Percent Mass iron Fe 4.71 carbon C 0.08 calcium Ca 3.39 sulfur S 0.06 sodium Na 2.63 barium Ba 0.04 potassium K 2.40 nitrogen N 0.03 magnesium Mg 1.93 fluorine F 0.03 hydrogen H 0.87 strontium Sr 0.02 titanium Ti 0.58 all others - 0.47 Table 1.1 Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15). Chemistry in Everyday Life 22 Chapter 1 | Essential Ideas This OpenStax book is available for free at http://cnx.org/content/col12012/1.7 Figure 1.15 The decomposition of water is shown at the macroscopic, microscopic, and symbolic levels.

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  Chemistry

  • Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson(Authors)
  • 2015(Publication Date)
  • Openstax

    (Publisher)

  Each compound has a specific composition and possesses definite chemical and physical properties by which we can distinguish it from all other compounds. And, of course, there are innumerable ways to combine elements and compounds to form different mixtures. A summary of how to distinguish between the various major classifications of matter is shown in (Figure 1.14). Figure 1.14 Depending on its properties, a given substance can be classified as a homogeneous mixture, a heterogeneous mixture, a compound, or an element. Eleven elements make up about 99% of the earth’s crust and atmosphere (Table 1.1). Oxygen constitutes nearly one- half and silicon about one-quarter of the total quantity of these elements. A majority of elements on earth are found in chemical combinations with other elements; about one-quarter of the elements are also found in the free state. Elemental Composition of Earth Element Symbol Percent Mass Element Symbol Percent Mass oxygen O 49.20 chlorine Cl 0.19 silicon Si 25.67 phosphorus P 0.11 aluminum Al 7.50 manganese Mn 0.09 Table 1.1 Chapter 1 | Essential Ideas 21 Elemental Composition of Earth Element Symbol Percent Mass Element Symbol Percent Mass iron Fe 4.71 carbon C 0.08 calcium Ca 3.39 sulfur S 0.06 sodium Na 2.63 barium Ba 0.04 potassium K 2.40 nitrogen N 0.03 magnesium Mg 1.93 fluorine F 0.03 hydrogen H 0.87 strontium Sr 0.02 titanium Ti 0.58 all others - 0.47 Table 1.1 Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15). Chemistry in Everyday Life 22 Chapter 1 | Essential Ideas This OpenStax book is available for free at http://cnx.org/content/col11760/1.9 Figure 1.15 The decomposition of water is shown at the macroscopic, microscopic, and symbolic levels.

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  Janice VanCleave's Big Book of Science Experiments

  • Janice VanCleave(Author)
  • 2020(Publication Date)
  • Jossey-Bass

    (Publisher)

  Part I 1 CHEMISTRY C hemistry is the study of matter, its physical and chemical properties, and how it changes. This science involves all of one’s senses: seeing, hearing, tasting, feeling, and smelling. It is listed first in this book because chemistry concepts are a springboard into the other sciences. You cannot understand the physics concept of electricity without understanding the chemistry of atoms, or the formation of crystals in caves in earth science, or biochemical reactions in the fruit ripening process in biology without understanding chemical reactions. Chemistry is not restricted to scientists working in laboratories; instead, knowledge of chemistry is important in our everyday lives. Who knows? You might be on some reality show or confronted with an unexpected survival situation. You would be cut off from electrical devices. Chemistry knowledge would help you use available resources. Yes, your brain is your best survival tool in emergencies; but it is also the best problem-solving tool you have. Chemistry is all about problem solving, and the investigations in this book contain the foundation on which to build and sharpen your chemistry knowledge. 2 Matter Matter is anything that occupies space and has mass (an amount of matter making up a material). Matter is the stuff that makes up the Universe. Figure 1 shows a flow chart for the different types of matter. The term pure substance refers to one kind of matter, such as an element or a compound; without the adjective “pure,” the term substance is commonly used to refer to any material pure or not, and that is how it is used in this book. Mixture is a term that refers to the combination of different substances. Elements At this time, 118 different elements have been identified. The 94 elements that occur in nature are called natural elements, examples being carbon, oxygen, nitrogen, and sulfur. Synthetic elements are the 24 elements made by scientists in a laboratory.

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