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  2. Abundance of the chemical elements - Wikipedia

    en.wikipedia.org/wiki/Abundance_of_the_chemical...

    The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.

  3. Marine biogeochemical cycles - Wikipedia

    en.wikipedia.org/wiki/Marine_biogeochemical_cycles

    Silicon is a bioessential element and is one of the most abundant elements on Earth. [61] [62] The silica cycle has significant overlap with the carbon cycle (see the carbonate–silicate cycle) and plays an important role in the sequestration of carbon through continental weathering, biogenic export and burial as oozes on geologic timescales. [63]

  4. Marine chemistry - Wikipedia

    en.wikipedia.org/wiki/Marine_chemistry

    Marine chemistry, also known as ocean chemistry or chemical oceanography, is the study of the chemical composition and processes of the world’s oceans, including the interactions between seawater, the atmosphere, the seafloor, and marine organisms. [2]

  5. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    Oxygen is the third most abundant chemical element in the universe, after hydrogen and helium. [68] About 0.9% of the Sun's mass is oxygen. [19] Oxygen constitutes 49.2% of the Earth's crust by mass [69] as part of oxide compounds such as silicon dioxide and is the most abundant element by mass in the Earth's crust.

  6. Geological history of oxygen - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_oxygen

    Although oxygen is the most abundant element in Earth's crust, due to its high reactivity it mostly exists in compound forms such as water, carbon dioxide, iron oxides and silicates. Before photosynthesis evolved, Earth's atmosphere had no free diatomic elemental oxygen (O 2). [2]

  7. 108 “Are You Smarter Than A 5th Grader?” Questions For Your ...

    www.aol.com/lifestyle/108-smarter-5th-grader...

    What is the main gas found in the Earth’s atmosphere? Answer: Nitrogen ... What is the most abundant element in the universe? Answer: Hydrogen ... One of our most popular items of 2024, AOL ...

  8. Great Oxidation Event - Wikipedia

    en.wikipedia.org/wiki/Great_Oxidation_Event

    An atmosphere of N 2 and CO 2 with trace amounts of H 2 O, CH 4, carbon monoxide (CO), and hydrogen (H 2) is described as a weakly reducing atmosphere. [16] Such an atmosphere contains practically no oxygen. The modern atmosphere contains abundant oxygen (nearly 21%), making it an oxidizing atmosphere. [17]

  9. The Most Abundant Chemical in the Universe Could Become ... - AOL

    www.aol.com/most-abundant-chemical-universe...

    Hydrogen is the most abundant element to the universe—it's actually element number one—and the atomic weight is 1.008, so 10/08 is designated National Hydrogen and Fuel Cell day, because many ...