Oxygen in earth’s crust

Oxygen makes up more than 45.5 percent of Earth s crust and 65 percent of the human body. It also constitutes 20 percent of Earth s gaseous atmosphere. Explain the difference between the oxygen in the atmosphere and the oxygen in Earth s crust and the human body. 

Silicon is the second most abundant element, after oxygen, in Earth s crust. It occvus in Si02 and in an enormous variety of silicate minerals. The element is obtained by the reduction of molten silicon dioxide with carbon at high temperature ... 

Figure 1.2.9. Comparison of the top forty eiements in Earth s crust with the top ten eiements in the body. The elements found in the body are numbered to show their abundance. Oxygen is the most abundant (1), carbon is second (2), etc.

The abundance of aluminum in Earth s crust is estimated to be about 8.8 percent. It occurs in many different minerals. Bauxite, a complicated mixture of compounds consisting of aluminum, oxygen, and other elements, is the primary commercial source for aluminum. 

Argon is the third most abundant gas in Earth s atmosphere, following nitrogen and oxygen. Its abundance is about 0.93 percent. It is also found in Earth s crust to the extent of about 4 parts per million. 

Hydrogen occurs on Earth primarily in the form of water. Every molecule of water (H2O) contains two hydrogen atoms and one oxygen atom. Hydrogen is also found in many rocks and minerals. Its abundance is estimated to be about 1,500 parts per million. That makes hydrogen the 10th most abundant element in Earth s crust. 

Nitric oxide is more active than free nitrogen. For example, nitric oxide combines with oxygen and water in the atmosphere to make nitric acid. When it rains, nitric acid is carried to the earth. There it combines with metals in Earth s crust. Compounds known as nitrates and nitrites are formed. 

Oxygen is by far the most abundant element in Earth s crust. Nearly half of all the atoms in the earth are oxygen atoms. Oxygen also makes up about one-fifth of Earth s atmosphere. Nearly 90 percent of the weight of the oceans is due to oxygen. In addition, oxygen is thought to be the third most abundant element in the universe and in the solar system. 

Silicon is the second most abundant element in Earth s crust, exceeded only by oxygen. Many rocks and minerals contain silicon. Examples include sand, quartz, clays, flint, amethyst, opal, mica, feldspar, garnet, tourmaline, asbestos, talc, zircon, emerald, and aquamarine. Silicon never occurs as a free element. It is always combined with one or more other elements as a compound. 

Silicon is the second most abundant element in Earth s crust. Its abundance is estimated to be about 27.6 percent of the crust. It ranks second only to oxygen. Some authorities believe that more than 97 percent of the crust is made of rocks that contain compounds of silicon and oxygen. 

Aluminum is the third most abundant element in Earth s crust, exceeded only by oxygen and silicon. It is second to silicon as the most abundant metallic element. It is somewhat surprising, then, that aluminum was not discovered until relatively late in human history. Aluminum occurs naturally only in compounds, never as a pure metal. Removing aluminum from its compounds is quite difficult. An inexpensive method for producing pure aluminum was not developed until 1886. 

The most abundant elements in Earth s crust, silicon and oxygen, are usually found in silica, which can be melted and rapidly cooled to form glass. 

As you can see from the graph, oxygen makes up about 46 percent of Earth s crust. Nearly all of this oxygen occurs in compounds with other elements. Silicon is the next most abundant element in Earth s crust. Therefore, you won t be surprised to learn that much of the oxygen is tied up in silicon dioxide, commonly known as sand. 

The thin outer layer of Earth, called the crust, contains only 0.50% of Earth s total mass and yet is the source of almost all the elements (the atmosphere provides elements such as oxygen, nitrogen, and a few other gases). Silicon (Si) is the second most abundant element in Earth s crust (27.2% by mass). Calculate the mass of silicon in kilograms in Earth s crust. (The mass of Earth is 5.9 X 10 tons. 1 ton = 2000 lb 1 lb = 453.6 g.)... 

Elemental oxygen, O2, is paramagnetic and contains two unpaired electrons. Oxygen forms ozone (O3), oxides (O ), peroxides (O2 ), and superoxides (O2). The most abundant element in Earth s crust, oxygen is essential for life on Earth. 

Infer The alkaline earth metals are usually found combined with oxygen and other nonmetals in Earth s crust. Based on the atomic properties of this group, explain why alkaline earth metals are so reactive. 

Oxygen is element number 8 and the most abundant element in Earth s crust. The pure element exists in two allotropic forms and O3 (ozone), which are both gaseous species under average atmospheric conditions. Diatomic oxygen gas, O, composes 21 percent of the atmosphere and is an essential biological element. Ozone composes a thin layer of the stratosphere and is essential to protecting life on the surface of Earth from otherwise harmful ultraviolet radiation. Unfortunately, in the troposphere, ozone is an air pollutant. 

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