Don’t Monkey Around – What is a Banana Bond?

Chemistry, Education
A banana bond is not a typical chemical bond by any stretch of the imagination. It is a 3-center, 2-electron bond. The shape of this kind of bond resembles a banana, hence its name. Perhaps the simplest example of a banana bond is demonstrated between boron and hydrogen in the diborane molecule, B2H6. Elemental Atomic Orbitals We begin with a discussion of the much simpler, more typical 2-center, 2-electron single bond. When atoms form molecules, the atomic orbitals involved transform into molecular orbitals. Let's consider a very simple example. Say we want to form one C-H bond of the molecule methane (CH4). Now hydrogen atoms only have one electron. The single electron lies in the 1s2 orbital. That type of orbital possesses spherical symmetry. Unlike hydrogen, carbon has 12 electrons…
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Why Some Sugars Have a Cyclic and a Chain Structure

Chemistry, Education
In your current course of organic chemistry, you're studying sugars. You notice in a text or see on the web a particular sugar, you've searched for by name. What is its true structure? You see it drawn as a chain structure with pendant groups. As you read about it, you see reference to another structure... a cyclic structure! What gives? Sugars: Example Fructose Some chemicals undergo change with the most minimal modification of environment. One example is keto-enol tautomerism. Fructose and certain other sugars experience something similar. It reacts reversibly, to form two cyclic hemiketals. Fructose Hemiketals A hemiketal forms by combination of an alcohol group with a ketone group. Fructose supplies both reactive groups, internally. For the generic reaction for hemiketal formation, see the accompanying illustration. Note the presence…
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Earth Gravity – Distinguishing the Forest and Trees

Education, Physics
There's no point attempting to explain the precise nature of gravity here. Most of us are aware it is Earth gravity that enables us to remain standing on the planet. Gravitational force operates on all matter.¹ Is Matter the Same as Weight? No, the two are not the same. To illustrate, say a man is seated at the doctor's office and he is invited back. He is requested to stand on a scale. It says he weighs 210 lbs. We write w = 210 lbs. Now say that man is an astronaut. Ah! Next week he is deep in space. If he removes his restraints, he begins to float. He is weightless!² That is, w = 0 lbs. Yet his mass remains the same. That is, m ≠ 0. Weight…
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Static Friction and Kinetic Friction AKA Sliding Friction

Education, Physics
You return home. You find that while you were gone, the UPS man dropped off a large cardboard box in front of your garage. The box is made of very thick cardboard. Clouds are rolling in. You need to put the box in the garage. But it's just you and the box is super-heavy. You have no alternative but to push it in. You Take Note You've had your coffee today, so you're on top of your game. Your mind is sharp as it will ever get. You position your hands and shove the box with everything you've got. You give it your best! Curiously once it starts, it isn't that hard to move, as long as you keep moving. You realize with that Sherlock Holmes brain of your that…
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A Simple Valence Problem for a Beginning Chemistry Enthusiast

Chemistry, Education
It is not unusual for school systems to introduce students to chemistry by means of the Periodic Table of the Elements. The table is then broken down into sections: the metals, the non-metals, and the gases. Before long, the structure of the atom is discussed, including protons, neutrons, electrons, orbitals, shells, and valence. It is the last of these we will briefly discuss here – valence. First a very brief discussion, followed by examples, followed by a puzzling problem (to impart insight). Valence: A Simple Discussion Atoms, although containing positive protons and negative electrons, have a net charge of zero. They are electrically neutral. This means each lone atom has a number of electrons equal to its number of protons. For instance, a sodium atom¹ has 11 protons. It also…
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Chemistry Students: Remember the Water of Crystallization

Chemistry, Education
[caption id="attachment_24966" align="alignright" width="480"] Don't forget the water.[/caption] Chemicals are, for the most part, categorized into inorganic compounds and organic compounds. The expression "water of crystallization" is rarely applied to organic compounds, since most of them are not water soluble, and if they are, few even of those form crystals with water. What IS Water of Crystallization? A high percentage of water-soluble inorganic salts form crystals that include water in their crystal lattice. An example of a salt, with and without water of crystallization is cupric sulfate.¹ Such salts, deprived of water content, are termed anhydrous. In our example, we might speak of copper sulfate anhydrous.² Quantity of Water [caption id="attachment_24967" align="alignright" width="380"] Fine crystals of copper sulfate pentahydrate.[/caption] Hydrated copper sulfate includes 5 molecules of water in its crystalline…
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Chemical Indicators for Advanced Homeschool From Flowers and Spices

Chemistry, Education
[caption id="attachment_24335" align="alignright" width="480"] Tautomers of curcumin found in turmeric.[/caption] "And the leaves of the trees were for the healing of the nations.” -Revelation 22:2c While the above quote is not intended as a discussion of home remedies, people have converted roots, leaves, flowers, and stems to teas, emoluments, and powders for the purpose of healing for many, many years. Of greater interest to us, you can use flowers and spices in much the same way a chemist uses commercial indicators in chemical titrations in the laboratory. A titration is the measured addition of a solution of known concentration into an another solution of unknown concentration with which it reacts, with the goal of reaching a proper end-point. And how does one know when the end-point has been reached? By…
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Bricks and Rocket Stoves Made From Clay, Dung and Straw

Education, People
[caption id="attachment_24263" align="alignright" width="480"] This is a six-brick "rocket" stove before being plastered with clay. Image USAID[/caption] In relatively prosperous lands, buildings are constructed of such materials as concrete, steel, and wood. In many lands, however, such materials are out of reach. Less expensive materials must be used, especially for housing. Brick masonry is a logical choice. In the arts, dung may be added to clay without the straw in the manufacture of pottery. What’s the chemical background of this technique? Bricks: Early Origins Baked bricks were used even in early Bible accounts. Genesis 11:3 quotes individuals crossing the valley plain of Shinar: “And they began to say, each one to the other: “Come on! Let us make bricks and bake them with a burning process.” So brick served as…
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Introduction to Chemistry Subscripts and Superscripts

Chemistry, Education
Subscript and superscript can make all the difference when it comes to chemical formulas. Molecules, compounds, and other chemical structures include more than one atom. Sometimes, there are multiples of one particular atom. For instance, anhydrous aluminum chloride features one atom of aluminum joined to or combined with three atoms of chlorine. Its chemical formula reflects this: AlCl₃. But – simply knowing how to use a number in this instance is not enough. It is essential to know the proper use of subscripts and superscripts. Subscripts in Chemistry Notice the number 3 is written as a subscript, or a number that is smaller than the other text, and below the normal text line, in the formula for anhydrous aluminum chloride above. The concept of a multiplicity of atoms is conveyed…
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Where Does Crude Oil Come From? Biotic or Abiotic Processes?

Chemistry, Education
Crude oil is used in the production of gasoline, diesel fuel, and other important substances, including plastics. The crude oil comes from the ground beneath our feet. But the question arises, how did it get there? Where Does Crude Oil Come From? There are two basic theories for the origin of crude oil: biotic and abiotic. The biotic theory predominates. It attributes oil’s formation to the decay of animal and plant matter. The less widely accepted – even controversial – abiotic theory denies the involvement of living organisms in the production of crude oil. These two theories are finding most of their adherents in two camps – the Western camp (biotic) and the Russian-Ukrainian camp (abiotic) – although there are western scientists in the R-U camp. This division is especially…
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