The Chemistry of Everyday Elements 9781422238370, 9781422238394, 9781422279441, 1422238377

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THE CHEMISTRY OF EVERYDAY ELEMENTS

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Carbon

Mason Crest

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THE CHEMISTRY OF EVERYDAY ELEMENTS Aluminum Carbon Gold Helium Hydrogen Oxygen Silicon Silver Understanding the Periodic Table Uranium

THE CHEMISTRY OF EVERYDAY ELEMENTS

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Carbon By Jane P. Gardner

Mason Crest 450 Parkway Drive, Suite D Broomall, PA 19008 www.masoncrest.com © 2018 by Mason Crest, an imprint of National Highlights, Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, taping, or any information storage and retrieval system, without permission from the publisher. Printed and bound in the United States of America. Series ISBN: 978-1-4222-3837-0 Hardback ISBN: 978-1-4222-3839-4 EBook ISBN: 978-1-4222-7944-1 First printing 135798642 Produced by Shoreline Publishing Group LLC Santa Barbara, California Editorial Director: James Buckley Jr. Designer: Patty Kelley www.shorelinepublishing.com Library of Congress Cataloging-in-Publication Data on file with the Publisher. Cover photos: Dreamstime.com: Mopic (bkgd); Jzhender1 (factory); Dustin Kostic (vest); Richard Thomas (diamond)

QR Codes disclaimer: You may gain access to certain third party content (“Third-Party Sites”) by scanning and using the QR Codes that appear in this publication (the “QR Codes”). We do not operate or control in any respect any information, products, or services on such Third-Party Sites linked to by us via the QR Codes included in this publication, and we assume no responsibility for any materials you may access using the QR Codes. Your use of the QR Codes may be subject to terms, limitations, or restrictions set forth in the applicable terms of use or otherwise established by the owners of the Third-Party Sites. Our linking to such Third-Party Sites via the QR Codes does not imply an endorsement or sponsorship of such Third-Party Sites, or the information, products, or services offered on or through the Third-Party Sites, nor does it imply an endorsement or sponsorship of this publication by the owners of such Third-Party Sites.

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Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Discovery and History . . . . . . . . . . . . . . . . . . . 10 Chemical Properties . . . . . . . . . . . . . . . . . . . . . 22 Carbon and You. . . . . . . . . . . . . . . . . . . . . . . . . . 32 Carbon Combines. . . . . . . . . . . . . . . . . . . . . . . . 36 Carbon in Our World. . . . . . . . . . . . . . . . . . . . . 44 Find Out More. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Series Glossary of Key Terms. . . . . . . . . . . . . . . . . . . . . . . 63 Index/Author. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

KEY ICONS TO LOOK FOR

Words to Understand: These words with their easy-to-understand definitions will increase the reader’s understanding of the text, while building vocabulary skills. Sidebars: This boxed material within the main text allows readers to build k­ nowledge, gain insights, explore possibilities, and broaden their perspectives by weaving together additional information to provide realistic and holistic p­ erspectives. Educational Videos: Readers can view videos by scanning our QR codes, providing them with additional educational content to supplement the text. Examples include news cover­age, moments in history, speeches, iconic moments, and much more! Text-Dependent Questions: These questions send the reader back to the text for more careful attention to the evidence presented here. Research Projects: Readers are pointed toward areas of further inquiry connected to each chapter. Suggestions are provided for projects that encourage deeper research and analysis. Series Glossary of Key Terms: This back-of-the-book glossary contains terminology used throughout this series. Words found here increase the reader’s ability to read and comprehend higher-level books and articles in this field. 5

Carbon: INTRODUCTION

A Key Element

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ake a close look around you. What do you see? A book or perhaps a half-eaten piece of toast, sits on your desk. Outside your window, you might see clouds or rain or a bird flying by. As you look, your heart pumps your

blood throughout your body. All of those things that you see— including the eyes you use to see them—are the solids, liquids, and gases that are composed of elements of the periodic table. The periodic table is an arrangement of all the naturally occurring, and manufactured, elements known to humans at this point in time. There are 92 elements that can be found naturally on Earth and in space. The remaining 26 (or thereabouts) have been manufactured and analyzed in a laboratory setting. These elements, alone or in combination with others, form and shape all the matter around us. From the air we breathe, to the water we drink, to the food we eat—all these things are made of elements.

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The periodic table has undergone several updates and reorganizations since it was first developed in 1869, until the modern version of the table

This carbon diagram shows the six protons orbiting the atom’s nucleus.

used today. The periodic table is arranged by increasing atomic number, into rows and columns. Each element has a unique atomic number. It is the number of protons in the nucleus of the atom. For example, carbon has an atomic number of 6—there are six protons in the nucleus. All samples of an element have the same number of protons, but they may have a different number of neutrons in the nucleus. Atoms with the same number of protons but different number of neutrons are called isotopes. Each element on the periodic table is unique, having its own chemical and physical properties. But certain chemical properties can be interpreted based on which group or row an element resides in. The periodic table also gives information such as the number of protons and neutrons in the nucleus of one atom of an element, the number of electrons that surround the nucleus, the atomic mass, and the general size of the atom. It is also possible to The Chemistry of Everyday Elements

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predict which state of matter an element is most likely to be found— solid, liquid, or gas—based on its location. The periodic table is a very useful tool as one begins to investigate chemistry and science in general. This book is about the element carbon. Carbon, a nonmetal, has six protons and six neutrons in its nucleus. A stable atom of carbon has six electrons. Carbon is a solid under standard conditions. Just how useful is this element? We are carbon-based beings. All living things on Earth, from humans to blades of grass, from giant sequoias to tiny dust mites, are all carbon-based organisms. The cells of all living things are made of carbon. And carbon plays even more roles in our lives. The temperature on Earth is at a temperature that can sustain life thanks to the carbon in the atmosphere. Carbon, in a variety of forms, fuels our automobiles and buses, and in a lot of cases, warms our homes and helps cook our food. New technologies have opened up a whole new world of medicine and space exploration that utilizes the unique properties of carbon. We all use and need carbon in our lives, and we need to be mindful of how we use it and the lasting impact our use will have on future generations and on the health of the planet. 8

Periodic Table

The Periodic Table of the Elements is arranged in numerical order. The number of each element is determined by the number of protons in its nucleus. The horizontal rows are called periods. The number of the elements increases across a period, from left to right. The vertical columns are called groups. Groups of elements share similar characteristics. The colors, which can vary depending on the way the creators design their version of the chart, also create related collections of elements, such as noble gases, metals, or nonmetals, among others.

The Chemistry of Everyday Elements

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Carbon

WORDS TO UNDERSTAND

bronze metal made by melting together copper and another metal (usually tin)

geodesic dome a shape formed by interlocking 20-sided shapes that form a half-sphere

opaque so dark that light usually can’t pass through; opposite of transparent

Carbon: CHAPTER 1

Discovery and History

C

arbon is the sixth most abundant element in the entire universe. All the carbon that makes life on Earth possible formed in stars long ago. Chemical reactions in very young stars formed carbon and other elements.

As stars age, they use up the main ingredient of their cores (hydrogen), and collapse in on themselves. The stars eventually explodes in a supernova and the remaining carbon that is distributed through the universe. Here on Earth, it is virtually impossible to name any one person who discovered carbon. Carbon, in its many various forms, has been used by humans for millennia. According to the University of Kentucky’s Center for Applied Energy Research, the first known use of carbon was approximately 11

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Carbon

3750

bce

when ancient Egyptians and Sumerians used charcoal, a

form of pure carbon, to make bronze. Charcoal is formed when wood is burned and deprived of oxygen. What is left after this process is an impure form of carbon. Charcoal, especially in ancient times, was primarily used as a fuel, although today it has many alternative uses, including as a filtering device. The word carbon is thought to come from the Latin word for charcoal or coal: carbo. In French, the word is charbon, while in German it is kohle.

A Sumerian dagger made of bronze, which was created with the help of the carbon form called charcoal.

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Historical records and archeological finds indicate that carbon and carbon products were used for a variety of uses. Charcoal was used for medicinal purposes in 15,000 bce Egypt. Writings on ancient papyrus suggest that charcoal was used to treat wounds and prevent them from becoming infected. It was also used to support the health of the intestinal tract. Hippocrates, an ancient Greek physician, used charcoal to treat conditions such as epilepsy and anthrax. The Phoenicians used wooden barrels that had been charred on the inside to store their drinking water on the long trading voyages. This charring, which created a layer of carbon by burning the wood, kept the water from becoming contaminated and kept it tasting fresher. Other cultures, including Hindu in what is now India, were using charcoal along with sand to filter and purify their drinking water as far back as roughly 450 bce. Here Comes Oil For centuries, scientific knowledge continued to grow and develop. Much work was done to explore the different forms that carbon can take. In the 1770s, Antoine Lavoisier, a French chemist The Chemistry of Everyday Elements

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Diamonds vs. Graphite While both diamonds and graphite are made of carbon (and only carbon, with some minor impurities at times), they have very different properties. Graphite (below) has a hardness of about 2 on Mohs’ Hardness Scale, while diamond has a hardness of 10. Diamonds are insulators, while graphite can conduct electricity. Graphite is opaque, while diamonds, for the most part, are transparent. The reason behind these differences? It has to do with the arrangement and bonding of the carbon atoms on a very, very small scale—the nanoscale.

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who has been called the Father of Modern Chemistry, used a powerful lens to prove that diamonds, when they combust (or burn), give off carbon. He focused beams of sunlight on a diamond within an environment rich in oxygen. He found that the only product from this reaction was carbon dioxide. Seeing that, Lavoisier had proved that the only element making up diamond

French scientist Antoine Lavoisier made key finds in chemistry.

was carbon. A few years later, in 1797, Smithson Tennant, an English chemist who was best known for discovering the elements iridium and osmium, conducted the same experiment with one added step. He did the same thing with both diamond and graphite, proving that diamond and graphite are both composed of pure carbon. In the 1800s, the exploration, extraction, and use of carbon-based fossil fuels exploded worldwide. Prior to the 1800s, wells had been dug in Pennsylvania and West Virginia seeking salt for the citizens of the area. In 1815, such a well was drilled in West Virginia and one of The Chemistry of Everyday Elements

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the byproducts was natural gas. At the time, it was an unexpected, and largely undesirable, byproduct. However, people soon began to use the natural gas as a fuel to separate the salt from the briny water in the wells. By the 1880s, there were 16 other sites in Ohio, Pennsylvania, and West Virginia using natural gas from the wells to produce salt using this carbon-based fuel. Also in the mid-1800s, oil wells were drilled in Europe, Canada, and in the United States. The first US oil well was drilled in 1859 in Titusville, Pennsylvania. Natural gas and oil in the form of kerosene completely replaced whale oil by the end of the 1800s as a way of creating light. Carbon-based fuels were changing the way that peoA vintage postcard shows an early oil well in Pennsylvania.

ple powered machines, warmed their homes, and lit their lives.

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This diagram shows the physical makeup of the carbon form known as C60.

New Forms of Carbon Up until the 1980s, it was believed that carbon could take only two forms: that of a diamond or that of graphite. In 1985 a new form of carbon was discovered—C60. Scientists looking at how elements exist in space did some experiments on carbon found on Earth. By heating graphite to star-like temperatures, they found that another kind of carbon formed. The clusters of recrystallized carbon formed into pure carbon, but a form that was arranged in a different way, called C60. These molecules of carbon are shaped like a geodesic dome. It is also useful to think of them as shaped like a soccer ball. More commonly referred to as “buckyballs,” the discovery of this form of carbon, also known as buckminsterfullerene, was a surprise. The Chemistry of Everyday Elements

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At the moment, there are no commercial applications or uses for buckyballs. Some limited uses in medicine or in the manufacture of solar cells have been proposed but widespread use of them has not become common. Their significance lies in the fact that they were the first, of what turns out to be many, alternative forms of carbon to be discovered. After the discovery of Carbon molecules inspired the creation of the magnetic toys known as Buckyballs.

buckminsterfullerene, other carbon molecules were discovered. Grouped as fullerenes, these molecules can take on many shapes. They may be tubes, elliptical, or hollow spheres. Carbon nanotubes have many applications in of electronics and nanotechnology, as well as biotechnology and medicine. This in-

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Buckminster Fuller Scientists Robert Curl, Harold Kroto, and Richard Smalley were jointly awarded the 1996 Nobel Prize in Chemistry for their discovery of a form of carbon that was given the name buckminsterfullerene. They took the name from Buckminster Fuller, an American inventor, architect, and author. He is probably best known for his popular design of the geodesic dome. Geodesic domes have a network of icosahedrons, or 20-sided figures, arranged in a sphere. This is the same shape that buckyballs were found to have.

The Chemistry of Everyday Elements

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Carbon

This illustration shows the internal structure of a fullerene nanotube.

cludes MRI technology, X-ray imaging, the delivery of drugs or genes to specific sites within the body, and cancer research. For example, fullerenes have been produced that can be absorbed by unwanted cancerous cells. The fullerene molecules absorbed by the cancerous cells can react to radiation, minimizing the damage done to surround20

ing healthy cells. This is just one of many new applications scientists are working on. Carbon has had a long history, but its most amazing uses just might be in the future.

Text-Dependent Questions 1. Name an early use of carbon in ancient times. 2. Where was natural gas first used in the US? 3. What was the chemical name of the new form of carbon called the buckminsterfullerene? Research Project Read about the early days of oil exploration in America. Seeing what oil and gas have grown into, write a letter to one of those early oilmen warning him of the dangers of the road ahead!

The Chemistry of Everyday Elements

History of oil production

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WORDS TO UNDERSTAND

allotropes different forms that an element can take

Carbon: CHAPTER 2

Chemical Properties

C

arbon has an atomic number of 6 on the Periodic Table of Elements. It has six protons in its nucleus and six electrons in the cloud of electrons surrounding the nucleus.

The structure of carbon is unique, and it lends itself to

making many different types of compounds (see Chapter 3). A compound is when two or more elements or chemicals are mixed together to create a new product. As a result of all these possible combination options for carbon atoms, almost 10 million compounds of carbon have been discovered! It is estimated that for all the known compounds on the planet, carbon is a component in 95 percent of them. Carbon exists as a solid on, and in, Earth’s surface. It also is 23

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the main component of several different gases in Earth’s atmosphere. Earth’s crust and upper mantle contain only about 0.032 percent carbon. Some of that is mixed with oxygen to form carbon dioxide (CO2), which today makes up about just 0.04 percent of Earth’s atmosphere. However, this is actually an increase over the amount that was in the atmosphere when the planet formed. This is due to the release of carbon dioxide into the atmosphere through the burning of fossil Car exhaust contains carbon as part of the compound carbon dioxide.

fuels such as coal, natural gas, and petroleum products.

Carbon Dioxide in the Atmosphere The introduction of carbon into the atmosphere through the burning of fossil fuels has raised concerns about global warming and the greenhouse effect. Greenhouse gases also include water vapor, 24

Carbon dioxide is one of the chemicals in the air that traps heat in the atmosphere.

methane, and nitrous oxide. These gases trap heat in the atmosphere, warming the surface of Earth. Carbon dioxide and the other greenhouse gases allow some energy from the Sun to pass through Earth’s atmosphere. Some of that energy bounces back into space and some of it is absorbed by the gases in the atmosphere. Much of it, however, is trapped by the greenhouse gases, further warming Earth’s surface. The more greenhouse gases in the atmosphere, the more heat will become trapped close to the surface, ultimately raising global temperatures. This effect has grown greatly over the past century, since the introduction of carbon-based fossil fuels. Nearly all of the hottest years

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Carbon Monoxide Carbon monoxide is another molecule that forms when compounds that contain carbon are burned. This includes the burning of fuels, or other sources such as volcanic eruptions or forest fires. Carbon monoxide contains one atom of carbon and one atom of oxygen. Carbon monoxide is odorless and tasteless and highly toxic to animals, including humans. Some people have died when this dangerous gas builds up in their houses or cars.

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ever recorded on Earth—for worldwide average temperature—have occurred in the past decade or so. Carbon, in the form of carbon dioxide, enters the atmosphere in many ways. For instance, nearly all organisms on Earth are carbon-based, so when an organism dies, the carbon in its cells is released into the atmosphere. However, humans have accelerated that process. Clear-cutting large tracts of forests can release a tremendous amount of carbon into the atmosphere. Plus, removing so many trees also removes the benefit that trees and other plants have on the balance of carbon in the atmosphere. Trees remove carbon dioxide from the atmosphere. Today, the main source of atmospheric carbon is from the burning of fossil fuels such as coal, natural gas, and petroleum products. Because of this, the development of alternative sources of fuel and energy—ones that do not rely on the burning of fossil fuels— has become a priority for many nations around the world. Forms of Carbon When looking at the chemical and physical properties of carbon, we have to talk about allotropes. Allotropes of an element are the The Chemistry of Everyday Elements

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different forms that an element can take. Some of the best-known allotropes in chemistry are those of carbon. Carbon can exist in different forms including graphite, diamond, charcoal, coke, and fullerenes. Each of these are pure carbon, but they have different physical and chemical properties depending on how the atoms of carbon are arranged in them. For instance, charcoal is an impure form of carbon resulting from the combustion of wood in an environment lacking oxygen. Coke is fuel usually made from coal with a high concentration of carbon, and is commonly man-made. Charcoal black is the result of the combustion of petroleum products such as coal tar. The tiny bits of the carbon form of diamond make these drill bits very powerful.

Diamond and graphite are two of the most com-

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Extraterrestrial Diamonds? Some scientists hypothesize that there could be large areas of liquid diamond on the surfaces of Neptune and Uranus. Carbon is abundant in the atmospheres of both planets. And the atmospheres exert significant pressure on the surfaces of the planets. The combination of those factors could make conditions ripe for creating diamonds.

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Familiar at campfires and picnics, charcoal is a very useful form of carbon.

mon forms of pure carbon. These minerals have very different properties—diamond is one of the hardest (if not the hardest) naturally occurring minerals on Earth. Graphite, on the other hand, is much less hard. Diamonds are used in industry, in cutting and grinding tools, due to the hardness of the mineral. (Of course, diamonds are also popular in jewelry; see Chapter 4). Graphite is used as a lubricant and, when mixed with clay, in pencil production. And yet, the chemical bonds that hold together the atoms of carbon in a diamond are weaker than those that hold together the carbon atoms in a sample of graphite. The carbon atoms in diamond are held together in a 3-D structure. The atoms in graphite are arranged in tightly bound sheets. 30

Greenhouse gases explained

The strength of the bonds helps determine other properties of the minerals as well, not just their shape. One of those properties is melting point. It takes a lower temperature to melt a diamond than it does to melt graphite. In fact, in the open air it is possible to melt a diamond at a temperature of about 1,300°F (700°C).

Text-dependent questions 1. What is the atomic number of carbon? 2. Briefly, why is the trapping of too much greenhouse gases bad for the Earth? 3. What is the hardest form of carbon?

Research Project After watching the video from the QR code, write a short report on greenhouse gases, including a Web-researched chart of the hottest worldwide average temperatures over the past 10 years.

The Chemistry of Everyday Elements

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Carbon and You

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ou are an organic, carbon-based life form. In the early 1800s, scientists classified chemical compounds as either inorganic or organic. Inorganic compounds, by their definition, were composed of minerals. Organic compounds were materials that came from living things. While not entirely incorrect, these definitions were not a true representation of these two types of compounds. Today, we define an inorganic compound as a substance that has two or more chemical elements, usually not carbon. Organic compounds are composed of carbon, along with hydrogen and sometimes some other elements. The importance of carbon in

WORDS TO UNDERSTAND

biomolecules any molecules that are present in a living organism

carbohydrates organic compunds such as sugars or starches that act as fuel for organisms

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all living things is indisputable. Carbon is a major component in our bodies and in the structure of all living things. The human body is about 18 percent carbon, the second most abundant element in our cells after oxygen. Most of the molecules in the cells of our body contain carbon—the water in our cells is really the only molecule without carbon. These molecules are called biomolecules. Biomolecules have a chain of carbon atoms bonded to one another. Other elements can bond off of this common carbon chain. The carbon chain is the building block for so many of the molecules that are essential to life. This includes molecules such as carbohydrates, fats, proteins, and nuclei acids. Sweet potatoes (pictured) are a healthy source of “carbs.” Carbon Builds New Cells Carbohydrates, such as glucose, starch, and sucrose, are formed from a ring of carbon and oxygen atoms. Carbohydrates are vital sources of energy for our cells and our entire bodies. Lipids, such as fats, store energy in the body and

The Chemistry of Everyday Elements

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are composed of long chains of carbon and hydrogen bonded together. Proteins are responsible for most of the function of cells and are responsible for the structure and function of the tissues and organs in the body. Carbon atoms are one of the four parts that make up any protein molecule. Our bodies are composed of trillions of cells. Cells, as individual units in the human body, can’t generate energy. They can, and do, get energy from food molecules and indirectly from the Sun. The Sun is ultimately the source of energy for nearly all cells. Cells of plants harness the Sun’s energy and

use it to make more complex molecules. Those more complex molecules, called carbohydrates, are what other cells, including the ones in our bodies, rely on for growth, metabolism, and reproduction. Where We Get Carbon The main way we get more carbon into our bodies for our cells to use is by breathing. The respiratory system is the site for the exchange of carbon and oxygen. When we breathe in air, the body uses the oxygen in the air, in combination with the glucose it has consumed in the foods we eat, to form energy. There are two waste products from this reaction: water and carbon dioxide. The process breaks down the glucose, in the presence of oxygen, creates energy, and releases the carbon back into the cell. Carbon dioxide by itself is ultimately toxic to cells. As blood passes by the body’s cells, it carries with it a new supply of oxygen. The oxygen passes from the blood stream into the walls of the cells. At the same time, the waste carbon dioxide passes out of the cell and into the blood stream. The blood is carried to the lungs, where the carbon dioxide is exchanged once again and passes out of the body as you exhale. Good air in, bad air out, as the saying goes. Carbon-based? More like carbon-essential.

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WORDS TO UNDERSTAND

alloy a mixture of metals and other elements nonrenewable resource a resource that is not replenished in a usable amount of time, it exists in a finite quantity

Carbon: CHAPTER 3

Carbon Combines

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arbon forms many, many compounds, more than any other element by far. The types of carbon compounds fall into three categories: carbides, organic carbon compounds, and inorganic carbon compounds.

Carbides: At room temperature, carbon is, for the most part, inert. That means it will not react with other elements. But at high temperatures, it can react with other elements and form compounds known as carbides. Carbides can form when carbon reacts with a metal, silica, or the element called boron. Usually, carbides are made by heating a metal with carbon or some other compound of carbon. For example, calcium carbide (CaC2) is made when calcium oxide (a metal) is heated in an electric furnace with a form of carbon called coke. Carbides have specific uses. For example, silicon carbide 37

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(SiC) is used as an abrasive as it is almost as hard as diamond. Tungsten carbide is used in the manufacturing of machine parts and tools. Iron carbide is found in steel and other alloys of iron. Organic Compounds: Organic compounds are formed when one or more atoms of carbon link with other elements. Most typically the other element is hydrogen, oxygen, or nitrogen. Most organic compounds are made by living organisms, but it is possible to make organic compounds in a laboratory setting. There are approximately nine million different organic compounds on Earth. In other words, just about everything you touch or deal with on a daily basis contains some sort of organic compound. Carbon and Hydrogen = Oil: One form of organic carbon compound most people are familiar with are compounds of carbon and hydrogen called hydrocarbons. Hydrocarbons are organic compounds made up only of carbon and hydrogen atoms. Substances like methane, ethane, propane, butane, and octane are all examples of hydrocarbons. These hydrocarbons are the main source of energy for civ38

Carbon-based petroleum can be refined into a host of products at plants like this.

ilizations around the world today. Typically, they are liquids and are used as fuel, although in a solid form they are the basis for asphalt. Hydrocarbons form over very long periods of time. The remains of microscopic organic material, plant and animal, settle out of water in a shallow, enclosed sea, swamp, lagoon, or lake. Typically, this material is destroyed by bacteria. However, if conditions are just right, the organic material becomes buried in an environment that lacks oxygen, then the bacteria do not destroy the organic material. Instead, the material piles up on the floor of the body of water and subsequently becomes buried by other sediment. Millions of years pass, and the carbon and hydrogen from the organic material turns to hydrocarbon and becomes trapped inside rock under the surface. This trapped hydrocarbon will take the form of a liquid or a gas. Pressure and temperature builds over millennia, to the point The Chemistry of Everyday Elements

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No New Fossil Fuels It takes millions and millions of years for animal and plant material to turn into petroleum. As a result, the world’s petroleum cannot be replenished within a human life span. Removing the hydrocarbons from the Earth and using them as fuel will eventually deplete the available supply. As a result, hydrocarbons like petroleum are a nonrenewable resources—once they are all used up . . . they’re gone. No more will be made to take their place. This is one reason why efforts to find a substitute for fossil fuels, such as wind power or solar energy, are so important.

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where the bonds in the carbon atoms are destroyed. The result of this is the formation of a very simple hydrocarbon molecule known as petroleum. This change in form causes an increase in pressure, which causes the rock around the petroleum to crack, allowing the

The oil and gas industry plays a huge part in world economics.

newly formed petroleum (in the form of either a liquid or a gas) to move upward toward the surface. It moves upward and spreads out into a pool suitable for drilling into. Experts find oil deposits by looking for these deposits of hydrocarbon. The Carbon Oxygen Cycle The relationship between carbon and oxygen is very intertwined, especially when it comes to the atmosphere. Oxygen and carbon are exchanged in a process known as the carbon cycle. The Chemistry of Everyday Elements

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The mix of sunlight and carbon dioxide creates oxygen and energy from plants.

Burning fossil fuels, the breathing of all living things, and the dead bodies of organic beings all send carbon into the atmosphere in the form of CO2. Other natural events, such as volcanic eruptions, or a forest fire that burns trees, will also release CO2 into the atmosphere. Carbon is removed from the atmosphere in different ways as well. The process of photosynthesis, by which plants make their own energy, removes carbon dioxide from the atmosphere. Some carbon leaves the atmosphere as it is absorbed by ocean water. This exchange of oxygen and carbon between living things, the soil, and the atmosphere is called the carbon-oxygen cycle. It is one of the major cycles that move materials and energy between living organisms, the surface of Earth, and the atmosphere. 42

In the air, underground, in our bodies, and in many parts of our lives, carbon combines with other key elements to play a series of vital, ongoing roles.

Text-Dependent Questions 1. What is silicon carbide used for? 2. Name a type of hydrocarbon. 3. Briefly, how is petroleum formed underground? Research Project The world continues to depend on fossil fuels, but people understand that we have to reduce our dependence on them. Research some alternatives to fossil fuels and find out how they are being used in your city or state.

Watch oil form underground

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WORDS TO UNDERSTAND

decay breakdown of an unstable isotope into a more stable form, usually associated with the release of energy

impervious unable to be breached or passed through isotope a form of an atom that has a different number of neutrons in the nucleus

stratosphere layer of the atmosphere that contains the ozone layer; it stretches from about 5 miles (8 km) to about 30 miles (48 km) above Earth’s surface

Carbon: CHAPTER 4

Carbon in Our World

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can’t live without it,” is a phrase that many people toss around lightly. “I can’t live without my phone,” they might say. Or, “I can’t live without my pets,” etc. Those might be things that people truly want, but could actually continue

living without. That same is NOT true of carbon. Virtually all life forms on Earth would not exist without carbon. Besides keeping us all alive, this amazing and versatile element also plays a huge role in many areas of the world as we know it. It is present in nearly everything we use or touch. Here are some of the most well-know uses of carbon in the world. Activated Carbon Activated carbon, also called activated charcoal, is a form of carbon with very high surface area. It is estimated that three 45

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grams of this form of carbon has the same surface area as a football field! Carbon, usually in the form of coal or wood, is treated with oxygen, which creates a highly porous substance. Water, other liquids, or gases can pass through the pore space in the activated carbon and interact. The carbon may absorb and remove impurities such as chloride, odors, or dyes, allowing the activated carbon to act as a filter. Activated carbon has been used to remove volatile organic compounds from the air, as well as trapping odors. Taking doses of activated carbon can also help people suffering from drug overdoses or poisoning. Carbon Nanotubes Nanotechnology is a relatively Activated charcoal pills can be used by doctors to treat people who have ingested poison.

new branch of science and engineering that deals with particles on the nanoscale—between 1 and 100 nano-

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Nanotechnology using carbon materials can help shrink computer chips even farther.

meters in size. By comparison, a normal sheet of paper is about 100,000 nm wide. A human hair is between about 80,000 and 100,000 nm thick. Nanotechnology can be applied to many different types of materials. One such application is with carbon. Carbon nanotubes are cylinders of carbon atoms that measure only nanometers in diameter. A very thin sheet of carbon atoms, arranged in hexagons, is rolled into a tube. In some cases, the carbon atoms can be arranged in the nanotube to create a substance that is about six times lighter, but hundreds of times stronger, than steel. Some carbon nanotubes are designed to be semiconductors used in electronics. Carbon nanotubes are much smaller and stronger than the silicon-based materials used in electronics such as computers today. The Chemistry of Everyday Elements

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Carbon Fibers Carbon fibers are very, very thin threads of carbon atoms. On average, these fibers have a diameter of between 5 and 10 micrometers. Thousands of fibers are bundled together into a mass that can be made into a fabric-like material. The fibers are very lightweight, resistant to high temperatures, can be very stiff and rigid, and can handle a lot of stress without tearing or breaking. These properties allow carbon fibers to be used in a variety of applications. Carbon fiber has made tennis racquets stronger, but also much lighter.

Reinforced

carbon fibers are used in spacecraft and in the airline industry to create lighter, more durable components.

Everyday

items such as tennis racquets, golf clubs, and skis are often made with some carbon fiber components. Testing is being done to 48

use carbon fibers to help make buildings and bridges less susceptible to earthquakes. Carbon fibers have been used in the automobile industry, making cars lighter and thus improving fuel efficiency. There is also an exciting connection between carbon fibers and the green energy industry in several ways. Carbon fibers have been used to strengthen the blades on wind

The blades of many wind turbines use forms of carbon fiber for strength.

turbines. The strength and lightweight nature of the fibers lets the blades be built longer and larger. Firefighting Carbon, in the form of carbon dioxide, is a very useful tool in fighting fires. Some fire extinguishers contain carbon dioxide. When activated, the carbon dioxide is discharged in a white foamy cloud. The carbon dioxide displaces the oxygen that is feeding the fire. The gas is also under great pressures in the container and comes out in a very cool cloud. The drop in temperature helps to cool the fuel that is The Chemistry of Everyday Elements

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burning, helping to stop the fire. Carbon dioxide extinguishers are designed to fight flammable liquid and electrical fires only. Plastics

Fire extinguisher in action

Most of the plastic we use in our daily lives is composed of large, organic molecules. These organic molecules, or polymers, contain a chain of carbon that may also have atoms of oxygen, sulfur, or nitrogen. Plastics are inexpensive to manufacture, are impervious to water and most other liquids, and can be molded and shaped into different forms. This is why plastic products have replaced other materials such as wood, paper, metal, and glass in our everyday lives, and in industries such as automotive, aircraft, and health care. Because of the carbon-based composition of plastics, people are now concerned with the carbon footprint of plastic goods. For example, studies have indicated that, on average, for every kilogram of plastic manufactured and then incinerated after use, 6 kilograms of 50

Making plastic releases carbon dioxide; recycling can reduce plastic production.

carbon dioxide are released into the atmosphere. (Remember, that burning anything with carbon releases this gas.) Keeping this in mind should cause us to pause and bottles, considering the impact they have on the environment. Carbon Dating Carbon can be used to determine the age of many materials, including archaeological artifacts used by humans in the past 40,000 years. This includes bones that were shaped into tools, remains of wooden structures or fires, and plant remains. It can also be used to determine the age of skeletons and bodies buried long ago. The half-life of carbon-14, an isotope of carbon, is 5,730 years. This means that in a sample containing C-14, half of the molecules of C-14 will decay in that amount of time. It will take another 5,730 The Chemistry of Everyday Elements

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Carbon Neutral What does it mean to be carbon neutral? When an individual, an organization, or a nation is carbon neutral, it means that they are offsetting the amount of carbon they use or produce with something that balances that use. Offsets are one way to take responsibility for the greenhouse gases (particularly carbon dioxide) that we use when we burn fossil fuels. Carbon offsets are credits that can be

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used to compensate for emissions. Some industries, such as those that generate electricity using windmills, sell carbon offsets. Buying a carbon offset from a wind energy company helps that company make their projects. The individuals or corporations that buy the credit can then say that their purchase helped create new energy that does not pollute the environment, which will essentially cut back on the greenhouse gases they are creating. Wind energy is one example of an industry offering carbon offsets. Other examples of renewable energy sources are solar, hydroelectric, geothermal systems, and biomass energy. Organizations, governments, and individuals have pledged to become carbon neutral. Norway pledged to be carbon neutral by 2030. Costa Rica is working to hit that goal by 2021. The United Parcel Service (UPS) has a carbon neutral option for shipping. Check with your local energy provider to see if there are carbon neutral options for your electricity.

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years for half of what remains to decay, and so on. Knowing this fact, scientists using radiocarbon dating can determine the age of most materials containing carbon that are less than 60,000 years old. For instance, when a plant or another organism is alive, it has roughly the same amount of C-14 in its body as there is in the atmosphere (which is not a lot). Once the organism dies, the amount of C-14 is fixed in its remains. That C-14 can be measured and calculations done to determine when the organism died, thus providing a date of its origin. This type of dating is used often in archaeological studies. Thanks to carbon, scientists have Carbon dating is used by paleontologists to determine the age of fossils, like this very ancient fish.

been able to determine the age of some insects trapped in amber, of prehistoric papy-

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rus writing, and of charcoal fragments left behind by early humans. Carbonation Fizzy and bubbly drinks such as soda and seltzer water are carbonated. You can see the element in the name. The fizzy or effervescent quality of these drinks is the result of

Thank carbon for the fizzy bubbles in soda. Those bubbles are formed by escaping carbon dioxide.

adding carbon, in the form of carbon dioxide, to a liquid. In addition to the enjoyment of having a fizzy drink, there are other reasons to carbonate a beverage. The introduction of carbon dioxide into a beverage replaces the oxygen that might be in the liquid. This means, when sealed, the liquid has a longer shelf life. Any microbes that might grow in there need oxygen to survive. Replacing the oxygen with carbon dioxide prevents their growth, as long as the container remains sealed. For sodas, the CO2 is added during production of the drink. Carbonation can be a natural process, too. Beverages that are fermented, such as beer, use yeast in their production. Yeast is a single-celled The Chemistry of Everyday Elements

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fungus that undergoes fermentation. This is a process that changes sugar into alcohol and carbon dioxide. The carbon dioxide that forms as a result of fermentation gives the bubbly form to many types of beer as well as leaving holes and bubbles in breads and some cheeses.

The chemical process of fermentation makes carbon dioxide that forms these holes.

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CFCs were used in fire extinguishers, but studies found the gases were harmful.

CFCs and HFCs Chlorofluorocarbons, or CFCs, are chemical compounds made only of chlorine, fluorine, and, of course, carbon. CFCs were developed in the 1930s as a refrigerant. Refrigerants are chemicals that provide a method of cooling in a system that transfers heat (such as a refrigerator or air conditioner). CFCs were considered at the time to be perfect for uses in the home, in businesses, and in automobiles because they were nontoxic, nonflammable, and did not react with other compounds. Other uses of CFCs included use in aerosol cans, in some cleaning solvents, fire extinguishers, Styrofoam food packaging, and in electrical components. In 1973, it was discovered that the chlorine in the CFCs destroys ozone molecules. Ozone is a form of oxygen that exists in Earth’s atmosphere. It plays a huge role in protecting the Earth from The Chemistry of Everyday Elements

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Older air conditioners like this model should be replaced with newer models that don’t use CFCs.

dangerous levels of solar radiation. The CFCs were creating an “ozone hole” that was letting in

deadly rays. So, in 1989, the Montreal Protocol on Substances That Deplete the Ozone Layer went into effect. This international agreement was intended to control a group of hydrocarbons and other ozone-depleting substances, such as CFCs, that were known to be re58

Officials from around the world created a new HFC reduction agreement.

moving the ozone layer. As a result of these efforts, the thinning ozone layer in the stratosphere has begun to regenerate. But the replacement for CFCs turned out to be bad as well. So in 2016, a new agreement was reached to stem the use of that replacement, called hydroflourocarbons (HFCs). It turned out that HFCs had an unexpected, and dangerous, side effect. In the atmosphere, the HFCs trapped heat. The New York Times said that HFCs had “1,000 times the heat-trapping [power] of carbon dioxide.” More than 170 nations signed an agreement to phase out HFCs in new machines. Over time, this could greatly help reduce the temperature of the atmosphere, a climate change that has terrible possible The Chemistry of Everyday Elements

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Everything in this picture depends on some form of carbon to exist.

consequences for our future. The agreement predicts that this one step could take 70 billion tons of carbon from the atmosphere, more than two times the pollution now being produced. The full agreement will take decades to complete, but it was an important step in the continuing war on climate change. As we’ve seen, carbon is absolutely vital to life on Earth, as well as a key ingredient in many things we need and use to survive. But like 60

anything, it needs to be used in the right way so that effects of its use don’t cause more harm than good.

Text-Dependent Questions 1. What are three different methods of hydrogen production? 2. Why isn’t hydrogen fuel cell technology already widespread? 3. Why does it make sense to call fusion technology a “sun in a bottle”? Research Project Choose an industry or product that uses hydrogen, such as fertilizer or oil refining. Research hydrogen’s role in the process. How much hydrogen is used? Where does it come from? If it’s involved in a chemical reaction, how does the reaction work? How important is hydrogen to that industry or product?

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FIND OUT MORE

Books Boysen, Earl, and Nancy C. Muir. Nanotechnology for Dummies. New York: For Dummies, 2011. Challoner, Jack. The Elements: The New Guide to the Building Blocks of Our Universe. London: Carlton Books, 2012. Farndon, John. Oil. New York, NY: DK Publishing, 2012. Terrazas, April Chloe. Botany: Plants, Cells, and Photosynthesis. Austin, TX: Crazy Brainz, 2014.

Web Sites www.nano.gov/ Want to learn more about nanotechnology? Click on this site: www.carbonfootprint.com/calculator.aspx What to see how much impact you have on the environment? Try this carbon footprint exercise. www3.epa.gov/climatechange/kids/basics/today/greenhouseeffect.html This website, put out by the Environmental Protection Agency, is a great resource for information about the greenhouse effect.

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SERIES GLOSSARY OF KEY TERMS

carbohydrates a group of organic compounds including sugars, starches, and fiber that provide energy to organisms conductivity the ability of a substance for heat or electricity to pass through it inert unable to bond with other matter

ion an atom with an electrical charge due to the loss or gain of an electron isotope an atom of a specific element that has a different number of neutrons; it has the same atomic number but a different mass nuclear fission process by which a nucleus is split into smaller parts, releasing massive amounts of energy nuclear fusion process by which two atomic nuclei combine to form a heavier element while releasing energy organic compound a chemical compound in which one or more atoms of carbon are linked to atoms of other elements (most commonly hydrogen, oxygen, or nitrogen) solubility the ability of a substance to dissolve in a liquid spectrum the range of electromagnetic radiation with respect to its wavelength or frequency; can sometimes be observed by characteristic colors or light

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INDEX activated carbon 45 buckminsterfullerene 18 “buckyballs” 17 C60 17 carbides 37 carbonation 55, 56 carbon and biology 32, 33, 34, 35 carbon dating 51, 54 carbon dioxide 24, 25, 35, 41, 42, 52, 53 carbon fiber carbon, 48, 49 carbon, forms of 28 carbon monoxide 26 carbon, name of 12

carbon neutral 52, 53 charcoal 12, 13, 30 CFCs 57, 58 diamonds 14, 28, 30 Egyptians 12, 13 firefighting 49, 50 Fuller, Buckminster 19 geodesic domes 19 graphite 13, 28 greenhouse gases 25, 27, 52, 53 HFCs 57 Hippocrates 13 Lavoisier, Antoine 13, 15 Montreal Protocol 58

nanotubes 46 Neptune 29 oil 15, 16, 38, 39, 41 organic compounds 38 Pennsylvania 16 Phoenecians 13 Sumerians 12 Tennant, Smithson 15 University of Kentucky Center for Applied Energy Research 11 Uranus 29 West Virginia 15

Photo Credits

Adobe Images: Andrey 24, martingaal 31. Dreamstime.com: Bobyramone 7, Benkrut 19t, Bhairav 22, designua 25, Xneo 26, Manon Riguette 33, Jessamine 34, Alexander Levchenko 36, Molimar 39, lifede 40, seesea 41, IgOrsh 42, Akvals 44, Gulaper 46, Elder Salles 48, Maxfx 49, Huguette Roe 50, Judith Bicking 52, Nmint 53, Jadedme 54, Seandad 55, Anna1311 56, Zoransimin 57, John Wolf 58, Solarseven 60. Georgia Tech: 47. NASA: 10, 29. US State Department: 59. Wikimedia: 12, 14, 15, 16, Andreykor 17, XRDodRX 18, Michael Strick 20, junkyardsparkle 28.

About the Author Jane P. Gardner has written more than 30 books for young and young adult readers on science and other nonfiction topics. She wrote the Science 24/7 series and several titles in the Black Achievements in Science series. In addition to her writing career, she also has years of classroom teaching experience. Jane taught middle school and high school science and currently teaches chemistry at North Shore Community College in Massachusetts. She lives in eastern Massachusetts with her husband and two sons.

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