chapter 8 carbon chemistry chapter preview questions 1.a chemical bond is a. a way of organizing...

Chapter 8 Carbon Chemistry

Chapter Preview Questions

1. A chemical bond is

a. a way of organizing elements in the periodic table.

b. the force that holds two atoms together.

c. how elements react with each other.

d. a result of combustion.



2. The ways in which an atom can bond with other atoms depends on the atom’s

a. valence electrons.

b. nucleus.

c. atomic number.

d. atomic mass.



3. In a carbon dioxide molecule (CO2), carbon forms a(n)

a. ionic compound with oxygen.

b. atomic number.

c. polyatomic ion.

d. double bond with each of two oxygen atoms.



4. The most loosely held electrons in an atom are

a. unstable electrons.

b. covalent electrons.

c. valence electrons.

d. low-energy electrons.


Natural gas contains mostly

methane (CH4), a compound

made of carbon and hydrogen.

When methane burns, is energy

absorbed or released?

How do you know?

Why does carbon have a central role in the chemistry of living organisms?


Section 1: Properties of Carbon

Standard 8.6.a Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.


Carbon Atoms and Bonding

Why does carbon play a central role in the chemistry of living organisms?

Because of its unique ability to combine in many ways with itself and other elements, carbon has a central role in the chemistry of living organisms.



With four valence electrons, each carbon atom is able to form four bonds. Carbon atoms can form straight chains, branched chains, and rings.



Carbon atoms and the bonds between them can be modeled in several ways.


Forms of Pure Carbon

What are the four forms of pure carbon?

At very high temperatures and pressures, carbon atoms can form diamonds.




Another form of the element carbon is graphite. In graphite, each carbon atom is bonded tightly to three other carbon atoms in flat layers.




In 1985, scientists made a new form of carbon, a fullerene. It consists of carbon atoms arranged in the shape of a hollow sphere.




In 1991, scientists made another form of carbon, a nanotube. It consists of carbon atoms arranged in the shape of a long, hollow tube.


Section 1 Quick QuizWhat is the shape of pure carbon fullerenes?

A. flat layers

B. hard, solid crystal shaped like a ball

C.hollow tube

D.hollow ball with a pattern like a geodesic dome

Answer – D – hollow ball with a pattern like a geodesic dome


Section 1 Quick QuizWhich form of pure carbon is formed of layers that slide past one another?

A.graphite

B.diamond

C.fullerene

D.nanotube

Answer – A - graphite


Section 1 Quick QuizHow many chemical bonds can each carbon atom form?

A.one

B.two

C.three

D.four

Answer – D - four


Section 1 Quick QuizWhich form of pure carbon is so hard that it can be used in cutting tools?

A.graphite

B.diamond

C.nanotube

D.fullerene

Answer – B - diamond


Section 1 Quick QuizIn a nanotube, carbon atoms are arranged in

A.the shape of a hollow sphere.

B.the shape of a spiral ladder.

C.the shape of a long, hollow cylinder.

D.flat layers.

Answer – C – the shape of a long, hollow cylinder


Section 1 Quick QuizCarbon is able to bond with atoms of other elements in many different ways because it has

A.four valence electrons.

B.six valence electrons.

C.six protons.

D.four electrons.

Answer – A – four valence electrons


Section 2: Carbon Compounds

Standard 8.3.c Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.

Standard 8.6.a Students know that carbon, because of its ability to combine in many ways with itself and other elements, has a central role in the chemistry of living organisms.


Organic CompoundsWhat are some similar properties shared by organic compounds?

organic compounds

Many organic compounds have similar properties in terms of melting points, boiling points, odor, electrical conductivity, and solubility.

Carbon compounds are so numerous that they are given a specific name. With some exceptions, compounds that contain carbon are called organic compounds.


Organic CompoundsWhat are some properties of hydrocarbons?

hydrocarbon

Like many other organic compounds, hydrocarbons mix poorly with water. Also, all hydrocarbons are flammable.

A compound that contains only the elements carbon and hydrogen.

Examples:Methane – CH4 (natural gas)

Ethane – C2H6

Propane – C3H8


Structure and Bonding in Hydrocarbons

What kind of structures and bonding do hydrocarbons have?

Structural Formula

The carbon chains in a hydrocarbon may be straight, branched, or ring-shaped.

A structural formula shows the kind, number, and arrangement of atoms in a molecule.


Boiling Points of Hydrocarbons

The graph shows the boiling points of several hydrocarbons. (Note: Some points on the y-axis are negative.)

Use the graph to answer the following questions.



Almost in the center of the y-axis

Reading Graphs:

Where is 0ºC on the graph?



C3H8: about –44ºC;C5H12: about 34ºC;C6H14: about 68ºC

Interpreting Data:

What is the approximate boiling point of C3H8? C5H12? C6H14?



About 78ºC

Calculating:

What is the temperature difference between the boiling points of C3H8 and C5H12?



C2H6, C3H8, and C4H10 are gases because their boiling points are below room temperature (about 22ºC). C5H12 and C6H14 may be liquids or solids, depending on their melting points.

Drawing Conclusions:

At room temperature (about 22ºC), which of the hydrocarbons are gases? How can you tell?



Compounds that have the same chemical formula but different structural formulas are called isomers. Each isomer is a different substance with its own characteristic properties.



In addition to forming a single bond, two carbon atoms can form a double bond or a triple bond.


Structure and Bonding in HydrocarbonsSaturated hydrocarbons

Unsaturated hydrocarbons

Hydrocarbons with only single bonds that have the maximum number of hydrogen atoms possible on their carbon chains

Hydrocarbons with double or triple bonds that have fewer hydrogen atoms for each carbon atom than saturated hydrocarbons.

In general, a chain hydrocarbon ending in –ane is saturated. A chain hydrocarbon ending in –ene or –yne is unsaturated.



What are some characteristics of substituted hydrocarbons?

If just one atom of another element is substituted for a hydrogen atom in a hydrocarbon, a different compound is created.

A hydrocarbon in which one or more hydrogen atoms have been replaced by atoms of other elements.

Substituted hydrocarbons include halogen-containing compounds, alcohols, and organic acids.


Substituted HydrocarbonsAlcohols

When a hydroxyl group (-OH) is substituted for a hydrogen atom in methane (CH4), methanol is formed.

A hydroxyl group (–OH) is made of an oxygen atom and a hydrogen atom. An alcohol is a substituted hydrocarbon that contains one more more hydroxyl groups.


Substituted Hydrocarbons

Organic Acids An organic acid is a substituted hydrocarbon that contains one or more carboxyl groups. A carboxyl group is written as –COOH.


Esters

What are some characteristics of esters?

An ester is a compound made by chemically combining an alcohol and an organic acid.

Esters are responsible for the smells of pineapples, bananas, strawberries, and apples.


Polymers

What are some characteristics of polymers?

A polymer is a very large molecule made of a chain of many smaller molecules bonded together.

The smaller molecules are called monomers.

Organic compounds, such as alcohols, esters, and others, can be linked together to build polymers with thousands or even millions of atoms.


Section 2 Quick QuizWhat is another name for carbon compounds?

A.hydrocarbons

B.fullerenes

C.organic compounds

D.carbohydrates

Answer – C – organic compouns


Section 2 Quick QuizCompounds that contain only the elements carbon and hydrogen are called

A.isomers.

B.carbon chains.

C.substituted hydrocarbons.

D.hydrocarbons.

Answer – D - hydrocarbons


Section 2 Quick QuizWhat can you tell about methane (CH4) from its molecular formula?

A.It contains four hydrogen atoms.

B.It contains four carbon atoms.

C.It forms groups of four molecules.

D.It contains one hydrogen atom.

Answer – A – It contains four hydrogen atoms.


Section 2 Quick QuizWhat property do all hydrocarbons have?

A.They dissolve in water.

B.They make good conductors of electricity.

C.They have high melting points.

D.They burn easily.

Answer – D – They burn easily.


Section 2 Quick QuizButane and isobutane have the same chemical formula (C4H10). However, butane is a straight chain, whereas isobutane is a branched chain. Butane and isobutane are examples of

A.monomers.

B.isomers.


D.unsaturated hydrocarbons.

Answer – B - isomers


Section 2 Quick QuizThe alcohol methanol (CH4OH) forms when one of the hydrogen atoms in methane (CH4) is replaced with a hydroxyl group (-OH). Alcohols are examples of

A.carbohydrates.

B.esters.



Answer – C – substituted hydrocarbons


Section 2 Quick QuizA very large organic molecule made up of chains of smaller molecules is called a

A.substituted hydrocarbons.

B.polymer.

C.monomer.

D.saturated hydrocarbon.

Answer – B - polymer


Section 3: Polymers and Composites

Standard 8.3.c Students know atoms and molecules form solids by building up repeating patterns, such as the crystal structure of NaCl or long-chain polymers.


Forming Polymers

How do polymers form?

Polymers form when chemical bonds link large numbers of monomers in a repeating pattern.


Polymers and CompositesNatural Polymers Plants, animals, and other living things produce many natural materials

made of large polymer molecules.

Cellulose is a flexible but strong natural polymer found in the cell walls of fruits and vegetables.

Proteins are polymers formed from smaller molecules called amino acids.


Polymers and Composites

Synthetic Polymers The properties of synthetic polymers make them ideal starting materials for many common objects.

The starting materials for many synthetic polymers come from coal or oil.

Plastics are the most common synthetic polymers.


Polymers and Composites

What are composites made of?

Many composites include one or more polymers.

A composite combines two or more substances in a new material with different properties.

Wood is a natural composite made of cellulose and lignin. The two polymers are weak by themselves, but they are strong when combined together.


Recycling PlasticsHow can you help reduce the amount of plastic waste?

You can help reduce the amount of plastic waste by recycling.

Plastics do not react very easily with other substances, so they do not degrade into simpler materials in the environment.


Section 3 Quick QuizWhich of the following is a polymer formed from smaller molecules called amino acids?

A.ester

B.protein

C.starch

D.cellulose

Answer – B - protein


Section 3 Quick QuizWood is a natural composite made of two plant polymers, lignin and cellulose. Without cellulose, a tree branch would probably

A.be as hard as steel.

B.be made of denser wood.

C.bend more easily in the wind.

D.snap more easily.

Answer – D – snap more easily


Section 3 Quick QuizWhich of the following statements about synthetic polymers is NOT true?

A.Synthetic polymers last a long time.

B.Synthetic polymers are inexpensive to make.

C.Synthetic polymers react easily with other substances.

D.Synthetic polymers increase the volume of trash.

Answer – C – Synthetic polymers react easily with other substances.


Section 4: Life With Carbon

Standard 8.6.b Students know that living organisms are made of molecules consisting largely of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.

Standard 8.6.c Students know that living organisms have many different kinds of molecules, including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA.


Life With CarbonWhat are four classes of organic compounds required by living things, and how are they used in the body?Carbohydrates

Proteins

The four classes of organic compounds required by living things are carbohydrates, proteins, lipids, and nucleic acids.The body breaks down starch into glucose, which is used by the body as energy to carry out its life functions.

The body uses proteins from food to build and repair body parts and to regulate cell activities.


Life With CarbonLipids Gram for gram, lipids release twice as much energy in your body as do carbohydrates.

Lipids include fats and oils. Fats are usually solid at room temperature, whereas oils are liquid.Cholesterol is a lipid used by the body to build cell structures and to form important compounds. An excess of cholesterol in the blood can contribute to heart disease.Cholesterol is often found in the same foods as saturated fats.Saturated fats can affect the level of cholesterol in the blood.


Life With CarbonNucleic Acids There are two types of nucleic acids, DNA and RNA.

DNA is made from four kinds of nucleotides.RNA is also made from four kinds of nucleotides, but the nucleotides in RNA differ from those in DNA.The differences among living things depend on the order of nucleotides in their DNA.When living things reproduce, they pass DNA and the information it carries to the next generation.


Other NutrientsWhy do organisms need water, vitamins, minerals, and salts?

Water

Vitamins

Minerals

Salts

Organisms require water, vitamins, minerals, and salts to support the functioning of large molecules.

Water makes up about 90 percent of the liquid part of blood. Nutrients are dissolved in the watery part of blood and carried throughout the body.

Vitamins serve as helper molecules in a variety of chemical reactions in the body.

Minerals are elements in the form of ions needed by the body.

Salts are ionic compounds that help the body in such processes as muscle contraction, bone growth, and pH balance.


The Molecules of Life

Complex carbohydrates, proteins, lipids, and nucleic acids are all large organic molecules. They are built of smaller molecules linked in different patterns.


Section 4 Quick QuizSubstances that provide the energy and raw materials the human body needs are

A.nutrients.

B.substituted hydrocarbons.

C.esters.


Answer – A - nutrients.


Section 4 Quick QuizThe classes of organic compounds found in all living things are

A.halogen compounds, alcohols, organic acids, and esters.

B.carbohydrates, lipids, proteins, and nucleic acids.

C.vitamins and minerals.

D.simple carbohydrates and hydrocarbons.

Answer – B – carbohydrates, lipids, proteins, and nucleic acids.


Section 4 Quick QuizWhich organic compound carries information from one generation to the next during reproduction?

A.carbohydrates

B.lipids

C.proteins

D.DNA

Answer – D - DNA


Section 4 Quick QuizGram for gram, which organic compounds release twice as much energy in your body as do carbohydrates?

A.vitamins

B.lipids

C.proteins

D.nucleic acids

Answer – B - lipids

chapter 8 carbon chemistry chapter preview questions 1.a chemical bond is a. a way of organizing...

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