Name Class Date. Branched chain The chain of carbon atoms branches when a carbon atom bonds to more than two other carbon atoms.

Transcription

1 Name lass Date APTER 3 4 Organic ompounds SETION hemical ompounds BEFORE YOU READ After you read this section, you should be able to answer these questions: Why are there so many organic compounds? What are the names and the properties of organic compounds? What organic compounds are found in living things? National Science Education Standards PS 1a, 1b, 1c ow Does arbon Form ompounds? Most of the chemical compounds that exist contain carbon. These compounds are called organic compounds. Organic compounds are compounds made of molecules in which carbon atoms are covalently bonded to other atoms. Every organic compound contains carbon. arbon atoms have four outer electrons. This means that each carbon atom can make four covalent bonds with other atoms. Most organic molecules have two or more carbon atoms linked to one another. The illustrations in the figure below are models of organic molecules. These models are called structural formulas. They show the order in which atoms in a molecule are connected to one another. A line between two element symbols represents a covalent bond, or one pair of shared electrons. Models of Organic Molecules STUDY TIP Brainstorm With a partner, write down the names of several of your favorite foods. After you have read about the carbohydrates, lipids, and proteins, identify which of these groups are in the foods. READING EK 1. Identify What do most organic molecules have in them? Straight chain arbon atoms are connected one after another. Branched chain The chain of carbon atoms branches when a carbon atom bonds to more than two other carbon atoms. Ring The chain of carbon atoms forms a ring. TAKE A LOOK 2. Identify What are three ways carbon atoms link together in organic molecules? Notice that these molecules have chains of carbon atoms linked to one another. Some organic molecules have hundreds or thousands of carbon atoms linked together to form a backbone of the molecule. opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 49 hemical ompounds

2 Name lass Date SETION 4 Organic ompounds continued READING EK 3. Describe What are hydrocarbons? What Are Some Kinds of Organic ompounds? Many organic compounds contain atoms of several elements. The simplest organic compounds only contain two elements carbon and hydrogen. Organic compounds that contain only carbon and hydrogen are called hydrocarbons. ydrocarbons are grouped based on the covalent bonds between the carbon atoms, as shown in the figure below. Three Types of Bonds Between arbon Atoms Single Bond Double Bond Triple Bond TAKE A LOOK 4. Identify What are three types of hydrocarbons? READING EK 5. Describe ow do saturated and unsaturated hydrocarbons differ? The propane in a camping stove contains only single bonds. Fruits make ethene, which is a compound that helps ripen the fruit. Ethyne is better known as acetylene. It is burned in miners lamps and in welding torches. In some hydrocarbon molecules, each carbon atom shares one pair of electrons with each of four other atoms. This type of chemical bond is called a single bond. A hydrocarbon that has only single bonds is called a saturated hydrocarbon. It is also called an alkane. In an unsaturated hydrocarbon, at least one pair of carbon atoms shares more than one pair of electrons. A double bond is a covalent bond with two pairs of shared electrons. A triple bond has three pairs of shared electrons. When unsaturated organic molecules react, part of the double or triple bond can be broken. Other atoms can then be added to the molecule. ydrocarbons that contain a double bond are called alkenes. ydrocarbons that contain triple bonds are called alkynes. Alkenes and alkynes are unsaturated hydrocarbons. Benzene is a compound that has six carbon atoms in a ring shape. It is found in most of the compounds that are called aromatic compounds. In addition to hydrocarbons, there are many other kinds of organic compounds. These compounds are made by adding atoms of other elements to hydrocarbons. The other elements include the halogens, oxygen, sulfur, and nitrogen. opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 50 hemical ompounds

3 Name lass Date SETION 4 Organic ompounds continued What Organic hemicals Are Important to Life? Organic chemicals that are made by living things are called biochemicals. There are four important groups of biochemicals: carbohydrates, lipids, proteins, and nucleic acids. ARBOYDRATES arbohydrates are biochemicals that are made of one or more simple sugar molecules. Living things use carbohydrates as an energy source. There are two types: simple carbohydrates and complex carbohydrates. The figure below shows how atoms and molecules form carbohydrates. ellulose Straight chain Glycogen Branched chain O 2 O O O Glucose O O STANDARDS EK PS 1c hemical elements do not break down during normal laboratory reactions involving such treatments as heating, exposure to electric current, or reactions with acids. There are more than 100 known elements that combine in a multitude of ways to produce compounds, which account for the living and nonliving substances that we encounter. Word elp: chemical of or having to do with the properties or actions of substances Word elp: involve to have as a part of 6. ompare What are four groups of biochemicals important for living things? Glucose is a simple carbohydrate. ellulose and glycogen are complex carbohydrates made up of chains of glucose. Each hexagon in the diagram represents one glucose unit. The simple carbohydrates, including glucose, are made of carbon, hydrogen, and oxygen. The carbon atoms form a ring. omplex carbohydrates can have hundreds or thousands of sugar molecules held together by chemical bonds. ellulose is part of the rigid structure of the cell walls of plants. Animals use glycogen to supply energy to muscles. READING EK 7. Describe What are carbohydrates LIPIDS Lipids are biochemicals that do not dissolve in water. Fats, oils, and waxes are examples of lipids. One of the functions of lipids in living things is to store energy. It can be unhealthy to eat too many lipids, but some fats and oils are part of a healthy diet. Lipids store extra energy in the body. This energy can be used later when the lipids take part in chemical reactions. As the lipid molecules break down, they release the stored chemical energy. In general, animals use fats for this purpose and plants use oils. When the organism has used up its carbohydrates, it can obtain energy from its lipids. READING EK 8. Describe What are lipids? opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 51 hemical ompounds

4 Name lass Date SETION 4 Organic ompounds continued Vegetable oil, meat, cheese, eggs, and milk are sources of lipids in your diet. READING EK 9. Describe What are proteins? Say It Research Find out how hemoglobin can pick up and carry oxygen to the cells of the body. Report your finding to the class. PROTEINS Most of the biochemicals found in living things are proteins. Proteins are biochemicals that are made of chains of building blocks called amino acids. Amino acids are small molecules made of carbon, hydrogen, oxygen and nitrogen. Some amino acid molecules also have sulfur atoms. Protein molecules are made of hundreds or thousands of amino acid molecules. hemical bonds hold them together in long chains or complex webs. The function of a protein molecule depends on its shape. The shape of the protein molecule is determined by the exact order of amino acids in its structure. Proteins have many functions in living organisms. Enzymes are proteins that increase the rate of chemical reactions in a cell. emoglobin is a protein in red blood cells that carries oxygen to the cells of the body. Proteins help carry materials through cell membranes Some proteins provide structure and strength. Your hair and fingernails are made of protein molecules. The muscles that control the movement of your body are made primarily of protein molecules. Spiders use long chains of protein molecules to build light, but strong, silk webs. Spider webs are made up of proteins that are shaped like long fibers. opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 52 hemical ompounds

5 Name lass Date SETION 4 Organic ompounds continued NULEI AIDS The largest molecules made by living things are nucleic acids. Nucleic acids are biochemicals made up of nucleotides. Nucleotides are molecules made of carbon, hydrogen, oxygen, nitrogen and phosphorus atoms. There are only five different types of nucleotides. They are combined in chains of up to millions of units in nucleic acids. The order of the nucleotides determines the nucleic acid, just as the order of letters in a word determines the word. One of the functions of nucleic acids is to store genetic information. They are sometimes called the blueprints of life because they contain all of the information a cell needs to work. The patterns of the nucleotides are used by a cell when it builds proteins and other nucleic acids. READING EK 10. Describe What are nucleic acids? DNA AND RNA There are two kinds of nucleic acids: DNA and RNA. DNA molecules contain the genetic material of a cell. The DNA molecules in a single human cell contain millions of nucleotides and are about 2 meters long. This size allows the DNA molecules to store all of the information that a body s cells need to function. DNA molecules are shaped as a double spiral, as shown in the figure below. Each nucleotide in one spiral matches a specific nucleotide in the other spiral. When a cell needs to make a particular protein, information is copied from part of the DNA molecule. A second kind of nucleic acid, called RNA, is built using this information. The RNA molecule contains the information that the cell needs to build the protein molecules. RNA is involved in the actual building of proteins. READING EK 11. Describe What is stored in a DNA molecule? READING EK 12. Describe What information does an RNA molecule contain? Two strands of DNA are twisted in a spiral shape. Four different nucleotides make up the rungs of the DNA ladder. opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 53 hemical ompounds

6 Name lass Date Section 4 Review SETION VOABULARY carbohydrate a class of energy-giving nutrients that includes sugars, starches, and fiber; contains carbon, hydrogen, and oxygen hydrocarbon an organic compound composed only of carbon and hydrogen lipid a type of biochemical that does not dissolve in water; fats and steroids are lipids NSES PS 1a, 1b, 1c nucleic acid a molecule made up of subunits called nucleotides organic compound a covalently bonded compound that contains carbon protein a molecule that is made up of amino acids and that is needed to build and repair body structures and to regulate processes in the body 1. Identify omplete the following table. Type of carbon backbone Description The chain of carbon atoms forms a ring. All carbon atoms are connected in a straight line. The chain of carbon atoms separates into different directions. 2. Explain What group of hydrocarbons contains saturated compounds? What groups of hydrocarbons contain unsaturated compounds? 3. Identify omplete the following table. Type of biochemical Description made of hundreds or thousands of amino acid molecules one of the functions is to store genetic information made of one or more simple sugar molecules one of the functions in living things is to store energy 4. Identify and Describe What are two kinds of nucleic acids? What does each one do in living things? opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook 54 hemical ompounds

7 L Interactions of Matter Answer Key continued SETION 2 AIDS AND BASES 1. A hydrogen ion bonds with a water molecule to form the hydronium ion. 2. sour taste 3. The left beaker should be colored blue, and the right beaker yellow. 4. hydrogen gas and zinc chloride 5. ions 6. making fertilizers 7. Acids produce hydronium ions, and bases produce hydroxide ions. 8. hydroxide ions 9. It could hurt you because chemicals such as acids and bases can be corrosive or poisonous. 10. The left beaker should be colored pale blue, and the right beaker dark blue. 11. blue 12. household cleaners and fertilizers Review 1. Acids produce hydronium ( 3 O + ) ions, and bases produce hydroxide (O ) ions. 2. Property Acids Bases Taste sour bitter olor change of litmus paper Reaction with metals to produce hydrogen gas Electrical conductivity 3. hydronium to red yes yes to blue no yes 4. No, because acids and bases both conduct electricity. 5. It turns blue because ammonia is a base. 6. The acid or base is corrosive. 7. A base; rinse them with lots of water and tell the teacher. SETION 3 SOLUTIONS OF AIDS AND BASES 1. the amount of acid or base dissolved in water 2. A strong acid has more molecules that break apart when you dissolve the acid in water than a weak acid does. 3. water and a salt 4. p is the amount of hydronium ions in a solution. 5. Bases have high p value, and acids have low p. 6. acid rain 7. when a positive ion from a base combines with a negative ion from an acid 8. table salt and melting snow and ice Review 1. In water, all the molecules of a strong acid break apart and form hydronium ions. When a weak base is dissolved in water, only a few molecules break off to form hydroxide ions. 2. When an acid and base combine, there is a neutralization reaction. The hydrogen ions from the acid combine with the hydroxide ions from the base to form water and a salt. 3. Sodium hydroxide hydrochloric acid water sodium chloride 4. with p paper or a p meter 5. The p would be around 9 because bases have high p values. The stronger the base, the higher the p value. 6. A p value below 7 indicates an acid; the lower the number, the more acidic. This would be a bad place for fish to live, because the water is too acidic. SETION 4 ORGANI OMPOUNDS 1. two or more carbon atoms linked to one another 2. straight chain, branched chain, ring 3. organic compounds that contain only carbon and hydrogen 4. alkanes, alkenes, and alkynes 5. Saturated hydrocarbons have only single covalent bonds between carbon atoms. Unsaturated hydrocarbons have double or triple covalent bonds between carbon atoms. 6. carbohydrates, lipids, proteins, nucleic acids 7. biochemicals that are made of one or more simple sugar molecules 8. biochemicals that do not dissolve in water; store energy 9. biochemicals that are made of chains of building blocks called amino acids 10. biochemicals made up of nucleotides 11. all of the information that a body s cells need to function opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook Answer Key 78 Interactions of Matter

8 L Interactions of Matter Answer Key continued 12. the information that the cell needs to build protein molecules Review 1. Type of carbon backbone Ring Straight chain Branched chain Description The chain of carbon atoms forms a ring. All carbon atoms are connected in a straight line. The chain of carbon atoms separates into different directions. 2. saturated compounds alkanes, unsaturated compounds alkenes and alkynes 3. Type of biochemical Description Proteins Nucleic acids arbohydrates Lipids made of hundreds or thousands of amino acid molecules one of the functions is to store genetic information made of one or more simple sugar molecules one of the functions is to store energy 4. DNA contains the genetic material of a cell; RNA contains the information that the cell needs to build protein molecules. hapter 4 Atomic Energy SETION 1 RADIOATIVITY 1. Energy came from the uranium. 2. radioactive decay 3. An alpha particle has two protons and two neutrons. Mass number is the sum of the protons and neutrons in a nuclear particle or in a nucleus mass and charge 6. It stays the same atoms that have the same number of protons but different number of neutrons 9. high-energy waves 10. They have more mass and charge, so they tend to interact with atoms more easily. 11. They penetrate matter deeply. 12. to warn them if they have been exposed to radiation harmful enough to damage cells 13. follow the path of a process 14. Dark area should be circled. 15. heck for leaks in pipes and flaws in metal objects. 16. carbon one half-life, two half-lives 18. A little less than half of the carbon-14 had decayed after his death. Review 1. The atomic number for both isotopes is 92. The mass number of uranium-235 is 235, and the mass number of uranium-238 is First column, top to bottom: alpha, beta, gamma Second column: particle (electron) Third column, top to bottom: 4, 0 Fourth column, top to bottom: 1-, 0 Last column, top to bottom: low, high 3. Gamma rays would work because they have the most penetrating power and enough energy to pass through metal. Alpha and beta particles would be stopped by the metal parts. 4. One-fourth remaining indicates 2 half-lives or 2.6 billion years. SETION 2 ENERGY FROM TE NULEUS 1. A large nucleus splits into two smaller nuclei, releasing energy. 2. Their difference is three because three neutrons are also produced. 3. Some of the masses are changed into energy. 4. a continuous series of nuclear fission reactions 5. by keeping some of the neutrons from hitting a uranium nucleus 6. kinetic energy changed into mechanical energy, mechanical energy changed into electrical energy 7. An explosion can blow a large amount of radioactive fuel and waste into the atmosphere. 8. It has dangerous levels of radioactivity. 9. carbon dioxide 10. Two or more nuclei that have small masses combine to form a larger nucleus. 11. the core 12. Scientists cannot yet control the high temperatures well enough to use fusion. opyright by olt, Rinehart and Winston. All rights reserved. Interactive Textbook Answer Key 79 Interactions of Matter