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An endothermic chemical reaction is a reaction that releases energy. | (A) true (B) false | B | In an endothermic reaction, it takes more energy to break bonds in the reactants than is released when new bonds form in the products. The word "endothermic" literally means "taking in heat." A constant input of energy, often in the form of heat, is needed in an endothermic reaction. Not enough energy is released when ... |
how fast a reaction occurs | (A) activation energy (B) catalyst (C) concentration (D) endothermic (E) exothermic (F) reaction rate (G) chemical energy | F | How fast a chemical reaction occurs is called the reaction rate. Several factors affect the rate of a given chemical reaction. They include the: temperature of reactants. concentration of reactants. surface area of reactants. presence of a catalyst. |
The general equation for an exothermic reaction is Reactants + Energy Products. | (A) true (B) false | B | The word exothermic means releasing heat. Energy, often in the form of heat, is released as an exothermic reaction proceeds. This is illustrated in the Figure 1.1. The general equation for an exothermic reaction is: Reactants Products + Energy If the energy produced in an exothermic reaction is released as heat, it re... |
energy needed to start a reaction | (A) activation energy (B) catalyst (C) concentration (D) endothermic (E) exothermic (F) reaction rate (G) chemical energy | A | Chemical reactions also need energy to be activated. They require a certain amount of energy just to get started. This energy is called activation energy. For example, activation energy is needed to start a car engine. Turning the key causes a spark that activates the burning of gasoline in the engine. The combustion o... |
taking in heat | (A) activation energy (B) catalyst (C) concentration (D) endothermic (E) exothermic (F) reaction rate (G) chemical energy | D | Heat energy is transferred between physical entities. Heat is taken in or released when an object changes state, or changes from a gas to a liquid, or a liquid to a solid. This heat is called latent heat. When a substance changes state, latent heat is released or absorbed. A substance that is changing its state of matt... |
Plants synthesize glucose in an endothermic chemical reaction. | (A) true (B) false | A | One of the most important series of endothermic reactions is photosynthesis. In photosynthesis, plants make the simple sugar glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ) in the process. The reactions of photosynthesis are summed up by this chemical equation: 6 CO2 + 6... |
number of particles of a substance in a given volume | (A) activation energy (B) catalyst (C) concentration (D) endothermic (E) exothermic (F) reaction rate (G) chemical energy | C | Density is an important physical property of matter. It reflects how closely packed the particles of matter are. Density is calculated from the amount of mass in a given volume of matter, using the formula: Density (D) = Mass (M) Volume (V ) Problem Solving Problem: What is the density of a substance that has a mass of... |
The law of conservation of energy does not apply to chemical reactions. | (A) true (B) false | B | Whether a chemical reaction absorbs or releases energy, there is no overall change in the amount of energy during the reaction. Thats because energy cannot be created or destroyed. This is the law of conservation of energy. Energy may change form during a chemical reactionfor example, from chemical energy to heat energ... |
Any factor that helps reactants come together lowers the activation energy. | (A) true (B) false | A | Any factor that helps reactants come together so they can react lowers the amount of activation energy needed to start the reaction. If the activation energy is lowered, more reactant particles can react, and the reaction occurs more quickly. How fast a reaction occurs is called the reaction rate. Factors that affect t... |
All chemical reactions involve energy. | (A) true (B) false | A | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called exothermic reactions, more energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is ... |
One of the most important endothermic reactions is photosynthesis. | (A) true (B) false | A | One of the most important series of endothermic reactions is photosynthesis. In photosynthesis, plants make the simple sugar glucose (C6 H12 O6 ) from carbon dioxide (CO2 ) and water (H2 O). They also release oxygen (O2 ) in the process. The reactions of photosynthesis are summed up by this chemical equation: 6 CO2 + 6... |
In an exothermic reaction, it takes more energy to break bonds in reactants than is released when bonds | (A) true (B) false | B | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called exothermic reactions, more energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is ... |
Combustion is an example of an endothermic reaction. | (A) true (B) false | B | All combustion reactions are exothermic reactions. During a combustion reaction, a substance burns as it combines with oxygen. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in the Figure 1.2. The combustion of wood is an exothermic reaction that releases a lot of energy a... |
There is no overall change in the amount of energy in chemical reactions. | (A) true (B) false | A | Energy changes form when something happens. But the total amount of energy always stays the same. The Law of Conservation of Energy says that energy cannot be created or destroyed. Scientists observed that energy could change from one form to another. They also observed that the overall amount of energy did not change.... |
Only endothermic reactions need energy to get started. | (A) true (B) false | B | Some chemical reactions need a constant input of energy to take place. They are called endothermic reactions. Other chemical reactions release energy when they occur, so they can keep going without any added energy. They are called exothermic reactions. Q: It makes sense that endothermic reactions need activation energ... |
Energy is absorbed in exothermic reactions. | (A) true (B) false | B | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called exothermic reactions, more energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is ... |
An increase in temperature is a sign of an exothermic reaction. | (A) true (B) false | A | The word exothermic means releasing heat. Energy, often in the form of heat, is released as an exothermic reaction proceeds. This is illustrated in the Figure 1.1. The general equation for an exothermic reaction is: Reactants Products + Energy If the energy produced in an exothermic reaction is released as heat, it re... |
Products have less stored chemical energy than reactants in an endothermic reaction. | (A) true (B) false | B | All chemical reactions involve energy. Energy is used to break bonds in reactants, and energy is released when new bonds form in products. In some chemical reactions, called endothermic reactions, less energy is released when new bonds form in the products than is needed to break bonds in the reactants. The opposite is... |
Catalysts in living things are called enzymes. | (A) true (B) false | A | Chemical reactions constantly occur inside the cells of living things. However, under the conditions inside cells, most biochemical reactions would occur too slowly to maintain life. Thats where enzymes come in. Enzymes are catalysts in living things. Like other catalysts, they speed up chemical reactions. Enzymes are ... |
Cellulose is | (A) one of the most common compounds on Earth (B) made by the cells of plants and animals (C) a monomer of carbon (D) all of the above | A | Cellulose is another complex carbohydrate that is a polymer of glucose. However, the glucose molecules are bonded together differently in cellulose than they are in starches. Cellulose molecules bundle together to form long, tough fibers (see Figure 9.18). Have you ever eaten raw celery? If you have, then you probably ... |
How many more valence electrons does carbon need to fill its outer energy level? | (A) 1 (B) 2 (C) 3 (D) 4 | D | Carbon is a nonmetal in group 14 of the periodic table. Like other group 14 elements, carbon has four valence electrons. Valence electrons are the electrons in the outer energy level of an atom that are involved in chemical bonds. The valence electrons of carbon are shown in the electron dot diagram in the Figure 1.1. ... |
Which type(s) of bonds can a carbon atom form with other carbon atoms? | (A) single bonds (B) double bonds (C) triple bonds (D) all of the above | D | Carbon can form single, double, or even triple bonds with other carbon atoms. In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons. Examples of compounds with these types of bonds are shown in Figure... |
How many bonds can each carbon atom form? | (A) 1 (B) 2 (C) 3 (D) 4 | D | Carbon can form single, double, or even triple bonds with other carbon atoms. In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons. Examples of compounds with these types of bonds are shown in Figure... |
Forms of pure carbon include | (A) methane (B) cellulose (C) diamond (D) two of the above | C | Pure carbon can exist in different forms, depending on how its atoms are arranged. The forms include diamond, graphite, and fullerenes. All three forms exist as crystals, but they have different structures. Their different structures, in turn, give them different properties. You can learn more about them in Table 9.1. ... |
The plastic called polythene consists of | (A) repeating monomers of ethene (B) only carbon and hydrogen atoms (C) many fullerenes joined by covalent bonds (D) two of the above | D | Synthetic carbon polymers are produced in labs or factories. Plastics are common examples of synthetic carbon polymers. You are probably familiar with the plastic called polyethylene. All of the plastic items pictured in the Figure 1.3 are made of polyethylene. It consists of repeating monomers of ethylene (C2 H4 ). St... |
Forms of crystalline carbon include | (A) cotton (B) graphite (C) charcoal (D) methane | B | Graphite is one of three forms of crystalline, or crystal-forming, carbon. Carbon also exists in an amorphous, or shapeless, form in substances such as coal and charcoal. Different forms of the same element are called allotropes. Besides graphite, the other allotropes of crystalline carbon are diamond and fullerenes. A... |
One of the most common naturally occurring compounds on Earth is | (A) graphite (B) fullerene (C) cellulose (D) polythene | C | An element is a pure substance. It cannot be separated into any other substances. There are more than 90 different elements that occur in nature. Some are much more common than others. Hydrogen is the most common element in the universe. Oxygen is the most common element in Earths crust. Figure 3.7 shows other examples... |
The monomers in a polymer may be | (A) all the same (B) different from one another (C) joined by metallic bonds (D) two of the above | D | Carbon has a unique ability to form covalent bonds with many other atoms. It can bond with other carbon atoms as well as with atoms of other elements. Because of this ability, carbon often forms polymers. A polymer is a large molecule that is made out of many smaller molecules that are joined together by covalent bonds... |
Which statement about carbon is false? | (A) It has four valence electrons (B) It forms covalent bonds with other nonmetals (C) It is found in the majority of known compounds (D) It rarely forms large compounds called polymers | D | The short term cycling of carbon begins with carbon dioxide (CO2 ) in the atmosphere. |
All carbon polymers are | (A) naturally occurring (B) produced in labs (C) found in plastics (D) large molecules | D | Carbon has a unique ability to form covalent bonds with many other atoms. It can bond with other carbon atoms as well as with atoms of other elements. Because of this ability, carbon often forms polymers. A polymer is a large molecule that is made out of many smaller molecules that are joined together by covalent bonds... |
large molecule that consists of many smaller molecules joined together by covalent bonds | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | B | Carbon has a unique ability to form covalent bonds with many other atoms. It can bond with other carbon atoms as well as with atoms of other elements. Because of this ability, carbon often forms polymers. A polymer is a large molecule that is made out of many smaller molecules that are joined together by covalent bonds... |
form of carbon in which carbon atoms are arranged in layers | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | F | Pure carbon can exist in different forms, depending on how its atoms are arranged. The forms include diamond, graphite, and fullerenes. All three forms exist as crystals, but they have different structures. Their different structures, in turn, give them different properties. You can learn more about them in Table 9.1. ... |
one of the simplest carbon compounds | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | E | Carbon is a very common ingredient of matter because it can combine with itself and with many other elements. It can form a great diversity of compounds, ranging in size from just a few atoms to thousands of atoms. There are millions of known carbon compounds, and carbon is the only element that can form so many differ... |
form of carbon that it is the hardest natural substance | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | D | Diamond is a form of carbon in which each carbon atom is covalently bonded to four other carbon atoms. This forms a strong, rigid, three-dimensional structure (see Figure 1.1). Diamond is the hardest natural substance, and no other natural substance can scratch it. This property makes diamonds useful for cutting and gr... |
Carbon is a nonmetal in group 12 of the periodic table. | (A) true (B) false | B | Carbon is a nonmetal in group 14 of the periodic table. Like other group 14 compounds, carbon has four valence electrons. Valence electrons are the electrons in the outer energy level of an atom that are involved in chemical bonds. The valence electrons of carbon are shown in Figure 9.1. |
small molecule joined with other small molecules by covalent bonds to form a much larger molecule | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | A | Carbon has a unique ability to form covalent bonds with many other atoms. It can bond with other carbon atoms as well as with atoms of other elements. Because of this ability, carbon often forms polymers. A polymer is a large molecule that is made out of many smaller molecules that are joined together by covalent bonds... |
A structural formula uses dots to represent electrons. | (A) true (B) false | B | Because valence electrons are so important, atoms are often represented by simple diagrams that show only their valence electrons. These are called electron dot diagrams, and three are shown below. In this type of diagram, an elements chemical symbol is surrounded by dots that represent the valence electrons. Typically... |
form of carbon in which carbon atoms are arranged in hollow spheres | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | G | A fullerene (also called a Bucky ball) is a form of carbon in which carbon atoms are arranged in a hollow sphere resembling a soccer ball (see Figure 1.4). Each sphere contains 60 carbon atoms, and each carbon atom is bonded to three others by single covalent bonds. The bonds are relatively weak, so fullerenes can diss... |
All carbon polymers are made in labs or factories. | (A) true (B) false | B | Synthetic carbon polymers are produced in labs or factories. Plastics are common examples of synthetic carbon polymers. You are probably familiar with the plastic called polyethylene. All of the plastic items pictured in the Figure 1.3 are made of polyethylene. It consists of repeating monomers of ethylene (C2 H4 ). St... |
carbon compound found only in plants | (A) monomer (B) polymer (C) cellulose (D) diamond (E) methane (F) graphite (G) fullerene | C | The element carbon is the basis of all life on Earth. Biochemical compounds consist of chains of carbon atoms and just a few other elements. Like water, carbon is constantly recycled through the biotic and abiotic factors of ecosystems. The carbon cycle includes carbon in sedimentary rocks and fossil fuels under the gr... |
Graphite is used as a lubricant because it is slippery. | (A) true (B) false | A | Graphite is a form of crystalline carbon in which each carbon atom is covalently bonded to three other carbon atoms. The carbon atoms are arranged in layers, with strong bonds within each layer but only weak bonds between layers (see Figure 1.3). The weak bonds between layers allow the layers to slide over one another,... |
Each molecule of methane contains four atoms of carbon. | (A) true (B) false | B | A carbon atom can form covalent bonds with other carbon atoms or with the atoms of other elements. Carbon often forms bonds with hydrogen. Compounds that contain only carbon and hydrogen are called hydrocarbons. Methane (CH4 ), which is modeled in the Figure 1.2, is an example of a hydrocarbon. In methane, a single car... |
The chief component of cellulose is carbon. | (A) true (B) false | A | Cellulose is another complex carbohydrate that is a polymer of glucose. However, the glucose molecules are bonded together differently in cellulose than they are in starches. Cellulose molecules bundle together to form long, tough fibers (see Figure 9.18). Have you ever eaten raw celery? If you have, then you probably ... |
Carbon forms more compounds than any other element. | (A) true (B) false | A | Carbon is a very common ingredient of matter because it can combine with itself and with many other elements. It can form a great diversity of compounds, ranging in size from just a few atoms to thousands of atoms. There are millions of known carbon compounds, and carbon is the only element that can form so many differ... |
Carbon can form bonds with any other element except itself. | (A) true (B) false | B | Carbon can form single, double, or even triple bonds with other carbon atoms. In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons. Examples of compounds with these types of bonds are shown in Figure... |
The carbon compound with the formula CH4 is polyethylene. | (A) true (B) false | B | Synthetic carbon polymers are produced in labs or factories. Plastics are common examples of synthetic carbon polymers. You are probably familiar with the plastic called polyethylene. All of the plastic items pictured in the Figure 1.3 are made of polyethylene. It consists of repeating monomers of ethylene (C2 H4 ). St... |
In a triple bond, two atoms share three valence electrons. | (A) true (B) false | B | Carbon can form single, double, or even triple bonds with other carbon atoms. In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons. Examples of compounds with these types of bonds are shown in Figure... |
Plastics are examples of synthetic carbon polymers. | (A) true (B) false | A | Synthetic carbon polymers are produced in labs or factories. Plastics are common examples of synthetic carbon polymers. You are probably familiar with the plastic called polyethylene. All of the plastic items pictured in the Figure 1.3 are made of polyethylene. It consists of repeating monomers of ethylene (C2 H4 ). St... |
All forms of crystalline carbon have the same structure. | (A) true (B) false | B | Graphite is one of three forms of crystalline, or crystal-forming, carbon. Carbon also exists in an amorphous, or shapeless, form in substances such as coal and charcoal. Different forms of the same element are called allotropes. Besides graphite, the other allotropes of crystalline carbon are diamond and fullerenes. A... |
Carbon can combine only with hydrogen and oxygen. | (A) true (B) false | B | Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydro- carbons with four or more carbon atoms can have different shapes. Although they have the same chemical fo... |
Carbon forms ionic bonds with other nonmetals. | (A) true (B) false | B | Carbon is a nonmetal in group 14 of the periodic table. Like other group 14 compounds, carbon has four valence electrons. Valence electrons are the electrons in the outer energy level of an atom that are involved in chemical bonds. The valence electrons of carbon are shown in Figure 9.1. |
There are millions of known carbon compounds. | (A) true (B) false | A | Carbon is a very common ingredient of matter because it can combine with itself and with many other elements. It can form a great diversity of compounds, ranging in size from just a few atoms to thousands of atoms. There are millions of known carbon compounds, and carbon is the only element that can form so many differ... |
Which statement about hydrocarbons is true? | (A) They are the most complex type of carbon compounds (B) They are all gases at room temperature (C) They generally do not dissolve in water (D) none of the above | C | Hydrocarbons are compounds that contain only carbon and hydrogen. Hydrocarbons are the simplest type of carbon-based compounds. Nonetheless, they can vary greatly in size. The smallest hydrocarbons have just one or two carbon atoms, but large hydrocarbons may have hundreds. The size of hydrocarbon molecules influences ... |
Which statement about hydrocarbons is false? | (A) All of them are polar compounds (B) Most of them are obtained from fossil fuels (C) Some of them are solids at room temperature (D) They are the simplest type of carbon compounds | A | Hydrocarbons are compounds that contain only carbon and hydrogen. Hydrocarbons are the simplest type of carbon-based compounds, but they can vary greatly in size. The smallest hydrocarbons have just one or two carbon atoms. The largest hydrocarbons may have thousands of carbon atoms. Q: How are hydrocarbons involved in... |
The simplest hydrocarbons are | (A) unsaturated hydrocarbons (B) saturated hydrocarbons (C) aromatic hydrocarbons (D) alkenes and alkynes | B | Hydrocarbons are compounds that contain only carbon and hydrogen. Hydrocarbons are the simplest type of carbon-based compounds, but they can vary greatly in size. The smallest hydrocarbons have just one or two carbon atoms. The largest hydrocarbons may have thousands of carbon atoms. Q: How are hydrocarbons involved in... |
The last part of the name of a hydrocarbon compound indicates | (A) the number of bonds between carbon atoms (B) the number of carbon atoms per molecule (C) the shape of the hydrocarbon compound (D) none of the above | A | Saturated hydrocarbons are given the general name of alkanes. The name of specific alkanes always ends in -ane. The first part of the name indicates how many carbon atoms each molecule of the alkane has. The smallest alkane is methane. It has just one carbon atom. The next largest is ethane with two carbon atoms. The c... |
The first part of the name of a hydrocarbon indicates the number of | (A) bonds between carbon atoms (B) branches in the molecule (C) hydrogen atoms (D) carbon atoms | D | Saturated hydrocarbons are hydrocarbons that contain only single bonds between carbon atoms. They are the simplest class of hydrocarbons. They are called saturated because each carbon atom is bonded to as many hydrogen atoms as possible. In other words, the carbon atoms are saturated with hydrogen. You can see an examp... |
Hydrocarbons are used in floor wax because they | (A) resist scratches (B) tend to repel water (C) dissolve well in water (D) have high melting points | B | The size of hydrocarbon molecules influences their properties, including their melting and boiling points. As a result, some hydrocarbons are gases at room temperature, while others are liquids or solids. Hydrocarbons are generally nonpolar, which means that their molecules do not have oppositely charged sides. Therefo... |
Which of the following is an example of an unsaturated hydrocarbon? | (A) methene (B) pentane (C) propane (D) ethene | D | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. As a result, the carbon atoms are unable to bond with as many hydrogen atoms as they would if they were joined only by single bonds. This makes them unsaturated with hydrogen. Unsaturated hydrocarbons are classified on the basis o... |
Alkanes with more carbon atoms generally have | (A) higher boiling points (B) lower boiling points (C) higher melting points (D) two of the above | D | Saturated hydrocarbons are given the general name of alkanes. The name of specific alkanes always ends in -ane. The first part of the name indicates how many carbon atoms each molecule of the alkane has. The smallest alkane is methane. It has just one carbon atom. The next largest is ethane with two carbon atoms. The c... |
Aromatic hydrocarbons generally have | (A) a strong scent (B) rings of four carbon atoms (C) alternating double and triple bonds (D) all of the above | A | Unsaturated cyclic hydrocarbons are called aromatic hydrocarbons. Thats because they have a strong aroma, or scent. Their molecules consist of six carbon atoms in a ring shape, connected by alternating single and double bonds. Aromatic hydrocarbons may have a single ring or multiple rings joined together by bonds betwe... |
Dead organisms in ancient seas gradually formed deposits of | (A) coal (B) petroleum (C) natural gas (D) two of the above | D | Quick burial is essential because most decay and fragmentation occurs at the surface. Marine animals that die near a river delta may be rapidly buried by river sediments. A storm at sea may shift sediment on the ocean floor, covering a body and helping to preserve its skeletal remains (Figure 1.5). This fish was quickl... |
Hydrocarbon compounds that are burned for fuels include | (A) coal (B) propane (C) kerosene (D) all of the above | D | It is hard to overstate the importance of hydrocarbons to modern life. Hydrocarbons have even been called the driving force of western civilization. You saw some ways they are used in Figure 9.6. Several other ways are illustrated in Figure 9.15. Their most important use is as fuels. Gasoline, natural gas, fuel oil, di... |
Fossil fuels include | (A) wood (B) charcoal (C) petroleum (D) all of the above | C | Fossil fuels are mixtures of hydrocarbons that formed over millions of years from the remains of dead organisms. They include petroleum (commonly called oil), natural gas, and coal. Fossil fuels provide most of the energy used in the world today. They are burned in power plants to produce electrical energy, and they al... |
All hydrocarbons are small chemical compounds. | (A) true (B) false | B | Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydro- carbons with four or more carbon atoms can have different shapes. Although they have the same chemical fo... |
Hydrocarbons are generally nonpolar compounds. | (A) true (B) false | A | The size of hydrocarbon molecules influences their properties, including their melting and boiling points. As a result, some hydrocarbons are gases at room temperature, while others are liquids or solids. Hydrocarbons are generally nonpolar, which means that their molecules do not have oppositely charged sides. Therefo... |
Isomers of a given compound always have the same properties. | (A) true (B) false | B | Even compounds with the same number of carbon and hydrogen atoms can have different shapes. These compounds are called isomers. Look at the examples in Figure 9.9. The figure shows the structural formulas of butane and its isomer iso-butane. Both molecules have four carbon atoms and ten hydrogen atoms (C4 H10 ), but th... |
Hydrocarbons are compounds that contain only carbon and hydrogen. | (A) true (B) false | A | Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydro- carbons with four or more carbon atoms can have different shapes. Although they have the same chemical fo... |
Heptane is an unsaturated hydrocarbon. | (A) true (B) false | B | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. As a result, the carbon atoms are unable to bond with as many hydrogen atoms as they would if they were joined only by single bonds. This makes them unsaturated with hydrogen. Unsaturated hydrocarbons are classified on the basis o... |
The simplest hydrocarbons are the aromatic hydrocarbons. | (A) true (B) false | B | Unsaturated hydrocarbons called aromatic hydrocarbons are cyclic hydrocarbons that have double bonds. These compounds have six carbon atoms in a ring with alternating single and double bonds. The smallest aromatic hydrocarbon is benzene, which has just one ring. Its structural formula is shown in the Figure 1.2. Larger... |
Butane has branched-chain molecules. | (A) true (B) false | B | Even compounds with the same number of carbon and hydrogen atoms can have different shapes. These compounds are called isomers. Look at the examples in Figure 9.9. The figure shows the structural formulas of butane and its isomer iso-butane. Both molecules have four carbon atoms and ten hydrogen atoms (C4 H10 ), but th... |
The size of hydrocarbon molecules influences their properties. | (A) true (B) false | A | The size of hydrocarbon molecules influences their properties, including their melting and boiling points. As a result, some hydrocarbons are gases at room temperature, while others are liquids or solids. Hydrocarbons are generally nonpolar, which means that their molecules do not have oppositely charged sides. Therefo... |
Butane and iso-butane differ in their number of hydrogen atoms. | (A) true (B) false | B | Even compounds with the same number of carbon and hydrogen atoms can have different shapes. These compounds are called isomers. Look at the examples in Figure 9.9. The figure shows the structural formulas of butane and its isomer iso-butane. Both molecules have four carbon atoms and ten hydrogen atoms (C4 H10 ), but th... |
Any hydrocarbon ending in ane has only straight-chain molecules. | (A) true (B) false | B | Saturated hydrocarbons are hydrocarbons that contain only single bonds between carbon atoms. They are the simplest class of hydrocarbons. They are called saturated because each carbon atom is bonded to as many hydrogen atoms as possible. In other words, the carbon atoms are saturated with hydrogen. You can see an examp... |
Alkenes may form straight or branchedchains but not rings. | (A) true (B) false | B | Unsaturated hydrocarbons that contain at least one double bond are called alkenes. The name of a specific alkene always ends in ene, with a prefix indicating the number of carbon atoms. Figure 9.10 shows the structural formula for the smallest alkene. It has just two carbon atoms and is named ethene. Ethene is produced... |
Hydrocarbons are used to make synthetic fabrics such as polyester. | (A) true (B) false | A | It is hard to overstate the importance of hydrocarbons to modern life. Hydrocarbons have even been called the driving force of western civilization. You saw some ways they are used in the opening image. Several other ways are pictured in the Figure 1.1. The most important use of hydrocarbons is for fuel. Gasoline, natu... |
The physical properties of alkenes are generally similar to those of alkanes. | (A) true (B) false | A | Unsaturated hydrocarbons that contain at least one double bond are called alkenes. The name of a specific alkene always ends in ene, with a prefix indicating the number of carbon atoms. Figure 9.10 shows the structural formula for the smallest alkene. It has just two carbon atoms and is named ethene. Ethene is produced... |
Alkynes are relatively rare in nature. | (A) true (B) false | A | Unsaturated hydrocarbons that contain at least one triple bond are called alkynes. The name of specific alkynes always end in yne, with a prefix for the number of carbon atoms. Figure 9.12 shows the smallest alkyne, called ethyne, which has just two carbon atoms. Ethyne is also called acetylene. It is burned in acetyle... |
Fossil fuels formed over millions of years from dead organisms. | (A) true (B) false | A | Fossil fuels are made from plants and animals that lived hundreds of millions of years ago. The plants and animals died. Their remains settled onto the ground and at the bottom of the sea. Layer upon layer of organic material was laid down. Eventually, the layers were buried very deeply. They experienced intense heat a... |
Ring-shaped unsaturated hydrocarbons | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | F | Ring-shaped alkanes are called cycloalkanes. They usually contain just five or six carbon atoms because larger rings are not very stable. However, rings can join together to create larger molecules consisting of two or more rings. Compared with the straight- and branched-chain alkanes, cycloalkanes have higher boiling ... |
all compounds that consist only of carbon and hydrogen | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | D | Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydro- carbons with four or more carbon atoms can have different shapes. Although they have the same chemical fo... |
unsaturated hydrocarbons with at least one double bond | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | B | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. As a result, the carbon atoms are unable to bond with as many hydrogen atoms as they would if they were joined only by single bonds. This makes them unsaturated with hydrogen. Unsaturated hydrocarbons are classified on the basis o... |
ring-shaped saturated hydrocarbons | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | G | Saturated hydrocarbons are hydrocarbons that contain only single bonds between carbon atoms. They are the simplest class of hydrocarbons. They are called saturated because each carbon atom is bonded to as many hydrogen atoms as possible. In other words, the carbon atoms are saturated with hydrogen. You can see an examp... |
saturated hydrocarbons such as ethane | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | A | Saturated hydrocarbons are hydrocarbons that contain only single bonds between carbon atoms. They are the simplest class of hydrocarbons. They are called saturated because each carbon atom is bonded to as many hydrogen atoms as possible. In other words, the carbon atoms are saturated with hydrogen. You can see an examp... |
molecules with the same atoms but different shapes | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | E | Even compounds with the same number of carbon and hydrogen atoms can have different shapes. These compounds are called isomers. Look at the examples in Figure 9.9. The figure shows the structural formulas of butane and its isomer iso-butane. Both molecules have four carbon atoms and ten hydrogen atoms (C4 H10 ), but th... |
unsaturated hydrocarbons with at least one triple bond | (A) alkanes (B) alkenes (C) alkynes (D) hydrocarbons (E) isomers (F) aromatic hydrocarbons (G) cycloalkanes | C | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. As a result, the carbon atoms are unable to bond with as many hydrogen atoms as they would if they were joined only by single bonds. This makes them unsaturated with hydrogen. Unsaturated hydrocarbons are classified on the basis o... |
Classes of biochemical compounds include all of the following except | (A) lipids (B) proteins (C) phosphates (D) nucleic acids | C | Although there are millions of biochemical compounds, all of them can be grouped into just four main classes: carbohydrates, proteins, lipids, and nucleic acids. The classes are summarized in the Table 1.1. Class Carbohydrates Elements carbon hydrogen oxygen Examples sugars starches cellulose Proteins carbon hydrogen o... |
Living things use lipids for | (A) energy (B) enzymes (C) cell membranes (D) two of the above | D | Lipids are biochemical compounds such as fats and oils. Organisms use lipids to store energy. In addition to carbon and hydrogen, lipids contain oxygen. |
Functions of proteins include | (A) coding genetic information (B) storing energy in animals (C) regulating life processes (D) making up cell walls | C | Proteins are the most numerous and diverse biochemical compounds, and they have many different functions. Some of their functions include: making up tissues as components of muscle. speeding up biochemical reactions as enzymes. regulating life processes as hormones. helping to defend against infections as antibodies. c... |
Which statement about RNA is true? | (A) It has a double helix shape (B) It consists of two chains of nucleotides (C) It is needed for the synthesis of proteins (D) It contains the nitrogen base called thymine | C | RNA stands for ribonucleic acid. RNA is smaller than DNA. It can squeeze through pores in the membrane that encloses the nucleus. It copies instructions in DNA and carries them to a ribosome in the cytoplasm. Then it helps build the protein. RNA is not only smaller than DNA. It differs from DNA in other ways as well. I... |
A nucleotide consists of a | (A) phosphate group (B) nitrogen base (C) sugar (D) all of the above | D | Nucleotides are composed of three main parts: 1. a phosphate group. 2. a 5-carbon sugar (deoxyribose in DNA). 3. a nitrogen-containing base. The only difference between each nucleotide is the identity of the base. There are only four possible bases that make up each DNA nucleotide: adenine (A), guanine (G), thymine (T)... |
All biochemical compounds contain hydrogen. | (A) true (B) false | A | You can see from Table 2.1 that all biochemical compounds contain hydrogen and oxygen as well as carbon. They may also contain nitrogen, phosphorus, and/or sulfur. Almost all biochemical compounds are polymers. Polymers are large molecules that consist of many smaller, repeating molecules, called monomers. Most biochem... |
There are a total of 20 different biochemical compounds. | (A) true (B) false | B | Biochemical compounds make up the cells and tissues of living things. They are also involved in all life processes. Given their diversity of functions, its not surprising that there are millions of different biochemical compounds. Even so, all biochemical compounds can be grouped into just four main classes: carbohydra... |
Some nucleic acids are hormones that regulate life processes. | (A) true (B) false | B | Nucleic acids are long chains of nucleotides. Nucleotides are made of a sugar, a nitrogen-containing base, and a phosphate group. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are the two main nucleic acids. DNA is a double-stranded nucleic acid. DNA is the molecule that stores our genetic information ( Figure... |
Biochemical compounds are carbon-based compounds found in living things. | (A) true (B) false | A | Besides water, most of the compounds in living things are biochemical compounds. A biochemical compound is a carbon-based compound that is found in living organisms. Carbon is an element that has a tremendous ability to form large compounds. Each atom of carbon can form four chemical bonds with other atoms. A chemical ... |
The simplest sugar is named sucrose. | (A) true (B) false | B | Sugars are simple carbohydrates. Molecules of sugar have just a few carbon atoms. The simplest sugar is glucose (C6 H12 O6 ). Glucose is the sugar that the cells of living things use for energy. Plants and some other organisms make glucose in the process of photosynthesis. Living things that cannot make glucose obtain ... |
The main function of simple carbohydrates is to store energy in animals. | (A) true (B) false | B | Carbohydrates are sugars, or long chains of sugars. An important role of carbohydrates is to store energy. Glucose ( Figure 1.1) is an important simple sugar molecule with the chemical formula C6 H12 O6 . Simple sugars are known as monosaccharides. Carbohydrates also include long chains of connected sugar molecules. Th... |
Bread is a good source of starch in the diet. | (A) true (B) false | A | Starch is a large, complex carbohydrate made of thousands of glucose units (monomers) joined together. Starches are found in foods such as vegetables and grains. Starches are broken down by the body into sugars that provide energy. Breads and pasta are good sources of complex carbohydrates. Fiber is another type of lar... |
We need oils to help move food wastes through the digestive tract. | (A) true (B) false | B | Some substances in food cant be broken down into nutrients. They remain behind in the digestive system after the nutrients have been absorbed. Any substances in food that cant be digested pass out of the body as solid waste. This process is called elimination. |
The only biochemical compounds that contains sulfur are nucleic acids. | (A) true (B) false | B | Nucleic acids are one of four classes of biochemical compounds. (The other three classes are carbohydrates, proteins, and lipids.) Nucleic acids include RNA (ribonucleic acid) as well as DNA (deoxyribonucleic acid). Both types of nucleic acids contain the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus. Q: ... |
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