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gases used in halogen lights include | (A) neon (B) argon (C) mercury (D) two of the above | D | The halogen group is quite diverse. It includes elements that occur in three different states of matter at room temperature. Fluorine and chlorine are gases, bromine is a liquid, and iodine and astatine are solids. Halogens also vary in color, as you can see in the Figure 1.2. Fluorine and chlorine are green, bromine i... |
a vapor light produces light by fluorescence. | (A) true (B) false | B | A fluorescent light bulb produces visible light by fluorescence. Fluorescence occurs when a substance absorbs shorter-wavelength ultraviolet light and then gives off the energy as visible light. The compact fluorescent light bulb (CFL) in the Figure 1.2 contains mercury gas that gives off ultraviolet light when electri... |
forces that hold together particles within the atom include | (A) gravity (B) electromagnetic force (C) weak nuclear force (D) two of the above | D | When it comes to atomic particles, opposites attract. Negative electrons are attracted to positive protons. This force of attraction keeps the electrons moving about the nucleus. An analogy is the way planets orbit the sun. What about particles with the same charge, such as protons in the nucleus? They push apart, or r... |
the strong nuclear force is a force of attraction between quarks. | (A) true (B) false | A | The strong nuclear force is a force of attraction between fundamental particles called quarks, which have a type of charge called color charge. The strong nuclear force is transferred between quarks by fundamental force-carrying particles called gluons. Both protons and neutrons consist of quarks. The exchange of gluon... |
which statement about the strong nuclear force is false? | (A) It can overcome the electromagnetic force pushing protons apart (B) It works over very long distances (C) It is transferred by gluons (D) two of the above | B | The strong nuclear force is a force of attraction between fundamental particles called quarks, which have a type of charge called color charge. The strong nuclear force is transferred between quarks by fundamental force-carrying particles called gluons. Both protons and neutrons consist of quarks. The exchange of gluon... |
the weak nuclear force is transferred by w and z bosons. | (A) true (B) false | A | The weak nuclear force is transferred by the exchange of force-carrying fundamental particles called W and Z bosons. This force is also a very short-range force that works only within the nucleus of the atom. It is much weaker than the strong force or electromagnetic force that are also at work inside the atom. Unlike ... |
up quarks can change to down quarks. | (A) true (B) false | A | The weak nuclear force is transferred by the exchange of force-carrying fundamental particles called W and Z bosons. This force is also a very short-range force that works only within the nucleus of the atom. It is much weaker than the strong force or electromagnetic force that are also at work inside the atom. Unlike ... |
the nucleus contains | (A) protons (B) neutrons (C) electrons (D) two of the above | D | The nucleus is only found in eukaryotic cells. It contains most of the genetic material (the DNA) of the cell. The genetic material of the nucleus is like a set of instructions. These instructions tell the cell how to build molecules needed for the cell to function properly. That is, the DNA tells the cell how to build... |
outside of the nucleus, an atom is mostly empty space. | (A) true (B) false | A | The nucleus (plural, nuclei) is a positively charged region at the center of the atom. It consists of two types of subatomic particles packed tightly together. The particles are protons, which have a positive electric charge, and neutrons, which are neutral in electric charge. Outside of the nucleus, an atom is mostly ... |
the nucleus makes up about 1/100th of the total radius of an atom. | (A) true (B) false | B | The nucleus of the atom is extremely small. Its radius is only about 1/100,000 of the total radius of the atom. If an atom were the size of a football stadium, the nucleus would be about the size of a pea! Click image to the left or use the URL below. URL: Electrons have virtually no mass, but protons and neutrons hav... |
the nucleus has almost all of the mass of an atom. | (A) true (B) false | A | The nucleus of the atom is extremely small. Its radius is only about 1/100,000 of the total radius of the atom. If an atom were the size of a football stadium, the nucleus would be about the size of a pea! Click image to the left or use the URL below. URL: Electrons have virtually no mass, but protons and neutrons hav... |
what force holds together the nucleus? | (A) The force of attraction between positive and negative particles (B) The force of attraction between the nucleus and electrons (C) The strong nuclear force between protons and neutrons (D) The weak atomic force between neutrons and electrons | C | The strong nuclear force is a force of attraction between fundamental particles called quarks, which have a type of charge called color charge. The strong nuclear force is transferred between quarks by fundamental force-carrying particles called gluons. Both protons and neutrons consist of quarks. The exchange of gluon... |
there is an electric force of repulsion between neutrons and protons. | (A) true (B) false | B | Particles with opposite electric charges attract each other. This explains why negative electrons orbit the positive nucleus. Particles with the same electric charge repel each other. This means that the positive protons in the nucleus push apart from one another. So why doesnt the nucleus fly apart? An even stronger f... |
all atoms of a given element have the same number of protons. | (A) true (B) false | A | The number of protons per atom is always the same for a given element. However, the number of neutrons may vary, and the number of electrons can change. |
atoms of different elements always have different numbers of protons. | (A) true (B) false | A | The number of protons per atom is always the same for a given element. However, the number of neutrons may vary, and the number of electrons can change. |
which statement about the mass of subatomic particles is false? | (A) A proton has a mass of 1 amu (B) A neutron has slightly more mass than a proton (C) An electron has slightly less mass than a proton (D) none of the above | C | Based on their knowledge of subatomic particles, scientists have developed a theory called the standard model to explain all the matter in the universe and how it is held together. The model includes only the fundamental particles in the Table 1.2. No other particles are needed to explain all kinds of matter. According... |
a carbon atom has six protons and six neutrons. what is its atomic number? | (A) 6 (B) 12 (C) 36 (D) none of the above | A | Find carbon in the Figure 1.1, and youll see that its atomic number is 6. This means that all carbon atoms have 6 protons per nucleus. Almost all carbon atoms also have 6 neutrons per nucleus. These carbon atoms are called carbon-12, where 12 is the number of protons (6) plus neutrons (6). This gives carbon-12 nuclei a... |
what is the mass number of the carbon atom in question 8? | (A) 6 (B) 12 (C) 18 (D) 72 | B | For most other elements, isotopes are named for their mass number. For example, carbon atoms with the usual 6 neutrons have a mass number of 12 (6 protons + 6 neutrons = 12), so they are called carbon-12. Carbon atoms with 7 neutrons have an atomic mass of 13 (6 protons + 7 neutrons = 13). These atoms are the isotope c... |
which of the following is the general form of a chemical equation? | (A) Reactants = Products (B) Products + Reactants = 100% (C) Products β Reactants (D) Reactants β Products | D | A chemical equation is a shorthand way to sum up what occurs in a chemical reaction. The general form of a chemical equation is: Reactants Products The reactants in a chemical equation are the substances that begin the reaction, and the products are the substances that are produced in the reaction. The reactants are a... |
which of the following equations is balanced? | (A) H2 + O2 β H2O (B) 2H2 + O2 β 2H2O (C) H2 + 2O2 β 2H2O (D) 2H2 + O2 β H2O | B | All chemical equations, like equations in math, must balance. This means that there must be the same number of each type of atom on both sides of the arrow. Thats because matter is always conserved in a chemical reaction. This is the law of conservation of mass. Look at the equation above for the reaction between carbo... |
numbers called subscripts are used to balance chemical equations. | (A) true (B) false | B | Coefficients are used to balance chemical equations. A coefficient is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2H2 . A coefficient of 1 usually isnt written. Co... |
which of the following rules should you follow to balance chemical equations? | (A) Change only the subscripts (B) Use the smallest possible subscripts (C) Add coefficients as needed (D) two of the above | C | All chemical equations, like equations in math, must balance. This means that there must be the same number of each type of atom on both sides of the arrow. Thats because matter is always conserved in a chemical reaction. This is the law of conservation of mass. Look at the equation above for the reaction between carbo... |
which coefficient will balance the following equation? zn + hcl zncl2 + h2 | (A) 2 (B) 3 (C) 4 (D) none of the above | A | Coefficients are used to balance chemical equations. A coefficient is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2H2 . A coefficient of 1 usually isnt written. Co... |
which particle is emitted from a nucleus when it undergoes beta-minus decay? | (A) electron (B) positron (C) anti-electron (D) proton | A | Beta decay occurs when an unstable nucleus emits a beta particle and energy. A beta particle is either an electron or a positron. An electron is a negatively charged particle, and a positron is a positively charged electron (or anti- electron). When the beta particle is an electron, the decay is called beta-minus decay... |
beta-positive decay begins with a proton. | (A) true (B) false | A | Beta decay occurs when an unstable nucleus emits a beta particle and energy. A beta particle is either an electron or a positron. An electron is a negatively charged particle, and a positron is a positively charged electron (or anti- electron). When the beta particle is an electron, the decay is called beta-minus decay... |
in the following symbol for a beta-minus particle, what does the superscript represent? | (A) charge (B) mass (C) energy (D) none of the above | B | Radioactive nuclei and particles are represented by nuclear symbols.. For example, a beta-minus particle (electron) is represented by the symbol 01 e. The subscript -1 represents the particles charge, and the superscript 0 shows that the particle has virtually no mass (no protons or neutrons). Another example is the ra... |
beta particles can travel only a few centimeters through the air. | (A) true (B) false | B | Beta particles can travel about a meter through air. They can pass through a sheet of paper or a layer of cloth but not through a sheet of aluminum or a few centimeters of wood. They can also penetrate the skin and damage underlying tissues. They are even more harmful if they are ingested or inhaled. |
beta-positive decay results in a nucleus with one less proton. | (A) true (B) false | A | Beta decay occurs when an unstable nucleus emits a beta particle and energy. A beta particle is either an electron or a positron. An electron is a negatively charged particle, and a positron is a positively charged electron (or anti- electron). When the beta particle is an electron, the decay is called beta-minus decay... |
there are only about 100 different biochemical compounds. | (A) true (B) false | B | All known matter can be divided into a little more than 100 different substances called elements. |
the similarity in biochemical compounds between living things provides some of the best evidence for evolution. | (A) true (B) false | A | Scientists have learned a lot about evolution by comparing living organisms. They have compared body parts, embryos, and molecules such as DNA and proteins. |
functions of carbohydrates include | (A) storing energy in plants (B) storing energy in animals (C) making up cell walls in plants (D) two of the above | D | Carbohydrates are biochemical compounds that include sugars, starches, and cellulose. They contain oxygen in addition to carbon and hydrogen. Organisms use carbohydrates mainly for energy. |
functions of nucleic acids include | (A) storing genetic information in cells (B) speeding up biochemical reactions (C) regulating life processes (D) all of the above | A | Nucleic acids are biochemical molecules that contain oxygen, nitrogen, and phosphorus in addition to carbon and hydrogen. There are two main types of nucleic acids. They are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). |
elements found in proteins but not in other biochemical compounds include | (A) sulfur (B) nitrogen (C) phosphorus (D) two of the above | A | Proteins are biochemical compounds that contain oxygen, nitrogen, and sulfur in addition to carbon and hydrogen. Protein molecules consist of one or more chains of small molecules called amino acids. |
almost all biochemical compounds are polymers. | (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... |
catabolic reactions are chemical reactions in living things that | (A) release energy (B) are endothermic (C) break bonds (D) two of the above | D | Biochemical reactions of metabolism can be divided into two general categories: catabolic reactions and anabolic reactions. Catabolic reactions involve breaking bonds. Larger molecules are broken down to smaller ones. For example, complex carbohydrates are broken down to simple sugars. Catabolic reactions release energ... |
anabolic reactions are chemical reactions in living things that | (A) form larger molecules (B) are exothermic (C) release energy (D) two of the above | A | The sum of all of an organisms biochemical reactions is called metabolism. Biochemical reactions of metabolism can be divided into two general categories: catabolic reactions and anabolic reactions. You can watch an animation showing how the two categories of reactions are related at this link: Anabolic reactions invol... |
the reactants of photosynthesis are oxygen and water. | (A) true (B) false | B | Some of the most important biochemical reactions are the reactions involved in photosynthesis and cellular respira- tion. Together, these two processes provide energy to almost all of Earths organisms. The two processes are closely related, as you can see in the Figure 1.1. In photosynthesis, light energy from the sun ... |
photosynthesis is an anabolic reaction. | (A) true (B) false | A | Some of the most important biochemical reactions are the reactions involved in photosynthesis and cellular respira- tion. Photosynthesis is the process in which producers capture light energy from the sun and use it to make glucose. This involves anabolic reactions. Cellular respiration is the process in which energy i... |
cellular respiration is a catabolic reaction. | (A) true (B) false | A | The reactions of cellular respiration are catabolic reactions. In catabolic reactions, bonds are broken in larger molecules and energy is released. In cellular respiration, bonds are broken in glucose, and this releases the chemical energy that was stored in the glucose bonds. Some of this energy is converted to heat. ... |
electrons with the most energy are located closest to the nucleus of the atom. | (A) true (B) false | B | Electrons are located at fixed distances from the nucleus, called energy levels. You can see the first three energy levels in the Figure 1.3. The diagram also shows the maximum possible number of electrons at each energy level. Electrons at lower energy levels, which are closer to the nucleus, have less energy. At the ... |
bohr hypothesized that if an electron gained just the right amount of energy, it would | (A) jump to the next higher energy level (B) drop down to the next lower energy level (C) move halfway to the next higher energy level (D) crash into the nucleus of the atom | A | As a young man, Bohr worked in Rutherfords lab in England. Because Rutherfords model was weak on the position of the electrons, Bohr focused on them. He hypothesized that electrons can move around the nucleus only at fixed distances from the nucleus based on the amount of energy they have. He called these fixed distanc... |
the idea of the quantum was first introduced by | (A) Bohr (B) Planck (C) Thomson (D) Rutherford | B | Bohrs model of the atom is actually a combination of two different ideas: Rutherfords atomic model of electrons orbiting the nucleus and German scientist Max Plancks idea of a quantum, which Planck published in 1901. A quantum (plural, quanta) is the minimum amount of energy that can be absorbed or released by matter. ... |
energy levels around the atomic nucleus correspond to quantum increases in energy. | (A) true (B) false | A | Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center. Energy levels are a little like the steps of a staircase. You can stand on one step o... |
which type(s) of chemical bonds may be polar bonds? | (A) ionic bonds (B) metallic bonds (C) covalent bonds (D) two of the above | C | In some covalent bonds, electrons are not shared equally between the two atoms. These are called polar bonds. Figure 7.9 shows this for water. The oxygen atom attracts the shared electrons more strongly because its nucleus has more positively charged protons. As a result, the oxygen atom becomes slightly negative in ch... |
which of the following molecules has (have) polar bonds? | (A) water (B) carbon dioxide (C) formaldehyde (D) all of the above | D | Polar compounds, such as water, are compounds that have a partial negative charge on one side of each molecule and a partial positive charge on the other side. All polar compounds contain polar bonds (although not all compounds that contain polar bonds are polar.) In a polar bond, two atoms share electrons unequally. O... |
all molecules with polar bonds are polar molecules. | (A) true (B) false | B | Polar compounds, such as water, are compounds that have a partial negative charge on one side of each molecule and a partial positive charge on the other side. All polar compounds contain polar bonds (although not all compounds that contain polar bonds are polar.) In a polar bond, two atoms share electrons unequally. O... |
the oxygen end of a water molecule is positively charged. | (A) true (B) false | B | Water is simply two atoms of hydrogen and one atom of oxygen bonded together (Figure 1.1). The hydrogen ions are on one side of the oxygen ion, making water a polar molecule. This means that one side, the side with the hydrogen ions, has a slightly positive electrical charge. The other side, the side without the hydrog... |
a fluid exerts pressure only in an upward direction. | (A) true (B) false | B | Buoyancy is the ability of a fluid to exert an upward force on any object placed in the fluid. This upward force is called buoyant force. |
fluid pressure is greater at greater depth. | (A) true (B) false | A | Two factors influence the pressure of fluids. They are the depth of the fluid and its density. A fluid exerts more pressure at greater depths. Deeper in a fluid, all of the fluid above it results in more weight pressing down. This causes greater pressure the deeper you go. Denser fluids such as water exert more pressur... |
the fluid below an object exerts greater force on it than the fluid above the object. | (A) true (B) false | A | What explains buoyant force? Recall from the earlier lesson "Pressure of Fluids" that a fluid exerts pressure in all directions but the pressure is greater at greater depth. Therefore, the fluid below an object exerts greater force on the object than the fluid above the object. This is illustrated in Figure 15.12. Buoy... |
an object floats in a fluid when the | (A) buoyant force acting on the object is greater than the objectβs weight (B) objectβs weight is greater than the buoyant force acting on the object (C) objectβs weight is the same as buoyant force acting on the object (D) buoyant force acts only under and not above the object | A | Objects such as ships may float in a fluid like water because of buoyant force. This is an upward force that a fluid exerts on any object that is placed in it. Archimedes discovered that the buoyant force acting on an object equals the weight of the fluid displaced by the object. This is known as Archimedes law (or Arc... |
a denser substance will | (A) float on a less dense fluid (B) sink in a less dense fluid (C) become less dense in a less dense fluid (D) become more dense in a less dense fluid | B | You are going to visit a friend. You fill one backpack with books so you can study later. You stuff your pillow into another backpack that is the same size. Which backpack will be easier to carry? Even though the backpacks are the same size, the bag that contains your books is going to be much heavier. It has a greater... |
any change in an objects motion is called velocity. | (A) true (B) false | B | In science, motion is defined as a change in position. An objects position is its location. Besides the wings of the hummingbird in the opening image, you can see other examples of motion in the Figure 1.1. In each case, the position of something is changing. Q: In each picture in the Figure 1.1, what is moving and how... |
the greater the net force acting on an object, the greater its acceleration will be. | (A) true (B) false | A | A change in an objects motionsuch as Xander speeding up on his scooteris called acceleration. Acceleration occurs whenever an object is acted upon by an unbalanced force. The greater the net force acting on the object, the greater its acceleration will be, but the mass of the object also affects its acceleration. The s... |
for a given net force, an object will accelerate less if it has a greater | (A) mass (B) volume (C) speed (D) none of the above | A | Newtons second law shows that there is a direct relationship between force and acceleration. The greater the force that is applied to an object of a given mass, the more the object will accelerate. For example, doubling the force on the object doubles its acceleration. The relationship between mass and acceleration, on... |
one newton is the force needed to cause a | (A) 1-kg object to accelerate at 1 m/s2 (B) 1-g object to accelerate at 1 cm/s2 (C) 1-kg object to accelerate at 1 km/s2 (D) none of the above | A | The SI unit of force is the newton (N). One newton is the amount of force that causes a mass of 1 kilogram to accelerate at 1 m/s2 . Thus, the newton can also be expressed as kgm/s2 . The newton was named for the scientist Sir Isaac Newton, who is famous for his law of gravity. Youll learn more about Sir Isaac Newton l... |
the si unit for acceleration is | (A) cm/s2 (B) m/s2 (C) km/s2 (D) none of the above | B | The SI unit of force is the newton (N). One newton is the amount of force that causes a mass of 1 kilogram to accelerate at 1 m/s2 . Thus, the newton can also be expressed as kgm/s2 . The newton was named for the scientist Sir Isaac Newton, who is famous for his law of gravity. Youll learn more about Sir Isaac Newton l... |
which equation is used to calculate average acceleration when only speed is changing? | (A) average acceleration = Ξv/Ξt (B) average acceleration = Ξt/Ξv (C) average acceleration = Ξd/Ξt (D) average acceleration = v/Ξt | A | Calculating acceleration is complicated if both speed and direction are changing or if you want to know acceleration at any given instant in time. However, its relatively easy to calculate average acceleration over a period of time when only speed is changing. Then acceleration is the change in velocity (represented by... |
it is easier to calculate acceleration for any given moment of time than to calculate average acceleration for a period of time. | (A) true (B) false | B | Calculating acceleration is complicated if both speed and direction are changing or if you want to know acceleration at any given instant in time. However, its relatively easy to calculate average acceleration over a period of time when only speed is changing. Then acceleration is the change in velocity (represented by... |
the si unit for acceleration is | (A) m/s (B) m/s2 (C) m/s2 (D) none of the above | C | The SI unit of force is the newton (N). One newton is the amount of force that causes a mass of 1 kilogram to accelerate at 1 m/s2 . Thus, the newton can also be expressed as kgm/s2 . The newton was named for the scientist Sir Isaac Newton, who is famous for his law of gravity. Youll learn more about Sir Isaac Newton l... |
which of the following units could represent acceleration? | (A) cm/s (B) km/h2 (C) m/h (D) cm/h | B | This equation for acceleration can be used to calculate the acceleration of an object that is acted on by a net force. For example, Xander and his scooter have a total mass of 50 kilograms. Assume that the net force acting on Xander and the scooter is 25 Newtons. What is his acceleration? Substitute the relevant values... |
when calculating work, force is measured in | (A) joules (B) Newtons (C) foot-pounds (D) none of the above | B | The equation for work can be used to calculate work if force and distance are known. To use the equation, force is expressed in Newtons (N), and distance is expressed in meters (m). For example, assume that Clarissa uses 100 Newtons of force to push the mower and that she pushes it for a total of 200 meters as she cuts... |
one joule equals the amount of work that is done when 1 n of force moves an object over a distance of | (A) 1 cm (B) 1 m (C) 1 km (D) none of the above | B | Because energy is the ability to do work, it is expressed in the same unit that is used for work. The SI unit for both work and energy is the joule (J), or Newton meter (N m). One joule is the amount of energy needed to apply a force of 1 Newton over a distance of 1 meter. For example, suppose the boy in the Figure 1... |
you can calculate force from work and distance with the equation | (A) Force = Work x Distance (B) Force = Work/Distance (C) Force = Distance/Work (D) Force = Work + Distance | B | Work is the use of force to move an object. It is directly related to both the force applied to the object and the distance the object moves. Work can be calculated with this equation: Work = Force x Distance. |
you can calculate distance from work and force with the equation | (A) Distance = Work x Force (B) Distance = Work/Force (C) Distance = Force/Work (D) Distance = Work + Force | B | Work is the use of force to move an object. It is directly related to both the force applied to the object and the distance the object moves. Work can be calculated with this equation: Work = Force x Distance. |
carbohydrates consist of atoms of | (A) carbon (B) hydrogen (C) oxygen (D) all of the above | D | Carbohydrates are one of four classes of biochemical compounds. The other three classes are proteins, lipids, and nucleic acids. In addition to cellulose, carbohydrates include sugars and starches. Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for energy. Q... |
plants stores extra glucose as starches. | (A) true (B) false | A | Starches are complex carbohydrates. They are polymers of glucose. They consist of hundreds of glucose monomers bonded together. Plants make starch to store extra sugars. Consumers get starch from plants. Common sources of starch in the human diet are pictured in Figure 9.17. Our digestive system breaks down starch to s... |
cellulose is a polymer of starch. | (A) true (B) false | B | Cellulose is another complex carbohydrate that is a polymer of glucose. However, glucose molecules are bonded together differently in cellulose than they are in starches. Cellulose molecules bundle together to form long, tough fibers, as you can see in the Figure 1.3. Have you ever eaten raw celery? If you have, then y... |
about half of all known compounds contain carbon. | (A) true (B) false | B | 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... |
how many chemical 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... |
methane is an example of a hydrocarbon. | (A) true (B) false | A | 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... |
carbon forms triple bonds with other carbon atoms in the compound named | (A) ethane (B) ethene (C) ethyne (D) two of the above | C | 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... |
when two carbon atoms form triple bonds, how many electrons do they share? | (A) 3 (B) 4 (C) 5 (D) 6 | 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... |
carbon can form 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... |
examples of naturally occurring carbon polymers include | (A) cellulose (B) rubber (C) plastic (D) two of the above | D | Many polymers of carbon occur naturally. Two examples are rubber and cellulose. Rubber is a natural polymer of the monomer named isoprene (C5 H8 ). This polymer comes from rubber trees, which grow in tropical areas. Structural formulas for rubber and isoprene are shown in the Figure 1.2. Note that just a small section ... |
rubber consists of the monomer named ethylene. | (A) true (B) false | B | Many polymers of carbon occur naturally. Two examples are rubber and cellulose. Rubber is a natural polymer of the monomer named isoprene (C5 H8 ). This polymer comes from rubber trees, which grow in tropical areas. Structural formulas for rubber and isoprene are shown in the Figure 1.2. Note that just a small section ... |
any given polymer consists of just one type of monomer. | (A) true (B) false | 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... |
a catalyst is a reactant in the reaction it catalyzes. | (A) true (B) false | B | A catalyst is a substance that increases the rate of a chemical reaction. The presence of a catalyst is one of several factors that influence the rate of chemical reactions. (Other factors include the temperature, concentration, and surface area of reactants.) A catalyst isnt a reactant in the chemical reaction it spee... |
a catalyst is used up in the reaction it catalyzes. | (A) true (B) false | B | Some reactions need extra help to occur quickly. They need another substance, called a catalyst. A catalyst is a substance that increases the rate of a chemical reaction but is not changed or used up in the reaction. The catalyst can go on to catalyze many more reactions. Catalysts are not reactants, but they help reac... |
the compound that speeds up the breakdown of starch to sugar in your mouth is | (A) an enzyme (B) called amylase (C) also found in your small intestine (D) all of the above | D | The mouth is the first digestive organ that food enters. The sight, smell, or taste of food stimulates the release of saliva and digestive enzymes by salivary glands inside the mouth. Saliva wets the food, which makes it easier to break up and swallow. The enzyme amylase in saliva begins the chemical digestion of starc... |
more than 1000 different enzymes are necessary for human life. | (A) true (B) false | A | More than 1000 different enzymes are necessary for human life. Many enzymes are needed for the digestion of food. Two examples are amylase and pepsin. Both are described in the Figure 1.2. |
the presence or absence of a catalyst is the only factor that affects the rate of a chemical reaction. | (A) true (B) false | B | 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. |
organisms that make glucose are called autotrophs. | (A) true (B) false | A | Types of organisms that make glucose by photosynthesis are pictured in Figure 4.7. They include plants, plant-like protists such as algae, and some kinds of bacteria. Living things that make glucose are called autotrophs ("self feeders"). All other living things obtain glucose by eating autotrophs (or organisms that ea... |
cellular respiration takes place only in the cells of heterotrophs. | (A) true (B) false | B | Cellular respiration takes place in the cells of all organisms. It occurs in autotrophs such as plants as well as heterotrophs such as animals. Cellular respiration begins in the cytoplasm of cells. It is completed in mitochondria. The mitochondrion is a membrane-enclosed organelle in the cytoplasm. Its sometimes calle... |
the chemical reactions of cellular respiration are anabolic reactions. | (A) true (B) false | B | Some of the most important biochemical reactions are the reactions involved in photosynthesis and cellular respira- tion. Photosynthesis is the process in which producers capture light energy from the sun and use it to make glucose. This involves anabolic reactions. Cellular respiration is the process in which energy i... |
which compound directly powers biochemical reactions in cells? | (A) glucose (B) carbon dioxide (C) adenosine triphosphate (D) none of the above | C | Glucose is an example of a biochemical compound. The prefix bio- comes from the Greek word that means life. A biochemical compound is any carbon-based compound that is found in living things. Biochemical compounds make up the cells and tissues of living things. They are also involved in all life processes, including ma... |
during cellular respiration, chemical energy stored in glucose changes to | (A) heat (B) light (C) chemical energy in ATP (D) two of the above | D | Specifically, during cellular respiration, the energy stored in glucose is transferred to ATP ( Figure 1.1). ATP, or adenosine triphosphate, is chemical energy the cell can use. It is the molecule that provides energy for your cells to perform work, such as moving your muscles as you walk down the street. But cellular ... |
valence electrons are the basis of all chemical bonds. | (A) true (B) false | A | A chemical bond is a force of attraction between atoms or ions. Bonds form when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom that may be involved in chemical interactions. Valence electrons are the basis of all chemical bonds. Q: Why do you think th... |
in covalent bonds, atoms | (A) share electrons (B) transfer electrons (C) lose or gain electrons (D) two of the above | A | A covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. The shared electrons are attracted to the nuclei of both atoms. This forms a molecule consisting of two or more atoms. Covalent bonds form only between atoms of nonmetals. |
an example of a compound that contains ionic bonds is water. | (A) true (B) false | B | There are two basic types of compounds that differ in the nature of the bonds that hold their atoms or ions together. They are covalent and ionic compounds. Both types are described below. Click image to the left or use the URL below. URL: Covalent compounds consist of atoms that are held together by covalent bonds. T... |
a metallic bond is a bond between a positively charged metal ion and | (A) a negatively charged halogen ion (B) a negatively charged nonmetal ion (C) the valence electrons of several metal ions (D) the valence electrons of a halogen ion | C | A metallic bond is the force of attraction between a positive metal ion and the valence electrons it shares with other ions of the metal. The positive ions form a lattice-like structure. You can see an example in Figure 7.13. (For an animated version, go to the URL below.) The ions are held together in the lattice by b... |
metallic bonds form a lattice-like structure. | (A) true (B) false | A | Metallic bonds are forces of attraction between positive metal ions and the valence electrons that are constantly moving around them (see the Figure 1.1). The valence electrons include their own and those of other, nearby ions of the same metal. The valence electrons of metals move freely in this way because metals hav... |
metals can be involved in | (A) covalent bonds (B) metallic bonds (C) ionic bonds (D) two of the above | D | We rely on metals, such as aluminum, copper, iron, and gold. Look around the room. How many objects have metal parts? Metals are used in the tiny parts inside your computer, in the wires of anything that uses electricity, and to make the structure of a large building, such as the one shown in the Figure 3.23. |
the substances that form in a chemical reaction are completely different from the substances that start the reaction. | (A) true (B) false | A | A chemical reaction is a process in which some substances change into different substances. Substances that start a chemical reaction are called reactants. Substances that are produced in the reaction are called products. Reactants and products can be elements or compounds. A chemical reaction can be represented by thi... |
a chemical equation is balanced when | (A) the reactants are the same as the products (B) the same atoms and molecules appear on each side of the equation (C) the same number of each type of atom appears on both sides of the arrow (D) none of the above | C | All chemical equations, like equations in math, must balance. This means that there must be the same number of each type of atom on both sides of the arrow. Thats because matter is always conserved in a chemical reaction. This is the law of conservation of mass. Look at the equation above for the reaction between carbo... |
which of the following chemical equations is balanced? | (A) 3Fe + 3O2 β 3Fe2O3 (B) 2Fe + O2 β Fe2O3 (C) 4Fe + 2O2 β 3Fe2O3 (D) 4Fe + 3O2 β 2Fe2O3 | D | All chemical equations, like equations in math, must balance. This means that there must be the same number of each type of atom on both sides of the arrow. Thats because matter is always conserved in a chemical reaction. This is the law of conservation of mass. Look at the equation above for the reaction between carbo... |
a given chemical compound always has exactly the same ratio of elements. | (A) true (B) false | A | All chemical equations, like equations in math, must balance. This means that there must be the same number of each type of atom on both sides of the arrow. Thats because matter is always conserved in a chemical reaction. This is the law of conservation of mass. Look at the equation above for the reaction between carbo... |
when there is just one atom of an element in a molecule, this atom is represented by the | (A) subscript 1 (B) subscript 0 (C) absence of a subscript (D) none of the above | C | The smallest particle of an element that still has the properties of that element is an atom. Atoms are extremely tiny. They can be observed only with an electron microscope. They are commonly represented by models, like the one Figure 2.6. An atom has a central nucleus that is positive in charge. The nucleus is surrou... |
in the formula for an ionic compound, the negative ion is always written first. | (A) true (B) false | B | Ionic compounds are named for their positive and negative ions. The name of the positive ion always comes first, followed by the name of the negative ion. For example, positive sodium ions and negative chloride ions form the compound named sodium chloride. Similarly, positive calcium ions and negative chloride ions for... |
correct rules for writing the chemical formulas of covalent compounds include which of the following? | (A) The element that is farther to the left in the periodic table is written first (B) The element that is farther to the right in the periodic table is written first (C) If both elements are in the same group of the periodic table (D) the one with the lower period number is written first (E) d two of the above | A | To name simple covalent compounds, follow these rules: Start with the name of the element closer to the left side of the periodic table. Follow this with the name of element closer to the right of the periodic table. Give this second name the suffix -ide. Use prefixes to represent the numbers of the different atoms in ... |
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