Test 1

In the figure below, which portion represents the atomic mass? 12 C 6

12 Explanation: 12 represents the atomic mass which is the number of protons plus neutrons.

The Age of theology took place during the

200-1200 A.D. Explanation: The period of 200-1200 A.D. is referred to as the Age of theology, scientific explanations for phenomena were not considered.

What are the number of protons, neutrons, and electrons for the −2 anion from the 17O isotope of oxygen? (The atomic number of oxygen is 8.)

8p+; 9n; 10e− Explanation: A neutral oxygen atom has eight protons, eight neutrons, and eight electrons. The oxygen-17 isotope still has eight protons, and must have nine neutrons (for a mass number of 17). To have a −2 charge oxygen must have two electrons in addition to the eight that are present in a neutral oxygen atom.

In water, spheres of hydration form around

A and C Explanation: Spheres of hydration form around hydrophilic molecules. Polar molecules are hydrophilic because their partially charged atoms are attracted to the partial charges of oxygen and hydrogen. Ions are generally hydrophilic because they are charged and attracted to the partial charges of oxygen and hydrogen in water molecules.

polar covalent bond

A bond intermediate between a covalent bond and an ionic bond; a covalent bond with uneven electron density.

ionic bond

A chemical bond formed when one atom completely transfers one or more electrons to another atom.

electronegativity

An index of the ability of an atom to attract electrons.

(True or False) Carbon has 6 electrons

False

(True or False) More than two electrons can be in a particular (meaning singular) orbital.

False Explanation: A single orbital holds a maximum of two electrons. More than one orbital may be found in an electron shell; thus, more than two electrons may be in an electron shell.

True or false? Fats do not mix with water because they are polar.

false

Bacon, Roger

(1214-1294) A philosopher and proponent of experimental science who urged people to reject religious dogma and "look at the world".

Thomas Aquinas

(1224-1274) Theologian. Made the distinction between natural truth and revealed truth.

Bacon, Francis

(1561-1626) A philosopher who advocated experimentalism as a way to verify and rigorously test all things.

Galilei, Galileo

(1564-1642) A mathematician that advocated the view of Copernicus that the Earth is round and revolves around the sun.

Usher, James

(1581-1656) Archbishop who declared, based on biblical interpretation, that the Earth was created in 4004 B.C.

Ray, John

(1627-1705) Naturalist who noted that fossils were the remnants of once living organisms.

Cuvier, Georges

(1769-1832) The French anatomist who developed the science of paleontology. He also proposed the theory of catastrophism to explain boundaries in the fossil record.

Darwin, Charles

(1809-1882) The English naturalist who developed the theory of evolution by natural selection based on observations made on a trip around the world on the H.M.S. Beagle. The theory was published in a joint paper with A.R. Wallace, who independently developed the theory, in 1858. Darwin published the book On the Origin of Species by Means of Natural Selection: or the Preservation of Favoured Races in the Struggle for Life in 1859, describing the evidence for the theory and popularizing it. Darwin published some 16 other books.

Aristotle

(384-322 BC) A Greek philosopher who identified four elements: earth, air, fire, and water.

Albertus Magnus

(c. 1200-1280) Dominican Archbishop and philosopher, known as a teacher to St. Thomas Aquinas.

Considering the valence electron configuration of magnesium (atomic number 12), which is the most likely charge produced by the ionization of magnesium?

+2 Explanation:Atoms tend to gain or lose electrons to achieve a stable electron configuration in which the valence shells have their full complement of electrons. The easiest way to determine this configuration is to locate the noble gas closest to the element of interest on the periodic table, and calculate the number of electrons the element would have to gain or lose to achieve the same number of electrons as the noble gas. In the case of magnesium, the nearest noble gas is neon. Neon has two fewer electrons than magnesium. Loss of electrons results in a positive charge of the same magnitude as the number of electrons lost, in this case +2.

An electron is

A negatively charged subatomic particle.

scientific method

A systematic approach to answering a question. The steps include: making observations forming a hypothesis designing an experiment gathering data drawing a conclusion

hydrogen bond

A type of bond formed when a partially positive hydrogen atom is attracted to a partially negative atom from another molecule.

Covalent bond

A type of chemical bond in which electrons are shared between atoms.

ion

An atom or group of atoms with a net positive or negative charge.

In the mid-1600s, __________________ declared that the Earth was created in 4004 B.C.

Archbishop James Usher Explanation: The Archbishop James Usher declared that the Earth was created in 4004 B.C

Which of the following is not a reason that atoms bond?

Atoms bond to overcome their electronegativity. *Electrons tend to travel in pairs. * Atoms are influenced by electrostatitcs *Atoms tend to form completely filled outer shells. Explanation: Electronegativity is the ability to gain or hold electrons; it is the difference in the electronegativities that determines what type of bond atoms form. Atoms do not overcome their electronegativity to bond; the bond is driven by the electronegativity.

Ionization is caused by the gain or loss of these atomic particles.

Electrons Explanation:Gain or loss of electrons results in the creation of ions because of the resulting imbalance in the number of protons and electrons. If an atom gains electrons, a negative charge will result. If the atom loses electrons, a positive charge will result. Atoms tend to gain or lose electrons to give them the same number of electrons as the nearest noble gas in the periodic table.

Who championed the experimental method during the late 16th and early 17th centuries?

Francis Bacon Explanation: Francis Bacon (1551-1626) championed the experimental method.

Which of the following statements concerning Charles Darwin is incorrect?

His grandfather, Erasmus Darwin, was vehemently opposed to scientific thought. Explanation: Darwin's grandfather, Erasmus, was actually the first Darwin to propose a scientific theory of evolution

____________________ is the condition in which the internal environment of an organism is maintained within a particular range.

Homeostasis Explanation: Homeostasis is the condition in which the internal environment of an organism is maintained within a particular range

Which of the following statements regarding hydrogen bonding is true?

Hydrogen bonding is possible when hydrogen is in a polar covalent bond. Explanation: A hydrogen bond forms when a partially positive hydrogen atom is attracted to a partially negative atom. Partially positive hydrogen atoms result when hydrogen is covalently bonded to a significantly more electronegative atom, such as oxygen or nitrogen.

Lecithin is a natural detergent because of what molecular property?

It has hydrophobic and hydrophilic regions. Explanation: Lecithin is a natural detergent because it has both hydrophobic and hydrophilic regions. The hydrophobic regions can surround hydrophobic molecules, and the hydrophilic regions interact with the surrounding water molecules.

Which of the following represents the correct order, from largest to smallest, for an individual animal according to the hierarchical structure of biological organization?

Nervous system, brain, nerve cell, molecule Explanation: This is the correct hierarchical sequence, from large to small, for a given organism.

Which of the following orders for the electronegativity of elements is correct?

O > N > S = C > H Explanation: Electronegativity values increase moving up and to the right in the periodic table. Thus, oxygen is the most electronegative of those listed, followed by nitrogen, and so on; hydrogen is the least electronegative.

electrostatics

Pertaining to the tendency for positive and negative charges to attract; the branch of physics dealing with the attraction between positive and negative charges.

______________ urged people to reject religious dogma and to look at the world around them.

Roger Bacon Explanation: Roger Bacon urged others to make a distinction between theology and science, and ultimately reject theology.

SPONCH

Sulfur Phosphorous Oxygen Nitrogen Carbon Hydrogen

____________________ is the smallest unit of life.

The cell Explanation: The cell is the smallest unit that is capable of displaying the characteristics of life, such as reproduction, homeostasis, and growth and development.

gradualism

The hypothesis that major geologic structures are the cumulative result of slow, continuous processes.

A muddy stream flows from under a glacier and into a lake. The stream water is 4°C. The lake water has warmed in the summer sun to about 20°C on top. What will happen to the stream water as it enters the lake?

The muddy stream water will flow along the bottom of the lake. Explanation: The stream water is the densest water can be so it will flow below the rest of the water in the lake.

Water can move through the xylem (circulatory tissue) of plants, apparently in defiance of gravity. What property of water makes it able to do this?

Water molecules can both hydrogen bond with themselves and with other materials. Explanation: Cohesion (which is water molecules bonding to each other) and adhesion both allow water to move up through plant xylem.

Which of the following is an effect of the polarity of the water molecule?

The polarity of water molecules requires it to absorb a lot of heat to change from liquid to gas. Explanation:The hydrogen bonding of water molecules increases the amount of energy required to increase the motion of the molecules relative to a substance without hydrogen bonding.

Potassium atoms (atomic number 19) have one electron in their valence shell. Which statement about potassium atoms is true?

The positive ion of potassium will have a full valence shell.

ionization

The process by which an ion forms.

orbital

The region where an electron is likely to be found.

An atom is

The smallest unit of an element

geology

The study of the history of the earth, especially as recorded in rocks.

catastrophism

The theory, proposed by George Cuvier, that the earth's landscape is shaped by global catastrophes.

All of the following contributed to the body of knowledge of the 17th century except

Thomas Aquinas Explanation: Thomas Aquinas contributed to the body of knowledge of the 13th century.

(True or False) More than one orbital can be in a particular electron shell.

True

An electron shell represents

a level of potential energy that the electron exists in.

Covalent bonds are formed when

a pair of electrons is shared between atoms of similar electronegativities. Explanation: Covalent bonds are formed when a pair of electrons is shared between two atoms of similar electronegativities. If the difference in electronegativity is great, an ionic bond is formed

What is a hypothesis?

a possible explanation Explanation: A hypothesis is a possible explanation for a pattern in observations that can be tested.

If a variety of a trait improves an organism's survival, enabling it to produce more offspring than other members of the population, then the trait is said to be

adaptive Explanation: An adaptive trait improves the fitness of an organism, enabling it to contribute a greater number of offspring relative to other members of the population.

Biology is the study of

all of the above. Explanation: Biology is the study of life in all its forms, both macroscopic and microscopic. As such, biology includes the study of cells, biological molecules, and the flow of energy through living systems.

Which of the following is not approximately 1 amu?

an electron Explanation: An electron has a mass 1/1800th of an amu.

If an atom gains or loses electrons it becomes

an ion. Explanation: An ion is a charged atom or molecule that has gained or lost electrons

The electronegativity of an atom is its ability to

attract electrons. Explanation:Electronegativity is the ability of an atom to attract electrons toward itself in a chemical bond.

The atomic mass of an element is the

average mass of its various isotopes. Explanation: The atomic mass of an element is the average of the masses of its various isotopes, weighted by their relative abundance.

Which of the following is not a characteristic exclusive to life?

capable of movement Explanation: An object that is capable of movement is not necessarily alive. External forces can move inanimate objects.

A hydrophobic compound would dissolve easily in

corn oil. Explanation: Corn oil is a hydrophobic substance, so it would dissolve another hydrophobic substance.

Ions are formed by a change in the number of ______________________, while isotopes have differing numbers of _________________________.

electrons, neutrons Explanation:Isotopes are atoms of the same element with different mass numbers, while ions are the charged form of a particular element. Atoms gain or lose electrons to form charged particles. Both protons and neutrons contribute to the mass number of an atom; however, the number of protons in an atom does not change. Isotopes are atoms of the same element with different numbers of neutrons in their nuclei.

Most of an atom is

empty space. Explanation:Most of an atom is empty space; the volume in which the electron (which is itself very small) may move around.

True or false? An isotope is one of several different forms of an element's atoms that have different atomic masses due to a gain or loss of neutrons or protons.

false Explanation:An isotope is an atom that has more or fewer neutrons. When an atom loses or gains protons it becomes an atom of a different element.

When an atom of fluorine (atomic number 9) becomes an ion, it

gains one electron Explanation: The fluorine atom has seven valence electrons. It gains one more so that the outer shell will have four pairs of electrons.

Which of the following sciences is not a foundation for biology.

genetics Explanation: Genetics is a discipline within biology not a foundation for it.

Hydrophobic interactions

hold nonpolar molecules together. Explanation: Nonpolar molecules are held together by hydrophobic interactions because the nonpolar molecules will aggregate to reduce their interaction with the water molecules.

An atom of which element consists solely of one proton and one electron in its elemental form?

hydrogen

The intermolecular bonds in water are

hydrogen bonds. Explanation: Hydrogen bonds form between water molecules. Hydrogen bonds occur because of the polarity of the bond between hydrogen and oxygen atoms. The partially positive hydrogen atoms of one water molecule are attracted to the partially negative oxygen atoms of two other water molecules.

The bonds broken when water vaporizes to form a gas are

hydrogen bonds. Explanation: The input of heat required to transform water from a liquid to a gas is used to break hydrogen bonds, which hold the molecules together.

Unlike most liquids which steadily decrease in density as they increase in temperature, water exhibits unusual behavior because of the hydrogen bonds between water molecules. Place the following in order of increasing density: ice, water at 4°C, water at 20°C.

ice, water at 20°C, water at 4°C Explanation: Ice floats because it is not as dense as liquid water. When water is at 4°C, it is at its densest.

Water at 4°C occupies ________ volume than it does at 0°C, and water is _______ dense at 4°C than it is at 0°C.

less, more Explanation: The mass of water at 4°C occupies less volume than it does at 0°C; thus, water is more dense at 4°C than it is at 0°C. This is why ice floats on water. Frozen water is less dense because the crystal structure of ice is more loosely spaced, thus it floats on water.

Darwin's position on the HMS Beagle was:

naturalist Explanation: Darwin was taken on the Beagle to make scientific observations and collections during the voyage.

An atom with a high electronegativity is more likely to become which type of ion?

negative Explanation: If two atoms have a difference in electronegativity greater than 2, then an electron transfers from the atom with the lesser to the atom with the greater electronegativity.

Electrons are the __________ particles of atoms.

negatively charged Explanation:Electrons are the small, negatively charged particles that are distributed around the nucleus of an atom.

Isotopes of the same atom differ in the number of

neutrons. Explanation: Atoms of the same element that differ in the number of neutrons are isotopes. Neutral isotopes of an element have the same number of protons and electrons but a different number of neutrons. It is the difference in the number of neutrons that causes the atomic mass to vary between isotopes.

The scientific method outlines a process of testing new ideas. This process involves, in order, which of the following?

observations, hypotheses, experiments, conclusions Explanation: The scientific method is a multistep process used to gather information. The steps are (1)making observations; (2) forming a hypothesis; (3)designing an experiment; (4) gathering data; and (5) drawing a conclusion. The terms hypothesis and theory are not synonymous. A hypothesis is a research question that is tested by experimentation. A theory is more comprehensive than a hypothesis. A theory does not become accepted until its predictions have not been disproved after extensive experimentation and observation. A theory is not considered dogma (absolute fact). Skepticism is the backbone of science!

Hydrophilic interactions

play a role in the solubility of a compound in water. Explanation: Hydrophilic interactions do play a role in the solubility of a substance in water. A hydrophilic substance will readily mix with water because the individual molecules are able to interact with water molecules. Hydrophobic substances, on the other hand, are not soluble in water because the individual molecules are not able to interact with water molecules.

Which of the following type(s) of compounds would you expect to be soluble in water?

polar compounds Explanation: Because water is a polar molecule, it does not readily dissolve nonpolar compounds. Nonpolar compounds tend to be hydrophobic and will aggregate when placed in water in order to minimize their interactions with the polar water molecules. Polar compounds will dissolve readily in water because the partial charges of the polar compound are attracted to the partial charges of the water molecule. Additionally, if there are highly electronegative atoms like oxygen, nitrogen, or fluorine in the polar compound, hydrogen bonds can form between the water molecule and the compound.

The intramolecular bonds in water are

polar covalent. Explanation:The bonds within a water molecule are polar covalent bonds. Oxygen shares two electrons with each hydrogen atom.

The surface tension of water is caused by

the downward net cohesive force on the water molecules at the surface. Explanation: Because of the uneven pull of the water molecules on the surface of the water, there is a driving force pulling the surface molecules downward.

Atoms with low electronegativities are most likely to form what kind of ions?

positively charged ions Explanation: Although the exact magnitude of ionic charge can not be determined from the electronegativity of an atom, it is possible to determine that atoms with low electronegativities are likely to lose electrons to form positive ions. Atoms with high electronegativities are more likely to gain electrons to form negatively charged ions. Atoms that are unable to attract electrons are generally unable to hold their own electrons tightly. The opposite is true for atoms with high electronegativities.

Which of the following components of an atom has a positive charge?

proton Explanation:A proton has a positive charge.

The atomic mass is equal to the number of

protons plus neutrons. Explanation: The number of protons plus the number of neutrons comprise almost all of the mass of the atom because electrons have a negligible mass.

Isotopes are atoms that have the same number of ______________ but different numbers of ________________.

protons, neutrons Explanation: The number of protons does not change between isotopes of the same element. However, the number of neutrons can vary, resulting in isotopes of the same element with different mass numbers.

The atomic number of an atom refers to the number of

protons. Explanation: The atomic number is the number of protons in an atom. The number of electrons may vary depending on whether the atom is carrying a positive or negative charge. The number of neutrons will vary between different isotopes of the same atom. The number of protons of a particular atom never varies, and therefore it defines the atomic number of an atom.

The scientific method involves all of the following except

proving the hypothesis experimentally. Explanation: Experiments do not prove hypotheses. Rather, they are designed to establish that the hypothesis is not incorrect.

Which of the following is not one of the elements that makes up SPONCH?

sodium Explanation:Sodium is not one of the elements that makes up SPONCH, the acronym for the six elements that are found in the majority of molecules present in living organisms. The S in SPONCH stands for sulfur

Some insects are able to walk on water. This is partially a result of the high __________ of water caused by the __________ between water molecules.

surface tension, hydrogen bonds Explanation: Water has the highest surface tension of all known liquids. This surface tension is a result of the hydrogen bonds formed between water molecules which cause the water molecules to be very strongly attracted to each other.

Biology is a _________________ of other sciences.

synthesis Explanation: Biology is a synthesis of the information in other sciences such as geology, chemistry, and physics.

If a compound has a low specific heat, that means

that the amount of heat required to increase the temperature of one gram of the compound is low. Explanation: A low specific heat means that a small amount of energy is necessary to raise the temperature of one gram of a substance one degree Celsius.

Ice is less dense than liquid water because

the open crystal structure of ice. Explanation: Ice floats because it is less dense than water. As water freezes, the hydrogen bonds become rigid, spacing water molecules so that they are less tightly packed—and less dense—than liquid water.

Which of the following scales is least relevent in biology?

the solar system Explanation: Although there are influences of objects away from the planet on living systems, life (in general) does not interact with the solar system and so study at this level is not especially relevent in biology.

An atom is reactive if

the valence shell is not full. Explanation: If the valence shell is partially filled the atom is reactive.

When two oxygen atoms (atomic number 8) interact to form molecular oxygen

they share electrons. Explanation: When two oxygen atoms interact to form molecular oxygen, they share four electrons.

Atoms of very different electronegativities will form a bond in which electrons are

transferred. Explanation:The atom of great electronegativity will pull away an electron from the atom of less electronegativity.

True or false? Any two ions of opposite charge can form an ionic bond.

true Explanation: It is true that any two ions of opposite charge can form an ionic bond, whether or not they became ions because of an electron transfer with each other or with another molecule.

Ionic bonds are formed when

two atoms of opposite charge come together to form an uncharged compound. Explanation:Ionic bonds are formed when two atoms or compounds that have opposite charges are attracted to each other.