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Are you ready for the ultimate biological quiz? Test your knowledge on any of the topics that you’ve learned throughout your studies in biology science, to be crowned the champion!
Questions and Answers
1.
The basic structural and physiological unit of all living organisms is
A.
Aggregate
B.
Organelle
C.
Organism
D.
Cell
E.
Membrane
Correct Answer
D. Cell
Explanation The basic structural and physiological unit of all living organisms is a cell. Cells are the building blocks of life and are responsible for carrying out all the necessary functions for an organism to survive. They contain various organelles that perform specific tasks within the cell, such as the nucleus for genetic material and the mitochondria for energy production. Cells can exist as single-celled organisms or come together to form tissues, organs, and ultimately, complete organisms. The cell membrane surrounds and protects the cell, allowing for the regulation of materials entering and leaving the cell.
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2.
A cell
A.
Can be composed of many different types of tissues
B.
Is found only in plants and animals
C.
Is the smallest entity studied by biologists
D.
May be a distinctive entity or a building block of more complex organisms
E.
All of the above
Correct Answer
D. May be a distinctive entity or a building block of more complex organisms
Explanation The correct answer is "may be a distinctive entity or a building block of more complex organisms." This answer is correct because a cell can exist as a distinct entity, such as a single-celled organism, or it can be a building block of more complex organisms, such as cells that make up tissues, organs, and organisms in plants and animals.
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3.
A species is
A.
And adult organism and all of its offspring
B.
All the organisms that live together in a specific area
C.
A group of similar organisms that aren't capable interbreeding
D.
A group of morphologically similar organisms that can interbreed
E.
A group of organisms in a packet
Correct Answer
D. A group of morpHologically similar organisms that can interbreed
Explanation The correct answer is "a group of morphologically similar organisms that can interbreed." This answer defines a species as a group of organisms that share similar physical characteristics and have the ability to reproduce with one another. This concept is based on the biological species concept, which emphasizes reproductive compatibility as the defining factor for species classification.
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4.
Darwin called teh different reproductive success of individuals with particular variations
A.
Evolution
B.
Inheritance of characteristics
C.
Artificial selection
D.
Cell theory
E.
Natural selection
Correct Answer
E. Natural selection
Explanation Darwin referred to the differential reproductive success of individuals with specific variations as natural selection. This process involves the survival and reproduction of individuals with advantageous traits, leading to the gradual accumulation of these traits in a population over time. Natural selection is a key mechanism of evolution, shaping the characteristics of species and allowing them to adapt to their environment. It is different from artificial selection, where humans intentionally select and breed individuals with desired traits. The answer, therefore, is natural selection.
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5.
Which is the correct order from simple to complex
A.
Cell, tissue, organ, organism, population, community
B.
Cell, tissue, organ, organism, community, population
C.
Community, cell, tissue, organ, organism, population
Correct Answer
A. Cell, tissue, organ, organism, population, community
Explanation The correct order from simple to complex is cell, tissue, organ, organism, population, community. This order follows the hierarchical structure of living organisms, starting from the basic unit of life (cell), progressing to the formation of tissues, organs, and finally, complete organisms. Once multiple organisms of the same species exist in a particular area, they form a population. And when multiple populations interact and coexist in a specific area, they form a community.
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6.
Which of the following is not true?
A.
Biology is the study of life
B.
Metabolism refers to all the chemical reactions within a cell
C.
Adaption is modifications the make an organism better able to function
D.
Hypothesis is an educated guess that can be tested
E.
Bacteria are multicellular
Correct Answer
E. Bacteria are multicellular
Explanation The statement "bacteria are multicellular" is not true. Bacteria are actually unicellular organisms, meaning they consist of a single cell. They do not have specialized structures or organs like multicellular organisms.
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7.
Plants are
A.
Eykaryotic, multicellular photosynthesizers
B.
Eykaryotic, multicellular heterotrauphs
C.
Eykaryotic, multicellular autotrophs
D.
Prokaryotic, multicellular autotrophs
Correct Answer
A. Eykaryotic, multicellular pHotosynthesizers
Explanation Plants are eukaryotic, multicellular photosynthesizers. This means that they are composed of cells with a true nucleus (eukaryotic), they are made up of multiple cells (multicellular), and they have the ability to produce their own food through photosynthesis. Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. This explanation accurately describes the characteristics and abilities of plants.
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8.
An evolutionary tree
A.
Shows evolutionary relationship
B.
Places the most closely related groups on the same branch
C.
Places the organisms that share a common ancestor on the same branch of the tree
D.
Shows the order in which populations split and evolved into new species
E.
All of the above
Correct Answer
E. All of the above
Explanation An evolutionary tree shows the evolutionary relationship between different groups of organisms. It places the most closely related groups on the same branch, indicating their close genetic similarity. Additionally, it places organisms that share a common ancestor on the same branch, showing their shared evolutionary history. The tree also shows the order in which populations split and evolved into new species, providing a timeline of speciation events. Therefore, all of the given options correctly describe the features of an evolutionary tree.
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9.
After observing that fish live in clean water but not polluted water, you make the statement "polluted water kills fish" Your statement is an example of
A.
Scientific inquiry
B.
Biological evolution
C.
A law
D.
A hypothesis
E.
A theory
Correct Answer
D. A hypothesis
Explanation The given statement "polluted water kills fish" is an example of a hypothesis. A hypothesis is a tentative explanation or prediction that can be tested through further observations or experiments. In this case, the observation that fish live in clean water but not polluted water leads to the hypothesis that polluted water kills fish. This hypothesis can be tested by conducting experiments or further observations to gather evidence supporting or refuting the statement.
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10.
After formulating a hypothesis a scientist
A.
Proves the hypothesis true or false
B.
Tests the hypothesis
C.
Decides how to best avoid having a control
D.
Makes sure environmental conditions are just right
E.
Formulates a scientific theory
Correct Answer
B. Tests the hypothesis
Explanation After formulating a hypothesis, a scientist tests the hypothesis to determine its validity. This involves conducting experiments or gathering data to evaluate whether the hypothesis is true or false. Testing the hypothesis is an essential step in the scientific method as it allows scientists to gather evidence and make conclusions based on empirical observations.
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11.
All cells of an organism
A.
Contain the same products
B.
Have identical functions
C.
Have the same genome
D.
Have some genes that differ
E.
Express all of their genes at the same time during development
Correct Answer
C. Have the same genome
Explanation All cells of an organism having the same genome means that they contain the same set of genetic material or DNA. This implies that they have the same instructions for building and functioning, although they may differ in terms of gene expression and function. The genome is the complete set of genes or genetic material present in an organism, and having the same genome ensures that all cells have the potential to develop into any type of cell in the organism.
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12.
35. Which of the following questions cannot be answered
using the hypothetico-deductive method?
A.
A. Are bees more attracted to red roses than to yellow roses?
B.
B. Are red roses more beautiful than yellow roses?
C.
D. Making a prediction
D.
D. Do red roses bloom earlier than yellow roses?
E.
E. Are red roses more susceptible to mildew than yellow roses?
Correct Answer
B. B. Are red roses more beautiful than yellow roses?
Explanation The hypothetico-deductive method is a scientific method that involves formulating a hypothesis, making predictions based on that hypothesis, and then testing those predictions through experimentation or observation. This method can be used to answer questions that can be tested and have observable outcomes. However, the question of whether red roses are more beautiful than yellow roses is subjective and cannot be objectively tested or measured, making it unsuitable for the hypothetico-deductive method.
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13.
The fact that cells come from preexisting cells is a part of the _____ theory
A.
Animal
B.
Genetic
C.
Cell
D.
Plant
E.
None of the above
Correct Answer
C. Cell
Explanation The fact that cells come from preexisting cells is a fundamental principle of the cell theory. The cell theory states that all living organisms are composed of cells, cells are the basic units of structure and function in living organisms, and cells come from preexisting cells through cell division. This theory was proposed by Matthias Schleiden and Theodor Schwann in the 19th century and is a cornerstone of modern biology.
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14.
Photosynthesis was a major evolutionary milestone because
A.
A. photosynthetic organisms contributed oxygen to the environment, which led to the evolution of aerobic organisms.
B.
B. photosynthesis led to conditions that allowed life to arise on land.
C.
C. photosynthesis is the only metabolic process that can convert light energy to chemical energy.
D.
D. All of the above
Correct Answer
D. D. All of the above
Explanation Photosynthesis was a major evolutionary milestone because it contributed oxygen to the environment, which led to the evolution of aerobic organisms. Additionally, photosynthesis led to conditions that allowed life to arise on land. Furthermore, photosynthesis is the only metabolic process that can convert light energy to chemical energy. Therefore, all of these factors make photosynthesis a significant event in evolution.
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15.
The info needed too produce proteins is contained in
A.
Nutrients
B.
Genes
C.
Evolution
D.
Organs
E.
All
Correct Answer
B. Genes
Explanation Genes contain the necessary information to produce proteins. Proteins are essential for various biological processes and functions in the body. Genes are segments of DNA that carry the instructions for building proteins. They provide the blueprint for the synthesis of proteins, which are responsible for carrying out most of the work in cells. Therefore, genes play a crucial role in determining the structure, function, and characteristics of organisms.
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16.
Ecology is the study of how
A.
Genes code for proteins
B.
Species interact with each other and the environment
C.
Organ systems function
D.
None
Correct Answer
B. Species interact with each other and the environment
Explanation Ecology is the study of how species interact with each other and the environment. This field of science focuses on understanding the relationships between organisms and their surroundings, including the interactions between different species and their physical and biological environment. By studying these interactions, ecologists can gain insights into the balance of ecosystems, the impact of human activities on the environment, and the conservation of biodiversity.
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17.
For a hypothesis to be scientifically valid, it must be ____ and it must be possible to ____ it
A.
Testable: prove
B.
Testable: reject
C.
Controlled: prove
D.
Controlled: reject
Correct Answer
B. Testable: reject
Explanation In order for a hypothesis to be scientifically valid, it must be testable, meaning that it can be subjected to experimentation or observation to gather evidence. Additionally, it must be possible to reject the hypothesis based on the results of the test. This means that the hypothesis should be falsifiable, allowing for the possibility of disproving it if the evidence does not support it. Therefore, the correct answer is "testable: reject."
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18.
Organisms are named using first their _______ and then their
_______.
A.
A. species; genus
B.
B. genus; domain
C.
C. domain; genus
D.
D. genus; species
Correct Answer
D. D. genus; species
Explanation Organisms are named using first their genus and then their species. This naming system is known as binomial nomenclature and was developed by Carl Linnaeus. The genus is a broader category that groups similar organisms together, while the species is a more specific identifier that distinguishes one organism from another within the same genus. This naming system allows for precise and standardized identification of organisms, facilitating communication and classification in the field of biology.
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19.
Organisms
A.
Are related by decent to a common ancestor
B.
Share the same genetic code
C.
Are composed of cells
D.
Carry out similar chemical reactions
E.
All of the above
Correct Answer
E. All of the above
Explanation All of the above options are correct because organisms share a common ancestor, which means they have similar genetic codes. They are composed of cells and carry out similar chemical reactions. Therefore, all of these statements are true and explain the relationship between organisms.
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20.
Why study biology?
A.
Medicine depends on biological knowledge
B.
Agriculture "
C.
It enriches our lives
D.
All of the above
Correct Answer
D. All of the above
Explanation Studying biology is important because it has various applications in different fields. Medicine heavily relies on biological knowledge to understand the human body and develop treatments for diseases. Agriculture also benefits from biology as it helps in improving crop yields and developing pest control methods. Additionally, studying biology enriches our lives by providing a deeper understanding of the natural world and the diversity of life on Earth. Therefore, all of the given options are valid reasons to study biology.
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21.
Which of the subatomic particles contribute almost no weight to the atom?
A.
Protons in the shell
B.
Electrons in the nucleus
C.
Protons in the nucleus
D.
Electrons at various energy levels
Correct Answer
D. Electrons at various energy levels
Explanation Electrons at various energy levels contribute almost no weight to the atom. While protons and neutrons are located in the nucleus and have significant mass, electrons are much smaller and have negligible mass compared to protons and neutrons. Although electrons play a crucial role in determining the chemical properties and behavior of atoms, their individual mass is so small that it does not significantly contribute to the overall weight of an atom.
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22.
1. The atomic number of an element
A.
A. equals the number of neutrons in an atom.
B.
B. equals the number of protons in an atom.
C.
C. equals the number of protons minus the number of
neutrons.
D.
D. equals the number of neutrons plus the number of protons.
E.
E. depends on the isotope.
Correct Answer
B. B. equals the number of protons in an atom.
Explanation The atomic number of an element refers to the number of protons in an atom. This is a fundamental property of an element and determines its placement on the periodic table. The number of neutrons and electrons in an atom can vary, but the number of protons remains constant for a specific element. Therefore, option b is the correct answer.
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23.
The mass number of an element depends on the number of _____ it contains
A.
Neutrons in the N
B.
Protons in the atom
C.
Protons + electrons
D.
Protons + neutrons (same as mass)
Correct Answer
D. Protons + neutrons (same as mass)
Explanation The mass number of an element refers to the total number of protons and neutrons present in its nucleus. This is because protons and neutrons have approximately the same mass, and together they contribute to the overall mass of the atom. The number of electrons, on the other hand, does not significantly affect the mass number as they have a negligible mass compared to protons and neutrons. Therefore, the correct answer is "protons + neutrons (same as mass)".
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24.
Atomic weight is
A.
Protons
B.
Neutrons
C.
Electrons
D.
All of the above
E.
Protons +neutrons
Correct Answer
E. Protons +neutrons
Explanation The atomic weight is determined by the sum of the protons and neutrons in an atom's nucleus. Electrons, although important for determining the atom's chemical properties, have a negligible mass compared to protons and neutrons. Therefore, the correct answer is "protons + neutrons."
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25.
An element has a weight is 131.3 the reason this number is not a round number is
A.
Atomic weight includes the weigh of electrons
B.
Atomic weight is the average of the weigh of all of the element's isotopes
C.
Electrons do not have a whole unit weight
D.
Atomic weight doesn't include protons
Correct Answer
B. Atomic weight is the average of the weigh of all of the element's isotopes
Explanation The reason the weight of an element is not a round number is because atomic weight is the average of the weight of all of the element's isotopes. Isotopes are variants of an element that have different numbers of neutrons in their nucleus. Since different isotopes have different weights, the average atomic weight is a decimal number rather than a round number.
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26.
Which is not true of isotopes
A.
They all have the same atomic number
B.
They have the same number of protons
C.
They have the same number of neutrons
D.
They have the same number of electrons
E.
They have the same chemical properties
Correct Answer
C. They have the same number of neutrons
Explanation Isotopes are atoms of the same element that have different numbers of neutrons. This means that they have the same atomic number (number of protons) and the same number of electrons, but they differ in their mass number (number of protons + neutrons). Therefore, the statement "they have the same number of neutrons" is not true for isotopes.
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27.
Of the following atomic configurations, the one that has an
atomic mass of 14 is the atom with
A.
A. 14 neutrons.
B.
B. 14 electrons.
C.
C. 7 neutrons and 7 electrons.
D.
D. 7 protons and 7 electrons.
E.
E. 6 protons and 8 neutrons
Correct Answer
E. E. 6 protons and 8 neutrons
Explanation The atomic mass of an atom is determined by the total number of protons and neutrons in its nucleus. The atomic number of an atom is equal to the number of protons it has. In this case, the atom with an atomic mass of 14 must have 6 protons (since the atomic number of carbon is 6) and 8 neutrons. Therefore, the correct answer is e. 6 protons and 8 neutrons.
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28.
The result of sharing of electrons between atoms is _________ bonds
A.
Covalent
B.
Ionic
C.
Hydrogen
D.
Neutral
Correct Answer
A. Covalent
Explanation When atoms share electrons, they form covalent bonds. In covalent bonds, the shared electrons are attracted to the positively charged nuclei of both atoms, creating a strong bond. This type of bond is commonly found in molecules where atoms need to achieve a stable electron configuration by sharing electrons with each other. Ionic bonds involve the transfer of electrons, hydrogen bonds are formed between a hydrogen atom and an electronegative atom, and neutral bonds are not a recognized type of chemical bond.
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29.
Phosphorus has an atomic weight of 30.974 and 15 protons. how many neutrons does it have?
A.
12
B.
15
C.
16
D.
8
E.
31
Correct Answer
C. 16
Explanation The atomic weight of an element is the sum of the number of protons and neutrons in its nucleus. Since phosphorus has 15 protons, to find the number of neutrons we subtract the atomic weight (30.974) from the number of protons. Therefore, the number of neutrons in phosphorus is 16.
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30.
Which of the following statements about covalent bonds is not true?
A.
It's stronger than a hydrogen bond
B.
It can form between atoms of the same element
C.
Only single covalent bonds can form between 2 elements
D.
Results from the sharing of electrons
Correct Answer
C. Only single covalent bonds can form between 2 elements
Explanation Covalent bonds can form between two atoms of the same element or different elements. They are formed by the sharing of electrons between atoms, which results in the formation of a stable molecule. Covalent bonds are generally stronger than hydrogen bonds, which are formed by the attraction between a hydrogen atom and an electronegative atom. Therefore, the statement "only single covalent bonds can form between 2 elements" is not true, as multiple covalent bonds, such as double or triple bonds, can also form between elements.
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31.
An atom that has 2 electrons in the outer shell would likely
A.
Share to aquire a completed outer shell
B.
Lose these two electrons and become a negatively charged ion
C.
Lose these two electrons and become a positively charged ion
D.
Bond with carbon to form hydrogen
Correct Answer
C. Lose these two electrons and become a positively charged ion
Explanation An atom that has 2 electrons in the outer shell would likely lose these two electrons and become a positively charged ion. This is because atoms tend to gain or lose electrons in order to achieve a stable electron configuration, typically with a full outer shell. By losing two electrons, the atom will have a net positive charge since the number of protons in the nucleus will be greater than the number of electrons orbiting the nucleus.
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32.
When an atom gains electrons it
A.
Becomes an anion
B.
Becomes a cation
C.
Forms covalent bonds
D.
Gains atomic mass
Correct Answer
A. Becomes an anion
Explanation When an atom gains electrons, it becomes an anion. An anion is a negatively charged ion that forms when an atom gains one or more electrons. The gain of electrons results in an increase in the overall negative charge of the atom, leading to the formation of an anion. This is in contrast to a cation, which is a positively charged ion that forms when an atom loses electrons. The formation of covalent bonds involves the sharing of electrons between atoms, while gaining atomic mass refers to an increase in the total mass of the atom, which is not directly related to the gain of electrons.
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33.
A covalent bond is indicated by
A.
+/- charges attached to the ion
B.
Dotted lines between hydrogen atoms
C.
Concentric circles around the nucleus
D.
Overlapping electron shells or straight lines between atomic symbols
Correct Answer
D. Overlapping electron shells or straight lines between atomic symbols
Explanation A covalent bond is indicated by overlapping electron shells or straight lines between atomic symbols. In a covalent bond, two atoms share electrons in order to achieve a stable electron configuration. The overlapping of electron shells or the straight lines between atomic symbols represent the sharing of electrons between the atoms. This sharing of electrons creates a bond between the atoms, allowing them to form a stable molecule.
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34.
In which of these are the electrons shared unequally?
A.
Double c.b.
B.
Nonpolar c.b.
C.
Polar c.b.
D.
Triple c.b.
Correct Answer
C. Polar c.b.
Explanation In a polar covalent bond, the electrons are shared unequally between the atoms involved. This occurs when there is a difference in electronegativity between the atoms, causing one atom to have a stronger pull on the shared electrons. As a result, the electron density is shifted towards the more electronegative atom, creating partial positive and partial negative charges within the molecule. This unequal sharing of electrons leads to a polar covalent bond.
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35.
In the molecule CH4,
A.
All atoms have eight electrons in the outer shell
B.
All atoms are sharing electrons
C.
Carbon could accept more H atoms
Correct Answer
B. All atoms are sharing electrons
Explanation In the molecule CH4, all atoms are sharing electrons. This is because carbon has four valence electrons and needs four more electrons to complete its octet. Each hydrogen atom contributes one electron, forming four covalent bonds with carbon. This allows carbon to complete its octet and hydrogen to have two electrons in its outer shell. Therefore, all atoms in CH4 are sharing electrons to achieve a stable electron configuration.
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36.
The periodic table tells us
A.
The atomic number, symbol and mass
B.
How many shells an atom has
C.
How many electrons are in the outer shell
D.
Whether the atom will react or not
E.
All of these
Correct Answer
E. All of these
Explanation The periodic table provides information about the atomic number, symbol, and mass of each element, which helps in identifying and categorizing elements. It also indicates the number of electron shells an atom has, which determines its electronic configuration. Additionally, the periodic table allows us to determine the number of electrons in the outermost shell, which is crucial for understanding an atom's reactivity and its tendency to form chemical bonds. Therefore, the correct answer is "all of these" because the periodic table encompasses all the mentioned aspects.
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37.
Which of the following is not true?
A.
The molecular formula consists of the symbol and teh qty of each atom in a molecule
B.
The structural formula shows which atoms are bonded to each other
C.
C6H12O6 is a molecular formula
D.
C6H12O6 is a structural formula
Correct Answer
D. C6H12O6 is a structural formula
Explanation The given statement "C6H12O6 is a structural formula" is not true because C6H12O6 is actually a molecular formula. A molecular formula represents the actual number of atoms of each element in a molecule, while a structural formula shows the arrangement and bonding of atoms in a molecule.
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38.
Matter is anything that
A.
Has mass
B.
Has volume
C.
Has relevance
D.
A and b
E.
All
Correct Answer
D. A and b
Explanation Matter is anything that has mass and volume. Mass refers to the amount of matter in an object, while volume refers to the amount of space that matter occupies. Both mass and volume are essential characteristics of matter, as they help define its physical properties and behavior. Therefore, the correct answer is "a and b" because matter must possess both mass and volume.
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39.
Which is not true?
A.
An element is a substance that cannot be broken down without completely changing its properties
B.
An atom is the smallest part of an element that retains the properties of the element
C.
A compound is a substance having two or more different elements bonded together
D.
A molecule is more than one atom bonded together
E.
All of the above are true
Correct Answer(s)
A. An element is a substance that cannot be broken down without completely changing its properties E. All of the above are true
Explanation All of the above statements are true except for the statement that an element is a substance that cannot be broken down without completely changing its properties. Elements can be broken down into smaller particles called atoms, but the properties of the element remain the same.
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40.
WHich of he following statements about water is not true?
A.
It has a relatively low heat capacity therefore it does not resist change in temperature well
B.
Its solid form is less dense than its liquid form, which is why ice floats
C.
It is the most effective solvent of polar molecules
D.
It is cohesive and adhesive
E.
It has a relatively high heat of evaporation
Correct Answer
E. It has a relatively high heat of evaporation
Explanation Water does have a relatively high heat of evaporation. This means that it requires a large amount of energy to change from a liquid to a gas, which is why water has a cooling effect when it evaporates.
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41.
What are the 4 major elements that make up organisms
A.
Carbon, hydrogen, potassium, argon
B.
Carbon, hydrogen,, nitrogen, O
C.
C, H, O, Cl
D.
C, H, N, S
Correct Answer
B. Carbon, hydrogen,, nitrogen, O
Explanation The answer is carbon, hydrogen, nitrogen, and oxygen because these four elements are essential for the formation and functioning of organic molecules in organisms. Carbon is the backbone of organic compounds, hydrogen is involved in chemical reactions and maintaining pH balance, nitrogen is necessary for building proteins and nucleic acids, and oxygen is required for cellular respiration and energy production. These elements are found in all living organisms and play vital roles in their structure and metabolism.
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42.
The part of the atom that determines how the atom behaves chemically is the
A.
Proton
B.
Electron
C.
Neutron
D.
Innermost shell
Correct Answer
B. Electron
Explanation The electron is the part of the atom that determines how the atom behaves chemically. This is because electrons are negatively charged particles that are located in the outermost region of the atom called the electron cloud. Electrons are involved in chemical reactions by forming bonds with other atoms, which determines the atom's ability to gain, lose, or share electrons. Therefore, the behavior of the atom in chemical reactions is primarily determined by the arrangement and movement of electrons.
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43.
An atom that is neutrally charged has
A.
Only neutrons
B.
Neutrons = electrons
C.
Neutrons=protons
D.
Protons = electrons
E.
No charged particles
Correct Answer
D. Protons = electrons
Explanation An atom that is neutrally charged means that it has an equal number of protons and electrons. Protons have a positive charge, while electrons have a negative charge. When the number of protons and electrons is the same, their charges cancel each other out, resulting in a neutral charge for the atom. Therefore, the statement "protons = electrons" is the correct answer.
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44.
The best reference source for the atomic number and mass number of an element is
A.
Chemistry book
B.
Dictionary
C.
Periodic table
D.
Biology book
Correct Answer
C. Periodic table
Explanation The periodic table is the best reference source for the atomic number and mass number of an element because it provides a comprehensive and organized list of all known elements. It displays the atomic number, which represents the number of protons in an atom's nucleus, and the mass number, which represents the total number of protons and neutrons in an atom. The periodic table also provides additional information about each element, such as its symbol, atomic weight, and electron configuration. This makes it a reliable and convenient resource for obtaining accurate information about the atomic and mass numbers of elements.
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45.
Which of the following elements is the most chemically reactive
A.
H
B.
He
C.
N
D.
Ar
E.
They're all the same
Correct Answer
A. H
Explanation Hydrogen (H) is the most chemically reactive element among the options given. This is because it has only one electron in its outermost shell, making it highly unstable and eager to gain or lose an electron to achieve a stable configuration. This characteristic makes hydrogen highly reactive, allowing it to easily form chemical bonds with other elements. In contrast, helium (He), nitrogen (N), and argon (Ar) have full outer electron shells and are therefore more stable and less likely to react with other elements.
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46.
All of the following elements follow the octet rule except for
A.
S
B.
Cl
C.
H
D.
N
E.
C
Correct Answer
C. H
Explanation The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration with 8 electrons in their outermost energy level. Sulfur (S), Chlorine (Cl), Nitrogen (N), and Carbon (C) all have the ability to gain, lose, or share electrons to achieve an octet. However, Hydrogen (H) only requires 2 electrons to achieve a stable electron configuration, so it does not follow the octet rule.
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47.
In a H molecule, the two elements are held together by
A.
Hydrogen bonds
B.
Shared electrons
C.
Van der Waals forces
D.
Ionic attractions
Correct Answer
A. Hydrogen bonds
Explanation In a H molecule, the two elements are held together by hydrogen bonds. Hydrogen bonds occur when a hydrogen atom is bonded to a highly electronegative atom, such as oxygen or nitrogen, and forms a weak attraction with another electronegative atom in a different molecule. This type of bond is relatively weak compared to covalent or ionic bonds, but it still plays an important role in stabilizing molecules and structures, particularly in biological systems.
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48.
A single covalent bond chemical bond represents the sharing of how many electrons?
A.
1
B.
2
C.
3
D.
4
Correct Answer
B. 2
Explanation A single covalent bond represents the sharing of two electrons. In a covalent bond, two atoms share a pair of electrons in order to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outermost energy levels and become more stable. Therefore, the correct answer is 2.
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49.
Two carbon atoms held together in a double covalent bond share _____ electrons
A.
1
B.
2
C.
4
D.
6
E.
12
Correct Answer
C. 4
Explanation In a double covalent bond, two carbon atoms share four electrons. This is because each carbon atom contributes two electrons to the bond, resulting in a total of four shared electrons.
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50.
Oxygen forms ____ bonds, Carbon forms __ bonds, and H forms ___ bonds
A.
1 4 1
B.
4 4 4
C.
2 4 0
D.
2 4 1
Correct Answer
D. 2 4 1
Explanation Oxygen forms 2 bonds, Carbon forms 4 bonds, and Hydrogen forms 1 bond. This is because oxygen has 6 valence electrons and needs 2 more to complete its octet, so it forms 2 bonds. Carbon has 4 valence electrons and needs 4 more to complete its octet, so it forms 4 bonds. Hydrogen has 1 valence electron and needs 1 more to complete its duet, so it forms 1 bond.
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