1.
How many different elements are in a water molecule?
Correct Answer
B. 2
Explanation
A water molecule consists of two hydrogen atoms and one oxygen atom, making a total of three different elements in the molecule.
2.
Which of the following are electrically neutral?
Correct Answer
B. Neutron
Explanation
Neutrons are electrically neutral because they have no charge. Unlike protons, which have a positive charge, and electrons, which have a negative charge, neutrons have no charge at all. This is due to the fact that they contain equal numbers of positive and negative particles, balancing out their overall charge. Therefore, neutrons do not interact with electric fields and are considered electrically neutral.
3.
There are about as many atoms of air in our lungs at any moment as there are breaths of air in the atmosphere of
Correct Answer
D. The whole world.
Explanation
The statement suggests that the number of atoms of air in our lungs at any given moment is comparable to the number of breaths of air in the atmosphere of the whole world. This implies that the number of atoms in our lungs is extremely large, as the atmosphere of the whole world contains a vast amount of air. The comparison to a large auditorium, city, or even the United States would not adequately capture the scale of the number of atoms in our lungs. Therefore, the correct answer is the whole world.
4.
Atoms heavier than helium were made by
Correct Answer
B. Thermonuclear fusion.
Explanation
Atoms heavier than helium, such as carbon, oxygen, and iron, are not formed through photosynthesis or radiant energy conversion. They are created through thermonuclear fusion, a process that occurs in the cores of stars. During thermonuclear fusion, lighter elements, like hydrogen and helium, combine to form heavier elements through high temperatures and pressure. This process releases a tremendous amount of energy and is responsible for the creation of heavier atoms in the universe. Therefore, the correct answer is thermonuclear fusion.
5.
An atomic mass unit (amu) is 1/12 the mass of
Correct Answer
D. A carbon atom.
Explanation
An atomic mass unit (amu) is a unit of measurement used to express the mass of atomic and subatomic particles. It is defined as 1/12 the mass of a carbon atom. This means that if the mass of a carbon atom is taken as 12 amu, then the mass of an electron is approximately 1/12 amu. Therefore, the correct answer is a carbon atom.
6.
If we doubled the magnifying power of the most powerful optical microscope in the world, we would
Correct Answer
C. Still not be able to see or pHotograpH an atom.
Explanation
If we were to double the magnifying power of the most powerful optical microscope in the world, it would still not be enough to see or photograph an atom. Atoms are much smaller than the resolution limit of optical microscopes, which is typically around 200 nanometers. Even with increased magnification, the size of atoms, which are on the scale of picometers (trillionths of a meter), would still be far beyond the capabilities of optical microscopy. To visualize or capture images of atoms, techniques such as electron microscopy or scanning probe microscopy are required.
7.
Which of these atoms has the most mass?
Correct Answer
D. Uranium
Explanation
Uranium has the most mass among the given atoms. Uranium is a heavy metal and has an atomic mass of 238.03 atomic mass units (AMU). In comparison, hydrogen has an atomic mass of 1 AMU, iron has an atomic mass of 55.85 AMU, and lead has an atomic mass of 207.2 AMU. Therefore, uranium has the highest mass among these atoms.
8.
Which of these statements is true?
Correct Answer
D. Molecules are the smallest subdivision of matter that still retains chemical properties of a substance.
Explanation
The correct answer is "Molecules are the smallest subdivision of matter that still retains chemical properties of a substance." This statement is true because molecules are composed of atoms bonded together, and they retain the chemical properties of the atoms that make them up. Molecules can be further broken down into atoms, but at that point, the chemical properties of the substance would be lost. Therefore, molecules are the smallest subdivision of matter that still retains the chemical properties of a substance.
9.
Which of the following statements is true?
Correct Answer
B. There are only about 100 different kinds of atoms that combine to form all substances.
10.
What makes an element distinct?
Correct Answer
A. The number of protons
Explanation
The number of protons in an element determines its atomic number, which is unique to each element. This atomic number defines the element and distinguishes it from other elements in the periodic table. The number of neutrons and electrons can vary within an element, but the number of protons remains constant. Therefore, the number of protons is what makes an element distinct.
11.
Brownian motion has to do with the
Correct Answer
D. Random motions of atoms and molecules.
Explanation
Brownian motion refers to the random movements of atoms and molecules. It was first observed by Robert Brown in 1827, who noticed the erratic movement of pollen particles in water. This phenomenon provided evidence for the existence of atoms and molecules, as their random motion could be observed under a microscope. Brownian motion is a result of the constant collisions between particles in a fluid, causing them to move in a random and unpredictable manner. It is not specifically related to the size of atoms, atomic vibrations, or rhythmic movements in a liquid, but rather the overall random motion of atoms and molecules.
12.
Which of the following is not a compound?
Correct Answer
A. Air
Explanation
Air is not a compound because it is a mixture of different gases such as nitrogen, oxygen, carbon dioxide, and others. A compound is a substance that is made up of two or more elements chemically combined in a fixed ratio. In the case of air, it is not chemically bonded and its composition can vary. Therefore, air does not fit the definition of a compound.
13.
Which of the following is not a mixture?
Correct Answer
E. None. All of the above choices are mixtures.
Explanation
All of the options listed - granite, cake, air, and beach sand - are examples of mixtures. Granite is a mixture of different minerals, cake is a mixture of ingredients like flour, sugar, and eggs, air is a mixture of gases, and beach sand is a mixture of different types of sand particles. Therefore, the correct answer is that none of the options listed are not a mixture.
14.
In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of
Correct Answer
C. Orbital electrons.
Explanation
In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of orbital electrons. Protons carry a positive charge, while electrons carry a negative charge. To maintain overall neutrality, the number of protons (positive charges) must be equal to the number of electrons (negative charges). Neutrons, on the other hand, do not carry any charge and do not contribute to the overall electrical neutrality of the atom. Quarks are elementary particles that make up protons and neutrons, but they are not directly involved in balancing the charges in an atom. Therefore, the correct answer is orbital electrons.
15.
The smallest particle of those listed below is
Correct Answer
E. A quark.
16.
A molecule has
Correct Answer
D. All of these
Explanation
The correct answer is "all of these" because a molecule can have mass, which refers to the amount of matter it contains. Additionally, a molecule has structure, which refers to the arrangement of atoms within the molecule. Lastly, a molecule has energy, which can be in the form of kinetic energy due to its movement or potential energy due to its position or chemical bonds. Therefore, all of these options accurately describe characteristics of a molecule.
17.
Solid matter is mostly empty space. The reason solids don't fall through one another is because
Correct Answer
D. Of electrical forces.
Explanation
Solid matter is mostly empty space because atoms are made up of a nucleus (containing protons and neutrons) surrounded by electrons. These electrons create electrical forces that repel each other, preventing the atoms from collapsing into one another. This repulsion is what gives solids their rigidity and prevents them from falling through one another. Therefore, the correct answer is "of electrical forces."
18.
A force that determines the chemical properties of an atom is a(n)
Correct Answer
D. Electrical force.
Explanation
The force that determines the chemical properties of an atom is the electrical force. This force is responsible for the attraction and repulsion between charged particles, such as electrons and protons. It determines how atoms interact with each other to form chemical bonds and compounds. Friction force, nuclear force, and gravitational force do not directly influence the chemical properties of atoms.
19.
Which has the greatest number of protons in its nucleus?
Correct Answer
C. Lead
Explanation
Lead has the greatest number of protons in its nucleus compared to the other options. Protons are positively charged particles found in the nucleus of an atom. The atomic number of an element represents the number of protons in its nucleus. Gold has an atomic number of 79, mercury has an atomic number of 80, lead has an atomic number of 82, and silver has an atomic number of 47. Therefore, lead has the greatest number of protons in its nucleus.
20.
The air in this room has
Correct Answer
D. All of these
Explanation
The air in a room possesses mass, as it is composed of molecules that have mass. It also has weight, as it is affected by gravity and exerts a downward force. Additionally, air has energy, in the form of kinetic energy due to the movement of its molecules and potential energy due to its position. Therefore, the correct answer is "all of these."
21.
Compared to the energy it takes to separate oxygen and hydrogen from water, the amount of energy given off when they recombine is
Correct Answer
E. The same.
Explanation
When oxygen and hydrogen are separated from water, it requires a certain amount of energy. However, when they recombine, an equal amount of energy is released. This is due to the law of conservation of energy, which states that energy cannot be created or destroyed, only transferred or transformed. Therefore, the amount of energy given off when oxygen and hydrogen recombine is the same as the energy it takes to separate them from water.
22.
When carbon and oxygen atoms combine, energy is
Correct Answer
B. Given off by the reaction.
Explanation
When carbon and oxygen atoms combine, they form carbon dioxide (CO2) through a chemical reaction called combustion. During this process, energy is released in the form of heat and light. This is because the bonds between the carbon and oxygen atoms in the reactants are stronger than the bonds in the products. Therefore, the excess energy is given off by the reaction.
23.
If an astronaut landed on a planet made of antimatter, there would be an explosion and
Correct Answer
D. The astronaut and an equal amount of the planet would both annihilate.
Explanation
When an astronaut lands on a planet made of antimatter, there would be a collision between matter and antimatter. Antimatter is composed of antiparticles that have opposite charges to their corresponding particles in regular matter. When matter and antimatter collide, they annihilate each other, releasing a tremendous amount of energy in the form of an explosion. Therefore, both the astronaut and an equal amount of the planet would be annihilated in this scenario.
24.
In our part of the universe, antimatter is
Correct Answer
C. Short-lived.
Explanation
Antimatter is considered short-lived in our part of the universe because it quickly annihilates upon contact with matter, resulting in the release of a large amount of energy. This annihilation process makes it difficult for antimatter to exist for an extended period of time.
25.
Assuming all the atoms exhaled by Julius Caesar in his last dying breath are still in the atmosphere, then we probably breathe one of those atoms with each
Correct Answer
A. Single breath.
Explanation
Since the question assumes that all the atoms exhaled by Julius Caesar are still in the atmosphere, it implies that these atoms are constantly circulating in the air we breathe. Therefore, with each single breath, it is highly likely that we would inhale at least one of those atoms.
26.
Nuclei of atoms that make up a newborn baby were made in
Correct Answer
C. Ancient stars.
Explanation
The correct answer is "ancient stars." This is because the nuclei of atoms that make up a newborn baby were formed through nuclear reactions in the cores of ancient stars. These stars went through the process of nuclear fusion, where lighter elements combined to form heavier elements. When these stars eventually exploded as supernovae, they dispersed their enriched materials into space. These materials then came together to form new stars, planets, and eventually, living organisms like humans. Therefore, the nuclei of atoms in a newborn baby were ultimately made in ancient stars.
27.
Compared to the atoms that make up the body of an elderly person, the atoms that make up the body of a newborn baby are
Correct Answer
C. The same age.
Explanation
The explanation for the correct answer is that atoms are not created or destroyed, they only rearrange to form different molecules. Therefore, the atoms that make up the body of a newborn baby are the same age as the atoms that make up the body of an elderly person. The concept of age does not apply to individual atoms, as they have been in existence since the formation of the universe.
28.
The reason a granite block is mostly empty space is that the atoms in the granite are
Correct Answer
B. Mostly empty space themselves.
Explanation
The correct answer is "mostly empty space themselves" because the atoms in granite, like all matter, have a nucleus at the center and electrons orbiting around it. The size of the nucleus is extremely small compared to the overall size of the atom, so most of the atom's volume is empty space. Therefore, the atoms in granite are mostly empty space themselves.
29.
The weight of matter comes mostly from its
Correct Answer
A. Protons.
Explanation
The weight of matter comes mostly from its protons. Protons are subatomic particles found in the nucleus of an atom and they carry a positive charge. The weight of an atom is determined by the combined mass of its protons and neutrons, with electrons contributing very little to the overall weight. Therefore, the protons, along with the neutrons, are responsible for the majority of the weight of matter.
30.
The volume of matter comes mostly from its
Correct Answer
B. Electrons.
Explanation
The volume of matter comes mostly from its electrons. Electrons are negatively charged particles that orbit around the nucleus of an atom. They have a much smaller mass compared to protons and neutrons, but they occupy a larger space due to their high energy levels. The volume of an atom is mainly determined by the electron cloud, which extends far beyond the size of the nucleus. Therefore, the presence and arrangement of electrons contribute significantly to the overall volume of matter.
31.
The chemical properties of matter come mostly from its
Correct Answer
B. Electrons.
Explanation
The chemical properties of matter come mostly from its electrons. Electrons are negatively charged particles that orbit around the nucleus of an atom. They are involved in chemical reactions and determine how atoms interact with each other. The number and arrangement of electrons in an atom's outer shell determine its reactivity and ability to form chemical bonds. Protons and neutrons, on the other hand, are located in the nucleus and primarily contribute to the mass and stability of the atom, rather than its chemical properties.
32.
Compared to the mass of a hydrogen atom, the mass of an oxygen atom is
Correct Answer
C. 16 times as great.
Explanation
The mass of an oxygen atom is 16 times as great as the mass of a hydrogen atom. This means that the mass of an oxygen atom is 16 times larger than the mass of a hydrogen atom.
33.
In a closed bottle are a certain number of hydrogen molecules. In an identical closed bottle at the same temperature and internal pressure are a certain number of nitrogen molecules. The bottle with the greater number of molecules is the one containing
Correct Answer
C. Both the same
Explanation
The number of molecules in a closed bottle is determined by the volume and the temperature. Since both bottles are identical in terms of temperature and internal pressure, it can be inferred that the number of molecules in each bottle is the same. Therefore, the correct answer is "both the same".
34.
A positron orbiting an antiproton would make up an atom of
Correct Answer
D. Anti-hydrogen.
Explanation
When a positron, which is a positively charged electron, orbits an antiproton, which is a negatively charged proton, they form an atom of anti-hydrogen. This is because the positron and antiproton have opposite charges, so they are attracted to each other and can form a stable atom. Positronium is a short-lived atom consisting of an electron and a positron, not an antiproton. Unobtainium and anti-helium are not valid terms for this scenario. Therefore, the correct answer is anti-hydrogen.
35.
If a gram of antimatter meets a kilogram of matter, the amount of mass to survive is
Correct Answer
B. 999 grams.
Explanation
When a gram of antimatter meets a kilogram of matter, they annihilate each other, resulting in the complete conversion of their mass into energy. According to the principle of conservation of mass and energy, the total mass before and after the annihilation should remain the same. Therefore, the amount of mass that survives after the annihilation is equal to the mass of matter that was present before the interaction, which is 999 grams.
36.
What is the molecular mass of a water molecule?
Correct Answer
D. 18 amu
Explanation
The molecular mass of a water molecule is 18 amu. The molecular mass is calculated by adding up the atomic masses of all the atoms in the molecule. In the case of water, there are two hydrogen atoms with an atomic mass of 1 amu each, and one oxygen atom with an atomic mass of 16 amu. Adding these up gives a total molecular mass of 18 amu.
37.
If two protons are removed from an oxygen nucleus, the result is
Correct Answer
B. Carbon.
Explanation
When two protons are removed from an oxygen nucleus, the atomic number decreases by 2, resulting in a new element. Carbon has an atomic number of 6, which is 2 less than oxygen's atomic number of 8. Therefore, the correct answer is carbon.
38.
To change mercury into gold, a pair of protons must be
Correct Answer
E. None of the above is true.
Explanation
Changing mercury into gold involves a process called transmutation, which is not possible by simply removing or adding protons to the nucleus. Transmutation typically requires changing the number of protons and neutrons in the nucleus, which cannot be achieved by removing or adding just a pair of protons. Therefore, none of the above options are true.
39.
If two protons are added to an oxygen nucleus, the result is
Correct Answer
C. Neon.
Explanation
When two protons are added to an oxygen nucleus, the resulting element will have an atomic number of 10, which corresponds to neon. Neon is a noble gas with a full outer electron shell, making it stable and unreactive. Therefore, adding two protons to an oxygen nucleus transforms it into neon.
40.
If a pair of helium nuclei are fused together, the result is
Correct Answer
C. Beryllium.
Explanation
When a pair of helium nuclei are fused together, the result is the formation of a beryllium nucleus. This is because the fusion of two helium nuclei, each consisting of two protons and two neutrons, leads to the combination of four protons and four neutrons, which is the atomic structure of beryllium.
41.
If one neutron is added to a helium nucleus, the result is
Correct Answer
E. Helium
Explanation
If one neutron is added to a helium nucleus, the result is still a helium nucleus. Adding a neutron does not change the identity of the element, only the mass number. So, the correct answer is helium.
42.
How many protons should be added to the nuclei of oxygen atoms so the resulting gas will glow red when there is an electric current through it?
Correct Answer
B. 2
Explanation
To make a gas glow red when an electric current passes through it, the gas needs to be excited and emit red light. This can be achieved by adding electrons to the gas atoms, not protons. The addition of electrons to the gas atoms will cause them to move to higher energy levels. When these electrons return to their original energy levels, they release energy in the form of red light. Therefore, the statement that protons need to be added is incorrect.
43.
Which of these atoms has the greatest amount of electrical charge in its nucleus?
Correct Answer
E. Uranium
Explanation
Uranium has the greatest amount of electrical charge in its nucleus because it has the highest atomic number among the given options. The atomic number represents the number of protons in an atom's nucleus, and protons carry positive electrical charge. Therefore, as the atomic number increases, the number of protons and the positive charge in the nucleus also increase. Uranium, with an atomic number of 92, has more protons and thus a greater amount of electrical charge in its nucleus compared to helium, carbon, iron, and gold.
44.
Which of these atoms has the greatest number of electrons?
Correct Answer
E. Uranium
Explanation
Uranium has the greatest number of electrons among the given atoms. Uranium is an element with atomic number 92, which means it has 92 electrons. Helium has 2 electrons, carbon has 6 electrons, iron has 26 electrons, and gold has 79 electrons. Therefore, uranium has the highest number of electrons compared to the other atoms listed.