Daniel P. is an experienced STEM club teacher with 11 years of urban teaching experience. He holds a MSEd in Science Education from The City College of New York and a BA in History from Binghamton University. He is committed to enhancing student education, using his expertise in curriculum design, differentiated instruction, and Google Classroom.
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Get ready to test your knowledge with our engaging Science Quiz for Grade 9! This detailed quiz is designed to challenge students on key concepts covered in the Grade 9 science curriculum. From biology and chemistry to physics and environmental science, this quiz encompasses a wide range of topics that are essential for understanding the fundamentals of science.
Perfect for both classroom settings and self-assessment, our science quiz for grade 9 includes multiple-choice questions that not only test your knowledge but also help reinforce learning. Each question is followed by an answer key, allowing students to check their understanding Read moreand learn from any mistakes. Take the challenge and see how much you know about the exciting world of science!
Science Quiz for Grade 9 With Answers Questions and Answers
1.
When is an atom considered stable?
A.
When it has a full outer valence shell.
B.
When it has the same amount of electrons as protons.
C.
When it has no neutrons.
D.
When it has an odd number of valence electrons.
Correct Answer
A. When it has a full outer valence shell.
Explanation An atom is considered stable when it has a full outer valence shell of electrons. This configuration makes the atom less likely to react with other atoms, as it has achieved a stable, low-energy state. Typically, atoms achieve stability by gaining, losing, or sharing electrons to complete their outer shell, following the octet rule for most elements. The other options do not necessarily indicate stability.
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2.
An ion is formed when an atom loses/gains an electron.
A.
True
B.
False
Correct Answer
A. True
Explanation An ion is formed when an atom loses or gains an electron because the loss or gain of an electron creates an imbalance between the number of protons and electrons in the atom. If an atom loses an electron, it becomes positively charged and forms a cation. If an atom gains an electron, it becomes negatively charged and forms an anion. Therefore, the statement is true.
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3.
A molecule is the same thing as an atom.
A.
True
B.
False
Correct Answer
B. False
Explanation False. A molecule is not the same as an atom. An atom is the basic unit of an element, composed of a nucleus containing protons and neutrons, with electrons orbiting around. In contrast, a molecule consists of two or more atoms chemically bonded together. Molecules can be composed of the same or different types of atoms.
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4.
How many atoms are in Ca(NO3)2?
A.
Ca-1 N-6 O-2
B.
Ca-1 N-2 O-6
C.
Ca-6 N-2 O-1
D.
Ca-2 N-1 O-6
Correct Answer
B. Ca-1 N-2 O-6
Explanation The correct answer is Ca-1 N-2 O-6. There is one calcium atom (Ca), two nitrogen atoms (N), and six oxygen atoms (O) in the compound Ca(NO3)2. The subscript numbers indicate the number of each type of atom present in the molecule. The number of nitrogen atoms and oxygen atoms inside the parentheses is multiplied by 2 due to the 2 outside the parentheses.
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5.
What does not necessarily indicate a chemical change has occurred?
A.
When a change of color
B.
When a heat is produced
C.
When a smell is produced
D.
When a light is produced
E.
When a gas is produced
Correct Answer
C. When a smell is produced
Explanation The production of smell does not necessarily indicate a chemical change because it can also occur in physical changes. Smells can be produced when substances evaporate or when they are physically broken down, without any chemical reactions taking place. Therefore, the production of smell alone is not sufficient evidence to indicate a chemical change.
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6.
What is the equation for photosynthesis?
A.
H2O+oxygen (light+chlorophyll) = CO2+glucose
B.
H2O+CO2 (light+chlorophyll) = oxygen+glucose
C.
CO2+light (chlorophyll +water) = H2O+oxygen
Correct Answer
B. H2O+CO2 (light+chloropHyll) = oxygen+glucose
Explanation The equation for photosynthesis is H2O+CO2 (light+chlorophyll) = oxygen+glucose. This equation represents the process by which plants and some other organisms convert carbon dioxide and water into oxygen and glucose, using sunlight and chlorophyll as catalysts.
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7.
What does photosynthesis provide us with?
A.
Energy
B.
Water
C.
Oxygen
D.
Glucose
E.
Light
Correct Answer(s)
A. Energy C. Oxygen D. Glucose
Explanation Photosynthesis provides us with oxygen and glucose.
Oxygen: During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) and convert them into glucose and oxygen. The oxygen is released into the atmosphere, which is essential for the survival of most organisms on Earth, including humans.
Glucose: The glucose produced by plants during photosynthesis is a source of energy for many organisms. Herbivores eat plants to get this energy, and carnivores eat herbivores, thus the energy from photosynthesis flows through the food chain.
While photosynthesis does require light and water as inputs, it does not provide these as outputs. Therefore, “light” and “water” are not correct answers. As for “energy”, while it’s true that the glucose produced in photosynthesis stores energy that can be used by other organisms, the process itself does provide energy in a form that can be used by humans or animals.
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8.
What is not an interaction among ecosystems?
A.
Competition
B.
Mutualism
C.
Equilibrium
D.
Predation
Correct Answer
C. Equilibrium
Explanation Equilibrium is not an interaction among ecosystems. Equilibrium refers to a state of balance or stability within an ecosystem, where the population sizes and resources remain relatively constant over time. It does not involve any direct interaction between different ecosystems or organisms. In contrast, competition, mutualism, and predation are all types of interactions that occur between organisms in different ecosystems, influencing population dynamics and resource utilization.
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9.
Which of the following is not a limiting factor?
A.
Climate extremes
B.
Disease
C.
Predation
D.
Biodiversity
E.
Human disturbances
F.
Competition
Correct Answer
D. Biodiversity
Explanation Biodiversity is not a limiting factor because it refers to the variety of different species in an ecosystem, and does not directly limit the growth or survival of any particular species. Climate extremes, disease, predation, human disturbances, and competition can all limit the population size or distribution of certain species, but biodiversity itself is not a limiting factor in this context.
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10.
_________ is a measure of how many species live in an ecosystem.
Correct Answer Biodiversity
Explanation Biodiversity is a measure of how many different species are present in a particular ecosystem. It quantifies the diversity of species within that ecosystem, indicating the number of different organisms that coexist in a given area. This measure does not take into account the abundance or population size of each species, but rather focuses on the total number of distinct species present.
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11.
Bioamplification/biomagnification is when toxin levels increase at each trophic level.
A.
True
B.
False
Correct Answer
A. True
Explanation Bioamplification, also known as biomagnification, is a process in which the concentration of toxins increases as they move up the food chain. This occurs because organisms at higher trophic levels consume a larger quantity of prey or plants that may contain toxins, resulting in the accumulation of these toxins in their bodies. As a result, the toxin levels become higher at each successive trophic level. Therefore, the statement "Bioamplification/biomagnification is when toxin levels get higher at each trophic level" is true.
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12.
What is it called when toxins build up in a single organism?
A.
Bioamplification
B.
Bioaccumulation
C.
Biomagnification
Correct Answer
B. Bioaccumulation
Explanation Bioaccumulation is the process by which toxins gradually accumulate in the tissues of an individual organism over time. This occurs when the organism is exposed to these toxins through its environment or food sources, and is unable to eliminate them at the same rate they are being absorbed. As a result, the concentration of toxins in the organism's body increases, leading to potential harmful effects on its health.
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13.
The order of the planets from closest to the Sun to furthest away is Mars, Venus, Earth, Mercury, Saturn, Uranus, and Neptune.
A.
True
B.
False
Correct Answer
B. False
Explanation The correct order of the planets is: Mercury, Venus, Earth, Mars, Jupiter (not included in the question), Saturn, Uranus and Neptune
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14.
The Milky Way is a barred spiral galaxy.
A.
True
B.
False
Correct Answer
A. True
Explanation The Milky Way is a barred spiral galaxy. This means that it has a central bar-shaped structure composed of stars, around which the spiral arms of the galaxy extend. The Milky Way's classification as a barred spiral galaxy has been confirmed through various astronomical observations and research (ASEAN) .
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15.
Which is the largest type of galaxy in the universe?
A.
Spiral galaxy
B.
Elliptical galaxy
C.
Irregular galaxy
D.
Dwarf galaxy
Correct Answer
B. Elliptical galaxy
Explanation The largest type of galaxy in the universe is the elliptical galaxy. These galaxies are characterized by their smooth, oval or elliptical shape and typically contain older stars with less interstellar gas and dust, resulting in less active star formation. Elliptical galaxies can vary in size, with some being small and others being massive. They are often found in regions of high galaxy density, such as galaxy clusters, and are one of the main classifications of galaxies based on their shape and structure.
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16.
A star is made of hydrogen and helium.
A.
True
B.
False
Correct Answer
A. True
Explanation A star is made up of hydrogen and helium because in the core of a star, nuclear fusion reactions occur where hydrogen atoms combine to form helium, releasing a tremendous amount of energy in the process. This energy is what makes the star shine and produce heat and light.
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17.
The Moon is not a satellite.
A.
True
B.
False
Correct Answer
B. False
Explanation The Moon is indeed a natural satellite. A satellite is an object that orbits a planet. The Moon orbits the Earth, making it a natural satellite. It is Earth's only natural satellite and plays a crucial role in influencing tides and stabilizing Earth's rotation.
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18.
When can a circumpolar constellation be seen?
A.
Once a year
B.
All year round
C.
Never
D.
Once in every 100 years
Correct Answer
B. All year round
Explanation A circumpolar constellation can be seen all year round. Circumpolar constellations are located near the celestial pole, either the North or South Pole, and appear to circle around it. As a result, they never dip below the horizon and are visible throughout the year. This is in contrast to other constellations that rise and set with the rotation of the Earth and may not be visible at certain times of the year.
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19.
What are some circumpolar constellations? (more than one)
A.
Draco
B.
Aquarius
C.
Ursa Major
D.
Ursa Minor
E.
Leo
Correct Answer(s)
A. Draco C. Ursa Major D. Ursa Minor
Explanation The circumpolar constellations are those that never set below the horizon and can be seen year-round in the northern hemisphere. Draco, Ursa Major, and the Ursa Minor (Little Dipper ) are all examples of circumpolar constellations. These constellations are visible throughout the night and are easily recognizable due to their prominent stars and distinctive shapes. Aquarius and Leo, on the other hand, are not circumpolar constellations, as they are set below the horizon at certain times of the year.
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20.
The longest day of the year in the Northern Hemisphere is ________
Correct Answer(s) june 21, June 21, 21 June, 21 june, June 21st
Explanation The longest day of the year in the Northern Hemisphere is the summer solstice, typically occurring around June 21st each year. During this time, the Northern Hemisphere experiences the longest period of daylight and the shortest night of the year.
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21.
Static electricity only happens with conductors.
A.
True
B.
False
Correct Answer
B. False
Explanation False. Static electricity can occur with both conductors and insulators. While conductors allow the flow of electrons, insulators resist the flow. In static electricity, electrons can accumulate on the surface of insulators, creating a charge imbalance. This phenomenon is observed in various materials, not limited to conductors, as static charges can build up and discharge between objects with different electrical potentials.
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22.
What does an atom become when it gains an electron?
A.
Cation
B.
Anion
C.
Onion
D.
None of the above
Correct Answer
B. Anion
Explanation When an atom gains an electron, it becomes an anion. An anion is a negatively charged ion because it now has more electrons than protons. This results in an overall negative charge for the atom. A cation, on the other hand, is a positively charged ion formed when an atom loses an electron. "Onion" is not a term used in chemistry to describe the result of an atom gaining an electron.
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23.
In a circuit, from which end do the electrons flow to the positive end?
A.
Positive
B.
Negative
C.
Neutral
Correct Answer
B. Negative
Explanation In an electrical circuit, electrons flow from the negative end (cathode) to the positive end (anode). This flow is due to the attraction between negatively charged electrons and the positively charged end of the circuit. This movement of electrons constitutes the electric current.
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24.
Which process describes the change of a substance from a solid state directly to a gaseous state without passing through the liquid state?
A.
Evaporation
B.
Condensation
C.
Sublimation
D.
Deposition
Correct Answer
C. Sublimation
Explanation Sublimation is the process where a substance changes directly from a solid to a gaseous state without passing through the liquid state. This occurs when the molecules of the solid gain enough energy to break free from their fixed positions and enter the gaseous phase. An example of sublimation is dry ice, which is solid carbon dioxide that changes directly into carbon dioxide gas when it warms up.
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25.
Which is not a method of electrical discharge?
A.
At a point
B.
A spark
C.
Friction
D.
Moisture
Correct Answer
C. Friction
Explanation Friction is not a method of electrical discharge. Discharging refers to the process of releasing or removing an electrical charge. The options "at a point," "a spark," and "moisture" are all methods that can cause discharging. However, friction does not directly involve the release or removal of electrical charge. Instead, friction refers to the force that occurs when two surfaces rub against each other, which can generate static electricity but is not a method of discharging it.
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26.
A current is the only form of electricity.
A.
True
B.
False
Correct Answer
B. False
Explanation False. While electric current is a common form of electricity involving the flow of charged particles, it's not the only form. Static electricity, for instance, involves the imbalance of charges at rest. Additionally, there is alternating current (AC) and direct current (DC). AC periodically changes direction, while DC flows in one direction. Various phenomena and technologies encompass different forms of electrical activity.
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27.
What is not a method of creating static electricity?
A.
Friction
B.
Lightning
C.
Contact
D.
Induction
Correct Answer
B. Lightning
Explanation Friction, contact, and induction are all methods of creating static electricity. When two objects rub against each other, like rubbing a balloon on your head, friction occurs and creates static electricity. Contact occurs when a charged object comes into direct contact with a neutral object, causing the neutral object to become charged. Induction involves bringing a charged object close to a neutral object, causing a separation of charges and creating static electricity. Lightning, on the other hand, is not a method of creating static electricity. It is a natural phenomenon that occurs due to the buildup and discharge of electrical energy in the atmosphere.
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28.
Which of the following best explains the role of mitochondria in eukaryotic cells?
A.
Energy production
B.
Energy storage
C.
Photosynthesis
D.
Protein synthesis
Correct Answer
A. Energy production
Explanation Mitochondria are often referred to as the "powerhouses" of the cell due to their crucial role in energy production. They are membrane-bound organelles found in most eukaryotic cells. The primary function of mitochondria is to generate adenosine triphosphate (ATP) through a process called oxidative phosphorylation, which occurs during cellular respiration. During this process, glucose and oxygen are converted into ATP, carbon dioxide, and water. This energy is vital for various cellular functions, including muscle contraction, nerve impulse propagation, and biosynthesis of macromolecules. Mitochondria also have their own DNA, which is inherited maternally, and they play a significant role in apoptosis, the programmed cell death that is essential for development and homeostasis.
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29.
What is the primary reason for the formation of chemical bonds between atoms?
A.
To achieve chemical balance
B.
To complete the valence shell
C.
To lose electrons
D.
To gain electrons
Correct Answer
B. To complete the valence shell
Explanation Sulfuric acid is a highly corrosive strong mineral acid with the chemical formula H₂SO₄. It consists of two hydrogen atoms, one sulfur atom, and four oxygen atoms. Sulfuric acid is one of the most widely used chemicals in the world and has applications in various industries, including manufacturing fertilizers, refining oil, and treating metals. In laboratories, it serves as a dehydrating agent and is involved in many chemical reactions due to its strong acidic properties. Its production involves the Contact Process, where sulfur dioxide is oxidized to sulfur trioxide, which then reacts with water to produce sulfuric acid. It is important to handle sulfuric acid with care due to its exothermic reaction with water, which can lead to splattering.
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30.
Which of the following laws explains why planets orbit the Sun?
A.
Newton's First Law
B.
Newton's Third Law
C.
Law of Universal Gravitation
D.
Archimedes' Principle
Correct Answer
C. Law of Universal Gravitation
Explanation The melting of ice into water is classified as a physical change because it involves a change in the state of matter without altering the chemical composition of the substance. When ice (solid water) is heated, the thermal energy increases the movement of water molecules, allowing them to overcome the forces that hold them in a rigid structure. As a result, the ice melts into liquid water, which is still H₂O. During this process, no new substances are formed, which is a hallmark of physical changes. The melting point of ice is 0°C (32°F) under standard atmospheric conditions. Understanding this process is fundamental in various scientific fields, including chemistry and environmental science.
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31.
In the periodic table, elements in the same group have similar properties because they have the same number of:
A.
Neutrons
B.
Protons
C.
Valence electrons
D.
Total electrons
Correct Answer
C. Valence electrons
Explanation The ohm (Ω) is the SI unit of electrical resistance, named after the German physicist Georg Simon Ohm. Resistance quantifies how much a material opposes the flow of electric current. In an electrical circuit, components such as resistors create resistance, which affects how much current flows for a given voltage, according to Ohm's Law (V = IR, where V is voltage, I is current, and R is resistance). High resistance means that less current will flow, while low resistance allows more current to pass through. This concept is essential in designing electrical circuits, understanding circuit behavior, and ensuring the safety and efficiency of electrical devices.
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32.
Which of the following best describes the role of enzymes in biological reactions?
A.
Inhibit reactions
B.
Increase activation energy
C.
Act as catalysts
D.
Slow down reactions
Correct Answer
C. Act as catalysts
Explanation The acceleration due to gravity on Earth is approximately 9.8 meters per second squared (m/s²). This value represents the rate at which an object accelerates downward when in free fall, neglecting air resistance. It results from the gravitational force exerted by the Earth on an object, which depends on the object's mass and the distance from the Earth's center. This acceleration is crucial for understanding various phenomena in physics, including projectile motion, the behavior of falling objects, and the dynamics of satellites orbiting the Earth. The concept of gravitational acceleration is also foundational in Einstein's theory of general relativity, which describes gravity as the curvature of spacetime caused by mass.
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33.
What is the main function of the xylem in vascular plants?
A.
Transport water
B.
Transport nutrients
C.
Transport oxygen
D.
Transport sugars
Correct Answer
A. Transport water
Explanation Chloroplasts are specialized organelles found in plant cells and some algae, essential for photosynthesis—the process by which light energy is converted into chemical energy stored in glucose. Chloroplasts contain chlorophyll, the green pigment that captures sunlight, and other pigments that absorb different wavelengths of light. During photosynthesis, carbon dioxide from the atmosphere and water from the soil are used in the presence of sunlight to produce glucose and oxygen. This process is vital for plant growth and energy production and plays a crucial role in the global carbon cycle, as plants are primary producers that form the base of the food chain. Chloroplasts also contain their own DNA, resembling bacterial DNA, which supports the endosymbiotic theory of their origin.
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34.
Which principle explains the buoyant force experienced by objects submerged in a fluid?
A.
Bernoulli’s Principle
B.
Pascal’s Law
C.
Archimedes' Principle
D.
Boyle’s Law
Correct Answer
C. Archimedes' Principle
Explanation Oxygen constitutes approximately 46.6% of the Earth's crust by weight, making it the most abundant element in the crust. It primarily exists in the form of oxides, with silica (SiO₂) being the most prevalent mineral, found in rocks like quartz and granite. Oxygen is essential for the formation of many minerals and compounds and plays a critical role in geological processes. It is also vital for life, as it is a key component of cellular respiration in animals and the process of photosynthesis in plants. The availability of oxygen in the atmosphere, which is produced by photosynthetic organisms, is crucial for sustaining life on Earth.
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35.
Which type of electromagnetic radiation has the shortest wavelength?
A.
Visible light
B.
Ultraviolet
C.
X-rays
D.
Gamma rays
Correct Answer
D. Gamma rays
Explanation A covalent bond is formed when two nonmetal atoms share pairs of electrons to achieve stability. This type of bonding occurs because nonmetals have similar electronegativities, meaning they attract electrons with comparable strength. Sharing electrons allows each atom to attain a full outer electron shell, satisfying the octet rule and leading to a more stable electronic configuration. Covalent bonds can vary in strength and length, depending on the number of shared electron pairs; single, double, and triple bonds represent one, two, and three shared pairs, respectively. Understanding covalent bonding is fundamental in chemistry, as it explains the structure and properties of many organic and inorganic compounds.
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36.
Which process is responsible for the synthesis of glucose in plants?
A.
Glycolysis
B.
Cellular respiration
C.
Fermentation
D.
Photosynthesis
Correct Answer
D. pHotosynthesis
Explanation Newton's third law of motion states that for every action, there is an equal and opposite reaction. This principle is foundational in mechanics and can be observed in numerous everyday situations. For instance, when you push against a wall, the wall pushes back with equal force, even though it does not move. This law explains the interaction between forces and is essential for understanding how objects move in response to applied forces. It is also the basis for rocket propulsion; as a rocket expels gas downward, the equal and opposite reaction propels the rocket upward. Newton's laws of motion are fundamental to classical mechanics, providing a framework for analyzing the motion of objects.
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37.
What is the primary role of nitrogen in the nitrogen cycle?
A.
Supporting life
B.
Component of DNA and proteins
C.
Acts as a greenhouse gas
D.
Source of oxygen
Correct Answer
B. Component of DNA and proteins
Explanation Carbon dioxide (CO₂) is a greenhouse gas that plays a significant role in Earth's climate system. It is produced through natural processes such as respiration, decomposition, and volcanic eruptions, but human activities, particularly the burning of fossil fuels and deforestation, have significantly increased its concentration in the atmosphere. CO₂ traps heat by absorbing infrared radiation, preventing it from escaping back into space, which contributes to the greenhouse effect. This process is crucial for maintaining Earth's temperature but has led to global warming and climate change due to the enhanced greenhouse effect caused by elevated CO₂ levels. Understanding the role of carbon dioxide in climate change is essential for addressing environmental issues and implementing sustainable practices.
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38.
What phenomenon occurs when the Earth passes directly between the Sun and the Moon?
A.
Solar eclipse
B.
Lunar eclipse
C.
Planetary conjunction
D.
Nebula
Correct Answer
B. Lunar eclipse
Explanation A lunar eclipse occurs when the Earth passes between the Sun and the Moon, casting a shadow on the Moon, which can only happen during a full moon. There are three types of lunar eclipses: total, partial, and penumbral. In a total lunar eclipse, the entire Moon moves through the Earth's darkest shadow (umbra), often taking on a reddish hue known as a "Blood Moon." A partial lunar eclipse occurs when only a portion of the Moon enters the umbra, while a penumbral lunar eclipse is when the Moon passes through the Earth's lighter outer shadow (penumbra), resulting in a subtle shading. Unlike solar eclipses, which are viewable from specific locations, lunar eclipses can be seen from anywhere on the night side of the Earth, making them widely accessible for observation.
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39.
What is the most abundant gas in Earth's atmosphere?
A.
Oxygen
B.
Carbon dioxide
C.
Nitrogen
D.
Hydrogen
Correct Answer
C. Nitrogen
Explanation Nitrogen makes up about 78% of the Earth's atmosphere, while oxygen accounts for approximately 21%. The remaining 1% consists of other gases, including argon, carbon dioxide, neon, and trace amounts of other gases. Nitrogen is a key component of the atmosphere, and while it is relatively inert and does not easily react with other substances, it plays a crucial role in various biological and chemical processes, such as the nitrogen cycle, which is essential for life on Earth. Oxygen is vital for respiration in many living organisms, but it is not the most abundant gas. Carbon dioxide is present in much smaller quantities, primarily as a result of natural processes and human activities, and hydrogen is also found in trace amounts in the atmosphere.
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40.
Which of the following best describes the law of conservation of mass?
A.
Mass can be created or destroyed in a chemical reaction.
B.
The total mass of reactants equals the total mass of products in a closed system.
C.
The mass of an object increases when heated.
D.
Mass can change forms but cannot be measured.
Correct Answer
B. The total mass of reactants equals the total mass of products in a closed system.
Explanation The law of conservation of mass, formulated by Antoine Lavoisier in the late 18th century, states that in a chemical reaction, matter is neither created nor destroyed. This principle implies that the total mass of the substances involved in a chemical reaction remains constant, provided that the system is closed and no mass enters or leaves the system. Therefore, the mass of the reactants (the starting materials) must equal the mass of the products (the substances formed) after the reaction has occurred.
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Daniel P |MSEd (Science Education)|
Science Teacher
Daniel P. is an experienced STEM club teacher with 11 years of urban teaching experience. He holds a MSEd in Science Education from The City College of New York and a BA in History from Binghamton University. He is committed to enhancing student education, using his expertise in curriculum design, differentiated instruction, and Google Classroom.
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