1.
A chemical can be defined as...
Correct Answer
C. Any substance that has a definite composition
Explanation
The correct answer is "any substance that has a definite composition." This definition accurately describes a chemical because chemicals are substances that are made up of specific elements or compounds in fixed proportions. This definition distinguishes chemicals from other substances, such as mixtures or solutions, which may not have a fixed composition.
2.
Inorganic chemistry is the study of...
Correct Answer
A. Non-carbon related compounds
Explanation
Inorganic chemistry is the study of non-carbon related compounds. This field focuses on understanding and analyzing the properties, structures, and behaviors of elements and compounds that do not contain carbon. It involves studying various elements, their reactions, and their compounds, excluding those that are primarily carbon-based. Inorganic chemistry plays a crucial role in areas such as materials science, medicine, environmental science, and industry, providing insights into the behavior and applications of non-carbon compounds.
3.
Biochemisty is the study of...
Correct Answer
B. The chemistry of living things
Explanation
Biochemistry is the branch of science that focuses on the chemical processes and substances that occur within living organisms. It involves studying the structure, composition, and function of biological molecules such as proteins, carbohydrates, lipids, and nucleic acids. By understanding the chemistry of living things, biochemists can explore how these molecules interact and contribute to various biological processes, including metabolism, cellular signaling, and genetic information transfer.
4.
Organic chemistry is the study of...
Correct Answer
D. Carbon-containing compounds
Explanation
Organic chemistry is the study of carbon-containing compounds. This branch of chemistry focuses on the structure, properties, composition, reactions, and synthesis of organic compounds, which are compounds that contain carbon atoms. Carbon is unique in its ability to form a wide variety of compounds due to its ability to form strong covalent bonds with other elements. Understanding organic chemistry is crucial in fields such as medicine, biochemistry, pharmacology, and materials science, as it helps in the development of new drugs, understanding biological processes, and creating new materials with desired properties.
5.
Technological development often occurs...
Correct Answer
A. By accident
Explanation
Technological development often occurs by accident because many discoveries and inventions have been made unintentionally while researchers were pursuing other objectives. Serendipity plays a significant role in technological advancements, where unexpected outcomes or unintended consequences lead to new discoveries and innovations. Examples include the discovery of penicillin, the microwave oven, and the Post-it note. These breakthroughs were not the initial goal of the researchers but were accidental discoveries that revolutionized various industries and improved our lives.
6.
Basic research is usually performed...
Correct Answer
C. To gain knowledge
Explanation
Basic research is typically conducted to gain knowledge. This type of research focuses on exploring and understanding fundamental concepts and principles, without any immediate practical application or specific problem-solving objective in mind. It aims to expand the existing knowledge base, provide a foundation for further research, and contribute to the overall understanding of a particular field or topic. Basic research often forms the basis for applied research, which is focused on developing new products or solving specific problems.
7.
Applied research is usually performed...
Correct Answer
A. To solve a particular problem
Explanation
Applied research is usually performed to solve a particular problem. This type of research focuses on practical applications and seeks to address real-world issues or challenges. It involves utilizing existing knowledge and techniques to find solutions or develop new approaches that can be directly applied to the problem at hand. The goal is to generate practical outcomes and improve the current situation by providing actionable insights or innovations.
8.
Which of the following is an extensive property of matter?
Correct Answer
C. Volume
Explanation
Volume is an extensive property of matter because it depends on the amount of substance present. It is a measure of the space occupied by a substance and can change with the quantity of matter. For example, if you have two containers of water, one with a larger volume than the other, it means that the container with the larger volume contains more water. Extensive properties, like volume, are additive and can be directly proportional to the amount of substance present.
9.
Which of the following is an intensive property of matter?
Correct Answer
B. Density
Explanation
Density is an intensive property of matter because it does not depend on the amount of substance present. It is a ratio of mass to volume, meaning that it remains constant regardless of the size or amount of the substance. This property is useful for identifying and characterizing different materials, as it provides information about how closely packed the particles are within a given volume.
10.
The two most important properties of all matter are...
Correct Answer
B. Taking up space and having mass
Explanation
The correct answer is "taking up space and having mass." These two properties are fundamental to all matter. Taking up space refers to the fact that matter occupies a certain volume or physical space. Having mass means that matter has a measurable amount of substance or material. These properties are universal and apply to all forms of matter, whether solid, liquid, or gas.
11.
An atom is...
Correct Answer
A. The smallest unit of matter that maintains its chemical identity
Explanation
An atom is the smallest unit of matter that maintains its chemical identity because it consists of a nucleus containing protons and neutrons, surrounded by electrons. It cannot be broken down into smaller particles without losing its unique properties. Atoms combine to form compounds, but they themselves are not compounds. Not all atoms are made of carbon, as there are many different elements. Electrons are subatomic particles and are smaller than atoms.
12.
A compound is...
Correct Answer
B. A substance, made up of two or more atoms that are chemically bonded, that can be broken down into simpler, stable substances
Explanation
A compound is a substance that is made up of two or more atoms that are chemically bonded together. It can be broken down into simpler, stable substances through chemical reactions. This means that compounds can be decomposed into their constituent elements or other compounds. Examples of compounds include water (H2O), carbon dioxide (CO2), and sodium chloride (NaCl). Compounds have specific chemical properties that are different from the elements they are composed of, and they often have unique physical properties as well.
13.
A measure of the quantity of matter is...
Correct Answer
D. Mass
Explanation
Mass is a measure of the quantity of matter in an object. It represents the amount of material present in an object and is often measured in units such as kilograms or pounds. Mass is different from weight, as weight is the force exerted on an object due to gravity. Density is a measure of how much mass is contained within a given volume, and volume is the amount of space occupied by an object. Therefore, the correct answer for this question is mass.
14.
Matter includes all of the following except
Correct Answer
B. Light
Explanation
Matter refers to anything that has mass and occupies space. Among the given options, air, smoke, and water vapor are all examples of matter as they have mass and occupy space. However, light does not have mass and does not occupy space, so it is not considered matter. Hence, light is the correct answer.
15.
A true statement about mass is that...
Correct Answer
D. Mass is determined by comparing the mass of an object with a set of standard masses that are art of a balance
Explanation
The correct answer is that mass is determined by comparing the mass of an object with a set of standard masses that are part of a balance. This means that mass is typically measured by comparing the unknown mass to a known mass using a balance. By comparing the two masses, the unknown mass can be determined. This method is commonly used in laboratories and scientific settings to accurately measure the mass of objects.
16.
Which of the following is not a physical change?
Correct Answer
D. Burning
Explanation
Burning is not a physical change because it involves a chemical reaction where the substance reacts with oxygen to produce new substances. In a physical change, the substance remains the same, only its physical properties, such as shape or state, may change. Grinding, cutting, and boiling are physical changes because they only alter the physical properties of the substance without changing its chemical composition.
17.
Which of the following is not a chemical change?
Correct Answer
C. Melting
Explanation
Melting is not a chemical change because it is a physical change. In melting, a substance changes from a solid to a liquid state due to the increase in temperature, but the chemical composition of the substance remains the same. No new substances are formed during melting, unlike in rusting, igniting, and burning where chemical reactions occur and new substances are produced.
18.
A chemical change occurs when...
Correct Answer
D. A leaf changes color in the fall
Explanation
A leaf changing color in the fall is an example of a chemical change because it involves a transformation in the leaf's pigments. During this process, chlorophyll, which gives leaves their green color, breaks down, and other pigments such as carotenoids and anthocyanins become more visible, causing the leaf to change colors. This change in color is a result of chemical reactions occurring within the leaf.
19.
A physical change occurs when a...
Correct Answer
D. Glue gun melts a glue stick
Explanation
When a glue gun melts a glue stick, it is an example of a physical change. This is because the glue stick undergoes a change in its physical state, from solid to liquid, due to the application of heat from the glue gun. The chemical composition of the glue stick remains the same, only its physical properties are altered.
20.
Noble Gases are in Group 18, and are best known because they are...
Correct Answer
A. Unreactive
Explanation
Noble Gases are in Group 18 of the periodic table, which is also known as the "noble gas group." They are called noble gases because they have a full outer electron shell, making them stable and unreactive. This means that noble gases do not easily form chemical bonds with other elements, making them highly unreactive. As a result, they are often used in applications where a lack of reactivity is desired, such as in lighting, lasers, and as a protective gas in certain industrial processes.
21.
Nitrogen monoxide and oxygen, both colorless gases, form a red-brown gas when mixed. Nitrogen monoxide and oxygen are called the...
Correct Answer
D. Reactants
Explanation
When nitrogen monoxide and oxygen, both colorless gases, are mixed, they form a red-brown gas. This indicates that a chemical reaction is taking place. In a chemical reaction, the substances that react with each other are called reactants. Therefore, nitrogen monoxide and oxygen are the reactants in this reaction.
22.
A state of matter in which a material has no definite shape but has a definite volume is the ___ state?
Correct Answer
B. Liquid
Explanation
A state of matter in which a material has no definite shape but has a definite volume is referred to as a liquid. Liquids are characterized by their ability to flow and take the shape of their container, while still maintaining a fixed volume. This is in contrast to gases, which have neither a definite shape nor volume, and solids, which have both a definite shape and volume. Plasma, on the other hand, is a state of matter in which the material is ionized and consists of charged particles.
23.
Under ordinary conditions of temperature and pressure, the particles in a gas are...
Correct Answer
B. Very far from one another
Explanation
The correct answer is "very far from one another" because under ordinary conditions of temperature and pressure, the particles in a gas have high kinetic energy which causes them to move rapidly and randomly. This movement leads to the particles being spread out and occupying a large volume, resulting in them being very far from one another.
24.
The liquid state of matter can be described as...
Correct Answer
D. Having definite volume but not definite shape
Explanation
The liquid state of matter is characterized by having a definite volume, meaning it takes up a specific amount of space, but it does not have a definite shape. Unlike solids, which have a fixed shape, liquids can flow and take the shape of their container. Therefore, the correct answer is "having definite volume but not definite shape."
25.
A solid substance is...
Correct Answer
C. Always the same shape regardless of its container
Explanation
A solid substance is always the same shape regardless of its container because solids have a fixed shape and volume. The particles in a solid are tightly packed and have strong intermolecular forces that hold them in a fixed position. This means that regardless of the shape or size of the container, the solid will maintain its own shape and not conform to the shape of the container.
26.
Plasma is the fourth state of matter. In the plasma state...
Correct Answer
B. Atoms lose electrons
Explanation
In the plasma state, atoms lose electrons. Plasma is a highly ionized gas where the atoms have been stripped of some or all of their electrons. This results in a mixture of free electrons and positively charged ions. The process of atoms losing electrons is known as ionization. In the plasma state, the atoms become highly energized and the loss of electrons allows them to carry an electric charge. This characteristic of plasma makes it highly conductive and responsive to electric and magnetic fields.
27.
What happens to the energy in a substance when it changes state?
Correct Answer
C. It changes form, but it is neither destroyed nor increased
Explanation
When a substance changes state, such as from solid to liquid or from liquid to gas, the energy in the substance does not get destroyed or increased. Instead, it changes form. The energy is converted from one form, such as thermal energy, to another form, such as potential energy or kinetic energy. This conversion allows the substance to transition from one state to another without any loss or gain of energy.
28.
The only pure substance listed below is...
Correct Answer
C. Vitamin C (ascorbic acid)
Explanation
Vitamin C (ascorbic acid) is the only pure substance listed because it is a single chemical compound with a specific molecular structure. Bread dough, vinegar, and seawater are all mixtures that contain multiple substances. Bread dough is a mixture of flour, water, yeast, and other ingredients. Vinegar is a mixture of acetic acid and water. Seawater is a mixture of various salts, minerals, and other substances dissolved in water. Only vitamin C (ascorbic acid) is a pure substance with a uniform composition.
29.
A mixture is...
Correct Answer
C. A blend of any two or more kinds of matter, as long as each maintains its own unique properties
Explanation
A mixture is a blend of any two or more kinds of matter, as long as each maintains its own unique properties. This means that in a mixture, different substances are combined together, but they do not chemically bond with each other. Each component of the mixture retains its own distinct characteristics and can be separated from the mixture through physical means, such as filtration or evaporation.
30.
If a mixture is uniform in composition, it is said to be...
Correct Answer
A. Homogeneous
Explanation
A mixture that is uniform in composition is called homogeneous. This means that the components of the mixture are evenly distributed throughout, resulting in a consistent composition and appearance. In contrast, a heterogeneous mixture would have visible differences in composition, such as separate layers or distinct regions. The term "chemically bonded" refers to the formation of chemical bonds between atoms, which is not relevant to the concept of mixtures. Lastly, a compound is a substance formed by the chemical combination of two or more elements, and it is distinct from a mixture.
31.
If a mixture is not uniform throughout, it is called...
Correct Answer
B. Heterogeneous
Explanation
A mixture that is not uniform throughout is called heterogeneous. This means that the components in the mixture are not evenly distributed and can be easily distinguished. In a heterogeneous mixture, you can visually identify different substances or phases within the mixture. This is in contrast to a homogeneous mixture, where the components are evenly mixed and cannot be easily distinguished. Chemically bonded refers to substances that are chemically combined, while a solution specifically refers to a homogeneous mixture of two or more substances.
32.
Which of the following is an example of a heterogeneous mixture?
Correct Answer
C. Granite
Explanation
Granite is an example of a heterogeneous mixture because it is composed of different substances that are not evenly distributed throughout the mixture. It is made up of various minerals, such as quartz, feldspar, and mica, which can be easily distinguished by the naked eye. This non-uniform composition and visible presence of different components make granite a heterogeneous mixture.
33.
A homogeneous mixture is also called...
Correct Answer
C. A solution
Explanation
A homogeneous mixture is also called a solution because it is a uniform mixture where the different components are evenly distributed at a molecular level. In a solution, the solute particles are dispersed and completely mixed with the solvent particles, resulting in a homogeneous appearance throughout the mixture. This is different from a compound, which is a substance formed by the chemical bonding of two or more elements. Therefore, the term "a solution" accurately describes a homogeneous mixture.
34.
Which of the following is an example of a homogeneous mixture?
Correct Answer
A. Air
Explanation
Air is an example of a homogeneous mixture because it is composed of a combination of gases, such as nitrogen, oxygen, carbon dioxide, and others, that are uniformly distributed throughout. This means that the composition of air is the same throughout, regardless of where it is sampled from.
35.
All known chemical elements are organized into groups based on similar chemical properties in the...
Correct Answer
D. None of the above
36.
The vertical columns on the periodic table are called...
Correct Answer
C. Groups
Explanation
The vertical columns on the periodic table are called "groups". These groups represent elements with similar chemical properties and shared electron configurations. Each group contains elements that have the same number of valence electrons, which determines their reactivity and bonding behavior. The groups are numbered from 1 to 18, and elements within the same group tend to exhibit similar trends in their physical and chemical properties.
37.
The horizontal rows on the periodic table are called...
Correct Answer
D. Periods
Explanation
The horizontal rows on the periodic table are called periods. They represent the different energy levels or shells that electrons can occupy in an atom. Each period corresponds to a specific number of electron shells, with the first period having only one shell and subsequent periods having more shells as the atomic number increases. The periods help to organize the elements based on their electron configurations and properties.
38.
It is easy to determine whether a substance is a metal if the substance is...
Correct Answer
D. A good electrical and heat conductor
Explanation
A substance that is a good electrical and heat conductor is likely to be a metal because metals generally have high electrical and thermal conductivity. This is because the electrons in metals are loosely held and can move freely, allowing for the easy flow of electricity and heat. Therefore, if a substance exhibits these properties, it is likely to be a metal.
39.
A nonmetal is usually...
Correct Answer
A. Brittle
Explanation
A nonmetal is usually brittle because nonmetals have a tendency to form covalent bonds, which involve the sharing of electrons between atoms. This results in a relatively weak bond compared to the metallic or ionic bonds found in metals. As a result, nonmetals are unable to withstand deformation and are prone to breaking or shattering when subjected to stress.
40.
Metalloids are often...
Correct Answer
B. Semiconductors
Explanation
Metalloids are elements that have properties of both metals and nonmetals. One of the main characteristics of metalloids is their ability to conduct electricity, but not as efficiently as metals. This property makes them useful as semiconductors in various electronic devices. Semiconductors can be used to control the flow of electrical current, making them essential for the functioning of devices like transistors and diodes. Therefore, the correct answer is "semiconductors".