1.
Which of the following is a physical property of an element?
Correct Answer
A. Color
Explanation
Color is a physical property of an element because it is an observable characteristic that can be determined without changing the chemical composition of the substance. Different elements have different colors, which can be used to identify and distinguish them.
2.
During a chemical change, the form of a substance is altered, but not its identity.
Correct Answer
B. False
Explanation
During a chemical change, the form of a substance is indeed altered, but its identity is also changed. Chemical reactions involve the rearrangement of atoms and the formation of new substances with different properties. Therefore, the statement that the identity of a substance remains the same during a chemical change is incorrect.
3.
A(n)____ is a group of atoms that are joined together by chemical bonds.
Correct Answer
Molecule
Explanation
A molecule is a group of atoms that are joined together by chemical bonds. Chemical bonds are formed when atoms share or transfer electrons, creating a stable arrangement. Molecules can be composed of atoms of the same element or different elements. They can exist as individual units or combine to form larger structures. Molecules are the fundamental building blocks of matter and play a crucial role in determining the properties and behavior of substances.
4.
Which of the following is NOT a charactereistic of a compound?
Correct Answer
C. Different samples have different properties.
Explanation
A compound is a pure substance made of two or more elements that are chemically combined. It has different properties from the elements that formed it, and it can be represented by a chemical formula. However, different samples of a compound will have the same properties, as the composition and arrangement of atoms in the compound are consistent. Therefore, the statement "Different samples have different properties" is not a characteristic of a compound.
5.
A change in matter in which energy is taken in is an endothermic change.
Correct Answer
A. True
Explanation
An endothermic change is a type of change in matter where energy is absorbed or taken in. This means that the system gains energy from its surroundings. In the context of this question, if a change in matter requires energy to be taken in, it is considered an endothermic change. Therefore, the correct answer is true.
6.
A measure of the average energy of random motion of particles of matter is______________
Correct Answer
Temperature
Explanation
Temperature is a measure of the average energy of random motion of particles of matter. It indicates the degree of hotness or coldness of a substance. The higher the temperature, the greater the average energy of the particles, resulting in increased random motion. Conversely, lower temperatures indicate lower average energy and reduced random motion. Temperature is an important concept in physics and plays a crucial role in various scientific and everyday applications.
7.
Anything that has mass and takes up space is an example of
Correct Answer
C. Matter
Explanation
Matter refers to anything that has mass and takes up space. It includes both solid, liquid, and gas forms. Energy, on the other hand, is the ability to do work or cause a change. Chemical change is a process that results in the formation of new substances. Temperature is a measure of the average kinetic energy of particles in a substance. Therefore, out of the given options, matter is the correct answer as it encompasses all physical substances that exist.
8.
Every chemical or physical change in matter includes a change in...
Correct Answer
D. Mass
Explanation
Every chemical or physical change in matter involves a rearrangement of atoms or molecules, but the total number of atoms or molecules remains constant. This means that the mass of the matter before and after the change is the same. Therefore, a change in mass is always included in any chemical or physical change in matter.
9.
A(n) _____ of a pure substance can be observed without changing the substance.
Correct Answer
D. Physical property
Explanation
A physical property of a pure substance refers to a characteristic or behavior that can be observed or measured without altering the substance's chemical composition. This means that physical properties such as color, density, melting point, boiling point, and solubility can be determined without causing any chemical changes to the substance. In contrast, chemical properties describe how a substance interacts or reacts with other substances, resulting in a change in its chemical composition. Therefore, a physical property can be observed or measured without changing the substance itself.
10.
Electrical energy is the energy of electrically charged particles moving from one place to another.
Correct Answer
A. True
Explanation
Electrical energy is the energy associated with the movement of electrically charged particles. When these charged particles, such as electrons, flow through a conductor from one place to another, they transfer energy in the form of electrical energy. This energy can be harnessed and used to power various devices and systems. Therefore, the statement that electrical energy is the energy of electrically charged particles moving from one place to another is true.
11.
A chemical bond is
Correct Answer
C. The force that holds two atoms together.
Explanation
A chemical bond refers to the force that holds two atoms together. It is the attraction between the positively charged nucleus of one atom and the negatively charged electrons of another atom. This force allows atoms to form molecules and compounds by sharing, donating, or receiving electrons. Chemical bonds play a crucial role in determining the properties and behavior of substances, as they determine how atoms are arranged and interact with each other.
12.
Which of the following is an example of a chemical change?
Correct Answer
D. Burning fuel
Explanation
Burning fuel is an example of a chemical change because it involves a reaction where the fuel combines with oxygen to produce new substances, such as carbon dioxide, water vapor, and heat. This reaction results in a change in the chemical composition of the fuel, indicating a chemical change.
13.
Breaking down water into the elements of hydrogen and oxygen is an example of a chemical change.
Correct Answer
A. True
Explanation
Breaking down water into the elements of hydrogen and oxygen involves a chemical reaction, where the bonds between the hydrogen and oxygen atoms are broken and new bonds are formed. This process requires energy and results in the formation of new substances with different properties than the original water molecule. Therefore, it is considered a chemical change.
14.
______ is the ability to do work or cause change.
Correct Answer
Energy
Explanation
Energy is the ability to do work or cause change. It is the capacity of a system to perform tasks or exert force on another object. Energy can exist in various forms such as kinetic, potential, thermal, electrical, and chemical. It is a fundamental concept in physics and is essential for all processes and activities in the universe. Energy can be converted from one form to another, but it cannot be created or destroyed, according to the law of conservation of energy.
15.
Which of the following is NOT true of atoms?
Correct Answer
A. They are composed of molecules.
Explanation
Atoms are not composed of molecules. Atoms are the basic units of matter and are themselves made up of subatomic particles such as protons, neutrons, and electrons. Molecules, on the other hand, are formed when atoms combine together through chemical bonds.
16.
In science lab, this chemical, which is also a pure element, turned color when it reacted with some of the crime scene suspect chemicals.
Correct Answer
Iodine
Explanation
Iodine is a chemical element that can turn color when it reacts with certain substances. In a science lab, it is possible that iodine was used to test for the presence of specific chemicals at a crime scene. When iodine reacts with these suspect chemicals, it undergoes a color change, indicating their presence. Therefore, iodine is a correct answer for this question.
17.
Ice is an example of the liquid state of matter.
Correct Answer
B. False
Explanation
Ice is actually an example of the solid state of matter, not the liquid state. When water freezes, it undergoes a phase change and becomes a solid, which is ice. Therefore, the correct answer is False.
18.
In the CSICT crime scene lab, this liquid acid was an example of a chemical change by producing bubbles when it reacted with some of the powder from the suspects.
Correct Answer
Acetic
Explanation
The given answer "Acetic" is the correct answer because acetic acid is known to react with certain powders to produce bubbles, indicating a chemical change. This suggests that the liquid acid in the CSICT crime scene lab is acetic acid.
19.
In the diagram below, "A" represents a pure substance or a mixture?
Correct Answer
Pure substance
Explanation
The diagram does not provide any information or context to determine whether "A" represents a pure substance or a mixture. Therefore, it is not possible to provide an explanation for the given correct answer.
20.
In the diagram below does "B" represents a pure substance or a mixture?
Correct Answer
Mixture
Explanation
The diagram is not provided, so it is difficult to determine the exact reason why "B" represents a mixture. However, in general, a mixture is a combination of two or more substances that are physically combined and can be separated by physical means. This could include mixtures of different elements, compounds, or both. Without further information, it can be assumed that "B" in the diagram represents a combination of different substances, hence making it a mixture.
21.
In the diagram below, does "C" represent a pure substance or a mixture?
Correct Answer
Mixture
22.
In the diagram below, does "D" represent a pure substance or a mixture?
Correct Answer
Pure substance
Explanation
In the given diagram, "D" represents a pure substance. A pure substance is a substance that is made up of only one type of particle, either atoms or molecules. It does not contain any other substances mixed in it. Therefore, "D" in the diagram is a pure substance.
23.
IS AN ELEMENT OR COMPOUND REPRESENTED IN FIGURE "D" beIow?
Correct Answer
Compound
Explanation
The given answer is "Compound" because a compound is a substance made up of two or more different elements chemically bonded together. Without any additional information or context, it is not possible to determine the specific compound represented in the figure "D" below.