1.
One example of a physical change is
Correct Answer
D. dissolving salt in water.
Explanation
Dissolving salt in water is an example of a physical change because it does not alter the chemical composition of the substances involved. When salt is dissolved in water, it breaks down into individual ions, which become dispersed throughout the water. This process can be reversed by evaporating the water, leaving behind the original salt crystals. Therefore, the physical properties of the salt and water are changed, but the substances themselves remain the same.
2.
One example of a chemical change is
Correct Answer
B. burning wood.
Explanation
Burning wood is an example of a chemical change because it involves a chemical reaction. When wood is burned, it undergoes a combustion reaction where it reacts with oxygen in the air to produce heat, light, carbon dioxide, and water vapor. This chemical reaction results in the formation of new substances with different properties than the original wood, making it a clear example of a chemical change.
3.
The energy of matter in motion is called
Correct Answer
A. kinetic energy.
Explanation
Kinetic energy refers to the energy possessed by an object due to its motion. This energy is dependent on the mass and velocity of the object. Potential energy, on the other hand, refers to the energy stored by an object based on its position or state. Chemical energy is the energy stored in the bonds of chemical compounds. Electromagnetic energy refers to the energy carried by electromagnetic waves, such as light or radio waves. Out of these options, kinetic energy is the most appropriate term to describe the energy of matter in motion.
4.
Table sugar and table salt are examples of
Correct Answer
D. pure substances.
Explanation
Table sugar and table salt are both pure substances because they are composed of only one type of molecule. Table sugar is made up of sucrose molecules, while table salt is made up of sodium chloride molecules. In contrast, mixtures are composed of two or more different substances that are physically combined, and elements are pure substances that cannot be broken down into simpler substances. Therefore, the correct answer is pure substances.
5.
Substances that CANNOT be broken down chemically into other substances are
Correct Answer
A. elements.
Explanation
Elements are substances that cannot be broken down chemically into other substances. They are composed of only one type of atom and cannot be further simplified or decomposed. In contrast, compounds are made up of two or more different elements chemically bonded together, mixtures are combinations of different substances that can be physically separated, and solutions are homogeneous mixtures where one substance is dissolved in another. Therefore, the correct answer is elements.
6.
The measurement of the force of gravity on an object is the object’s
Correct Answer
C. weight.
Explanation
The measurement of the force of gravity on an object is its weight. Weight is the force exerted on an object due to gravity, and it is directly proportional to the mass of the object. The greater the mass, the greater the force of gravity and therefore the greater the weight.
7.
The measurement of how much matter an object contains is its
Correct Answer
C. mass.
Explanation
Mass is the measurement of how much matter an object contains. It is a fundamental property of matter and is independent of the object's location. Volume, on the other hand, is the amount of space occupied by an object. Weight is the force exerted on an object due to gravity, which can vary depending on the object's location. Melting point is the temperature at which a substance changes from a solid to a liquid state.
8.
The measurement of how much mass is contained in a given volume is called
Correct Answer
D. density.
Explanation
Density is the measurement of how much mass is contained in a given volume. It is a characteristic property of a substance and is calculated by dividing the mass of the substance by its volume. Weight, melting point, and boiling point are not measurements of mass in a given volume, making density the correct answer.
9.
The density of a block of wood with a volume of 50 cubic centimeters and a mass of 100 grams is
Correct Answer
A. 2 g/cm3
Explanation
The density of a substance is calculated by dividing its mass by its volume. In this case, the mass of the block of wood is given as 100 grams and the volume is given as 50 cubic centimeters. By dividing the mass (100 grams) by the volume (50 cubic centimeters), we get a density of 2 grams per cubic centimeter (g/cm3).
10.
All elements are composed of extremely small particles called
Correct Answer
C. atoms.
Explanation
All elements are composed of extremely small particles called atoms. Atoms are the basic building blocks of matter and cannot be further divided into simpler substances. Compounds are formed by the combination of different atoms, while mixtures are made up of two or more substances that are physically combined but not chemically bonded. Molecules, on the other hand, are formed when two or more atoms are chemically bonded together. Therefore, the correct answer is atoms.
11.
Which of the following is NOT an example of a chemical change?
Correct Answer
C. salt dissolving in a glass of water
Explanation
Salt dissolving in a glass of water is not an example of a chemical change because it is a physical change. In this process, the salt molecules are simply separating and dispersing throughout the water, but no new substances are being formed. The chemical composition of both the salt and the water remains the same.
12.
The ability to do work or cause change describes
Correct Answer
D. energy.
Explanation
The ability to do work or cause change is a fundamental characteristic of energy. Energy can exist in various forms such as kinetic energy, potential energy, thermal energy, and electromagnetic energy. It is the capacity of a system to perform work or transfer heat. Temperature, density, and matter are not directly related to the ability to do work or cause change, making energy the correct answer.
13.
The change in which ice absorbs energy and melts is a(n)
Correct Answer
A. Endothermic change.
Explanation
When ice absorbs energy and melts, it is undergoing an endothermic change. Endothermic changes absorb heat from the surroundings, causing a decrease in temperature. In this case, the ice absorbs energy from its surroundings, causing it to melt and transition from a solid to a liquid state.
14.
What holds atoms together in a molecule?
Correct Answer
D. chemical bonds
Explanation
Chemical bonds hold atoms together in a molecule. Chemical bonds are formed when atoms share or transfer electrons, resulting in the formation of stable molecules. These bonds can be covalent, where electrons are shared between atoms, or ionic, where electrons are transferred from one atom to another. Chemical bonds play a crucial role in determining the properties and behavior of molecules, as they determine the arrangement and connectivity of atoms within a molecule.
15.
Fireworks exploding in the sky and giving off light are an example of a(n)
Correct Answer
B. exothermic change.
Explanation
Fireworks exploding and giving off light is an example of an exothermic change because it releases energy in the form of light and heat. In an exothermic reaction, energy is released from the system into the surroundings, resulting in a temperature increase. The combustion of the fireworks produces a rapid release of energy in the form of heat and light, causing the explosion and the display of colors in the sky.
16.
The volume of an irregular object can be measured by
Correct Answer
A. multiplying the object’s length, width, and height.
Explanation
The correct answer is multiplying the object's length, width, and height. This is because the volume of an irregular object can be calculated by measuring its dimensions and multiplying them together. By multiplying the length, width, and height, we can determine the amount of space the object occupies. This method is commonly used for objects that do not have a regular shape, such as rocks or pieces of wood.
17.
In the laboratory, volumes of liquid are usually measured with a(n)
Correct Answer
D. Graduated cylinder.
Explanation
A graduated cylinder is commonly used in laboratories to measure the volume of liquids. It is a cylindrical container with markings on the side, allowing for precise measurement of liquid volume. Electrodes are typically used for measuring electrical properties, not volumes of liquid. Scales are used for measuring weight, not volume. Triple-beam balances are used for measuring mass, not volume. Therefore, the most appropriate instrument for measuring liquid volumes in a laboratory setting is a graduated cylinder.
18.
Anything that has mass and takes up space is called
Correct Answer
A. matter.
Explanation
The correct answer is matter. Matter refers to anything that has mass and occupies space. This includes both tangible objects and substances, such as solids, liquids, and gases. Energy, on the other hand, is the ability to do work or cause change, and is not considered to have mass or occupy space. Heterogeneous and homogeneous refer to the composition or uniformity of a substance or mixture, and are not the correct terms to describe anything that has mass and takes up space.
19.
How would you calculate the density of an object?
Correct Answer
B. Divide its mass by its volume.
Explanation
To calculate the density of an object, you need to divide its mass by its volume. Density is defined as the amount of mass per unit volume, so dividing the mass by the volume gives you the density value. This calculation allows you to determine how much mass is present in a given volume of the object, providing a measure of how tightly packed the particles are within the object.
20.
What characteristics listed below do photosynthesis and combustion NOT share?
Correct Answer
B. Both are endothermic.
Explanation
Photosynthesis and combustion do not share the characteristic of being endothermic. Combustion is an exothermic process, meaning it releases energy in the form of heat and light. On the other hand, photosynthesis is an endothermic process, as it requires energy from sunlight to convert carbon dioxide and water into glucose and oxygen.
21.
Lemonade consists of several substances that are NOT chemically combined, so lemonade is classified as a(n)
Correct Answer
C. mixture.
Explanation
Lemonade is classified as a mixture because it consists of several substances that are not chemically combined. In a mixture, the substances retain their individual properties and can be physically separated. In the case of lemonade, it is made by mixing lemon juice, water, sugar, and other ingredients together, but they do not chemically react to form a new substance.
22.
How do liquid water, ice, and water vapor differ from each other?
Correct Answer
A. They are different states of matter.
Explanation
Liquid water, ice, and water vapor differ from each other because they exist in different states of matter. Liquid water is the state in which water is commonly found at room temperature, ice is the solid state of water that forms at lower temperatures, and water vapor is the gaseous state of water that occurs when water is heated. Each state has different properties and behaviors, such as density, shape, and ability to flow. The fact that they are different states of matter explains the differences between them.
23.
If you heat a liquid and measure the temperature at which it boils, you are measuring a(n)
Correct Answer
B. pHysical property.
Explanation
When you heat a liquid and measure the temperature at which it boils, you are measuring a physical property. This is because boiling point is a characteristic property of a substance that can be observed without changing its chemical composition. It is a measure of the temperature at which the vapor pressure of the liquid equals the atmospheric pressure, causing the liquid to change into a gas.
24.
If you describe methane as a gas that easily catches fire, you are describing a
Correct Answer
C. Chemical property.
Explanation
Describing methane as a gas that easily catches fire indicates its behavior and reactivity, which is a characteristic of its chemical composition. This information pertains to the chemical property of methane rather than its physical state or formula.
25.
During photosynthesis, plants transform electromagnetic energy from the sun into
Correct Answer
C. chemical energy.
Explanation
During photosynthesis, plants use the energy from sunlight to convert carbon dioxide and water into glucose and oxygen. This process occurs in the chloroplasts of plant cells, specifically in the thylakoid membrane. The sunlight is absorbed by the chlorophyll pigment, which then transfers the energy to molecules that are involved in the synthesis of glucose. This glucose is stored as chemical energy in the plant, which can be later used for various metabolic processes such as growth, reproduction, and cellular respiration. Therefore, the correct answer is chemical energy.