Matter And Energy Unit Test 777 (English)

Atoms are the correct answer because they are the smallest particles that make up all matter. Genes are segments of DNA that contain instructions for building proteins, not particles of matter. Minerals are inorganic substances found in the earth, not particles of matter. Cells are the basic structural and functional units of living organisms, not particles of matter. Therefore, atoms best fit the description of the tiny particles that make up all matter.

Diagram 2 represents molecules of matter in the solid phase because the molecules are tightly packed together in a regular pattern. This is characteristic of solids, where the particles are held closely together by strong intermolecular forces. Diagram 1 shows particles that are not tightly packed and are more spread out, which is not characteristic of solids. Diagrams 3 and 4 show particles that are not held together in a regular pattern, which is also not characteristic of solids. Therefore, diagram 2 is the best representation of molecules of matter in the solid phase.

The diagram shows a light wave passing through a material and changing direction. This phenomenon is known as refraction, which occurs when light waves travel from one medium to another with a different refractive index. Therefore, the statement "Light waves are refracted by some materials" best describes the property of light waves illustrated in the diagram.

The correct answer is the Periodic Table. Scientists use the Periodic Table to determine the properties of elements. It organizes all known elements based on their atomic number, electron configuration, and recurring chemical properties. This allows scientists to understand and predict the behavior and characteristics of different elements, such as their atomic mass, atomic radius, electronegativity, and more. The Periodic Table is an essential tool in chemistry and helps scientists study and analyze the properties of elements.

In diagram 2, the two different symbols representing atoms are combined and rearranged to form a completely new and different symbol. This indicates a chemical change, as the atoms have undergone a chemical reaction and formed a new substance. In the other diagrams, the symbols representing atoms are simply mixed together without any rearrangement or formation of new substances, which indicates a physical change rather than a chemical change.

When hydrochloric acid is added to a piece of zinc, a chemical reaction occurs. This is evident from the formation of zinc chloride and the release of hydrogen gas. In a chemical reaction, new substances are formed with different properties from the original substances. In this case, the zinc and hydrochloric acid react to form zinc chloride, which is a completely different compound. Additionally, the release of hydrogen gas indicates that a chemical change has taken place. Therefore, the correct answer is that this is an example of a chemical reaction.

When a person speaks into a telephone, the sound energy produced by their voice is converted mostly into electrical energy. This is because the sound waves created by the person's voice cause the microphone in the telephone to vibrate. These vibrations are then converted into electrical signals, which are transmitted through the telephone wires to the receiver. The electrical signals are then converted back into sound waves, allowing the person on the other end of the line to hear the speaker's voice.

On a sunny day, the shirt dries because the water molecules in the fabric gain heat energy from the sun. This increased heat energy causes the water molecules to gain enough kinetic energy to overcome the forces of attraction between them, leading to the process of evaporation. As a result, the water molecules transition from a liquid state to a gaseous state, allowing the shirt to dry.

Heat energy is transferred within the liquid water in a pond through convection currents. Convection is the process by which heat is transferred through the movement of a fluid, in this case, the water. As the water near the bottom of the pond is heated by the sun or other heat sources, it becomes less dense and rises to the surface. This movement creates a current, carrying the heat energy with it. At the surface, the water cools down and becomes denser, then sinks back down to be heated again. This continuous cycle of rising and sinking creates convection currents, allowing heat energy to be distributed throughout the water in the pond.

The chemical symbol CO represents carbon monoxide, which is a compound composed of carbon and oxygen atoms. Therefore, CO is the only substance listed that is a compound. Si, Fe, and He are all chemical symbols for elements (silicon, iron, and helium) and not compounds.

Heat energy is needed to change water from a liquid to a gas. When heat is applied to water, the molecules gain energy and move faster, causing the water to evaporate and change into a gaseous state. This process is known as evaporation, and it requires the input of heat energy.

The correct answer is helium and oxygen. Helium (He) and oxygen (O) are both elements, meaning they cannot be broken down into simpler substances. Hydrochloric acid (HCl) and carbonic acid (H2CO3) are compounds made up of multiple elements, while carbon dioxide (CO2) and water (H2O) are also compounds.

An electron is negatively charged because it has a surplus of electrons compared to its protons. A proton, on the other hand, is positively charged because it has a surplus of protons compared to its electrons. This charge difference between electrons and protons is what allows for the attraction and formation of stable atoms.

When the student crumples up the sheet of paper, the property that changes is the shape of the paper. The paper goes from being flat to being crumpled, which alters its shape.

Diagram B represents electromagnetic energy with the shortest wavelength. This can be determined by comparing the wavelengths of the waves in each diagram. In Diagram B, the distance between the peaks of the waves is the shortest, indicating a shorter wavelength.

The elements on the Periodic Table are arranged in order of increasing atomic number. This is because the atomic number represents the number of protons in the nucleus of an atom, which determines the element's identity. As you move across the Periodic Table from left to right, the atomic number increases by one, indicating the addition of one proton. This arrangement allows for a systematic organization of elements based on their atomic properties and provides valuable information about their chemical behavior and relationships.

Water is usually found in nature as a liquid, solid, and gas. This is because water can exist in three different states of matter depending on the temperature and pressure. At normal room temperature and pressure, water exists as a liquid. At lower temperatures, it can freeze and become a solid (ice), while at higher temperatures, it can evaporate and become a gas (water vapor). Therefore, water is the substance that can exist in all three states naturally.

The symbols in the model represent atoms. In the diagram, the symbols "H" and "O" represent the atoms of hydrogen and oxygen, respectively. Atoms are the basic building blocks of matter and they combine to form molecules. In the case of water, two hydrogen atoms bond with one oxygen atom to form a water molecule (H2O). Therefore, the symbols in the model represent the atoms present in the molecule of water.

Graph 3 correctly shows the effect of heat energy on the motion of molecules of matter. As the heat energy increases, the motion of molecules also increases. This is represented by the increase in the amplitude of the graph. The graph shows a positive correlation between heat energy and molecular motion, indicating that as one increases, the other also increases.

Sound requires a medium to travel through, such as a solid, liquid, or gas, because it relies on the vibration of particles in the medium to transmit energy. In a vacuum, there is no medium for sound waves to propagate, so sound cannot travel. This is because a vacuum is devoid of particles, making it impossible for them to vibrate and transmit sound waves.

The water level in the glass of water decreases can be evidence that the water is undergoing a phase change because when water evaporates, it changes from a liquid phase to a gas phase. As the water molecules gain energy, they become more energetic and move faster, eventually escaping the liquid surface and entering the air as water vapor. This process leads to a decrease in the water level in the glass.

When light passes from one medium to another, such as from air to water, it changes speed and direction. This phenomenon is known as refraction. In this scenario, when light from the fish travels from the water to the air, it bends or changes direction at the water-air interface. As a result, the fish appears to be at a different position (A) than its actual position (B) below the surface of the water. Therefore, refraction is responsible for the apparent position of the fish being different from its actual position.

When air is pumped out of the vacuum jar, the sound level of the ringing bell will decrease and eventually become inaudible. This is because sound requires a medium, such as air, to travel through. In the absence of air in the jar, there is no medium for the sound waves to propagate, resulting in the decrease and eventual disappearance of the sound.

Sound waves are created by vibrations because sound is a mechanical wave that requires a medium, such as air, water, or solids, to propagate. When an object vibrates, it causes the surrounding particles of the medium to vibrate, creating a disturbance that travels as a sound wave. This vibration of particles is what allows sound waves to be produced and transmitted from a source to a receiver.