Holt Science Spectrum - Physical Science

Solids, gases, and liquids are indeed the three states of matter. Solids have a definite shape and volume, with particles tightly packed together. Gases have no definite shape or volume, with particles spread far apart. Liquids have a definite volume but no definite shape, with particles that are close together but can still move around. Therefore, the statement is true.

Atoms are the fundamental building blocks of matter and are responsible for making up elements. They are the smallest units of an element that retain the chemical properties of that element. Atoms consist of a nucleus, which contains protons and neutrons, and electrons that orbit around the nucleus. Different combinations of atoms form different elements, and elements combine to form compounds. Therefore, atoms are essential in the composition of matter and the existence of elements.

This statement is false because atoms are the basic building blocks of elements. Elements are composed of atoms, which are the smallest unit of matter that retains the properties of an element. Therefore, atoms do make up elements.

A chemical change refers to a transformation that takes place when a substance undergoes a change in its composition, resulting in the formation of one or more new substances. This change involves the breaking and forming of chemical bonds, leading to a rearrangement of atoms and a change in the chemical properties of the substance. Unlike a physical change, which only alters the physical state or appearance of a substance, a chemical change involves a fundamental alteration in the chemical nature of the substance.

Burning is a chemical property because it involves a chemical reaction. When a substance undergoes burning, it combines with oxygen to produce heat, light, and often a change in its chemical composition. This chemical reaction is characteristic of the substance and cannot be easily reversed. Therefore, burning can be classified as a chemical property.

Evaporation is the process by which a substance changes from a liquid state to a gaseous state. It occurs when the molecules of a liquid gain enough energy to overcome the forces of attraction between them and escape into the surrounding environment as vapor. This process does not involve any change in the substance's state from gas back to liquid or solid. Therefore, the correct answer is "the change of a substance from a liquid to a gas."

Elements are represented with a one or two letter symbol. Each element on the periodic table is assigned a unique symbol, usually consisting of one or two letters. These symbols are used to represent elements in chemical equations, formulas, and scientific notations. For example, the symbol "H" represents hydrogen, "O" represents oxygen, and "Na" represents sodium. These symbols allow scientists to easily identify and communicate about different elements.

Compounds are defined as a combination of two or more elements bonded together. This means that compounds are formed when different elements chemically react and combine to create a new substance with its own unique properties. The bonding between the elements is what holds the compound together and gives it its characteristic properties.

The Law of Conservation of Mass states that mass cannot be created or destroyed in a chemical reaction. This means that the total mass of the reactants in a chemical reaction must be equal to the total mass of the products. In other words, the mass of the substances involved in a chemical reaction remains constant before and after the reaction takes place. This law is a fundamental principle in chemistry and is based on the idea that atoms are neither created nor destroyed during a chemical reaction, but are rearranged to form new substances.

The Law of Conservation of Energy states that energy cannot be created or destroyed, but it can only be transferred or transformed from one form to another. This means that the total amount of energy in a closed system remains constant over time. This principle is a fundamental concept in physics and is supported by numerous experimental observations and mathematical equations. It has wide-ranging applications in various fields, including mechanics, thermodynamics, and electromagnetism.

The melting point is the temperature at which a solid substance changes its state and becomes a liquid. It is also known as the freezing point because it is the temperature at which a liquid substance changes its state and becomes a solid.

A physical change refers to a transformation in the physical state or characteristics of a substance, where no alteration in its composition occurs. This means that during a physical change, the substance may change its form, shape, size, or state (such as from solid to liquid or gas), but the fundamental chemical properties and composition remain unchanged. Examples of physical changes include melting, freezing, boiling, dissolving, or changes in texture or appearance.

Sublimation is the process in which a substance transitions directly from a solid to a gas state, bypassing the liquid state. This occurs when the substance is heated and the vapor pressure of the solid exceeds the atmospheric pressure. The molecules gain enough energy to break the intermolecular forces holding them in the solid state and escape into the gas phase. This process is commonly observed in substances like dry ice (solid carbon dioxide) and mothballs (solid naphthalene).

The correct answer is a) viscosity, b) condensation, c) evaporation, d) pressure, e) sublimation, f) energy, and g) pressure. Viscosity refers to the resistance of a fluid to flow, condensation is the change of a substance from a gas to a liquid, evaporation is the change of a substance from a liquid to a gas, pressure is the force exerted per unit area of a surface, sublimation is the change of a substance from a solid to a gas, and energy refers to the ability to change or move matter.

The answer is a) matter because it corresponds to the definition of "anything that has mass and occupies space." b)chemistry corresponds to the definition of "the study of matter and how it changes." c) molecule corresponds to the definition of "the smallest unit of a substance that exhibits all of the property characteristic of that substance." d) compound corresponds to the definition of "a substance made of atoms of more than one element bound together." e) element corresponds to the definition of "a substance that cannot be broken down into simpler substances." f) pure substance corresponds to the definition of "any matter that has a fixed composition and definite properties." g) mixture corresponds to the definition of "a combination of more than one pure substance." h) miscible corresponds to the definition of "describes 2 or more liquids that are able to dissolve into each other in various proportions." i) immiscible corresponds to the definition of "describes 2 or more liquids that do NOT mix into each other." j) chemical formula corresponds to the definition of "the chemical symbols and numbers indicating the atoms contained in the basic unit of a substance." k) atom corresponds to the definition of "the smallest particle that has the properties of an element."

Molecules are composed of atoms bonded together and are the smallest unit of a substance that retains all the chemical properties of that substance. In the case of water, a molecule of water consists of two hydrogen atoms bonded to one oxygen atom, and this arrangement gives water its unique properties such as being a liquid at room temperature, having a high boiling point, and exhibiting polarity. Therefore, molecules accurately describe the smallest unit of a substance that displays all its characteristic properties.

A physical property is a characteristic of a substance that can be observed or measured without changing the composition of the substance. This means that the substance remains the same even when its physical properties are observed or measured. Examples of physical properties include color, density, melting point, boiling point, and conductivity. These properties help identify and classify substances based on their observable characteristics, without altering their chemical makeup.

The given statement is true. Nitrogen is a major element in the human body, comprising about 3% of the total body weight. On the other hand, phosphorus is present in smaller amounts, accounting for about 1% of the body weight. Therefore, the proportion of nitrogen in the human body is indeed greater than the proportion of phosphorus.

Pure substances have fixed compositions and definite properties. Unlike mixtures, which can vary in composition, pure substances consist of only one type of atom or molecule. This means that pure substances have consistent properties and behave in predictable ways. Examples of pure substances include elements and compounds. Elements are made up of only one type of atom, while compounds are made up of two or more different types of atoms bonded together in fixed ratios. Overall, pure substances are characterized by their uniformity and consistent properties.

The boiling point is the temperature at which a liquid changes its phase from liquid to gas. It is the temperature at which the vapor pressure of the liquid equals the atmospheric pressure. At the boiling point, bubbles of vapor form within the liquid and rise to the surface, causing the liquid to boil. Therefore, the boiling point is the temperature at which a liquid becomes a gas below the surface.

The statement is true because the proportion of magnesium in the Earth's composition is less than the proportion of silicon. This means that silicon is more abundant in the Earth compared to magnesium.

The statement is false because the proportion of sulfur in the Earth is actually higher than the proportion of calcium. Sulfur is the tenth most abundant element in the Earth's crust, while calcium is the fifth most abundant. Therefore, the proportion of sulfur is greater than the proportion of calcium in the Earth.

The statement is true because the proportion of sodium in the human body is indeed less than the proportion of potassium. Sodium is an essential electrolyte that helps regulate fluid balance and nerve function, but it is found in smaller quantities compared to potassium. Potassium is also an essential electrolyte and plays a crucial role in maintaining heart health, muscle function, and nerve signaling. Therefore, the proportion of potassium in the human body is higher than that of sodium.

The statement is true because the proportion of iron in the earth is greater than the proportion of oxygen. Iron is one of the most abundant elements in the earth's crust, making up about 5% of it, while oxygen is the most abundant element, constituting about 46% of the earth's crust. Therefore, the proportion of iron is indeed greater than the proportion of oxygen in the earth.

Changing state does not change composition and mass. When a substance changes state, such as from a solid to a liquid or a gas, its composition remains the same. The molecules or atoms that make up the substance do not change. Additionally, the mass of the substance also remains constant during a change in state. This is because no particles are added or removed, only the arrangement and movement of the particles change.

The proportion of carbon in the human body is actually higher than the proportion of hydrogen. Carbon makes up about 18.5% of the body's mass, while hydrogen makes up about 9.5%. Therefore, the statement that the proportion of carbon is less than the proportion of hydrogen is false.

Condensation is the process in which a substance changes from a gas state to a liquid state. This occurs when the particles of the gas lose energy and come together to form liquid droplets. It is the opposite process of evaporation, where a substance changes from a liquid to a gas.

The correct answer includes the terms "homogeneous," "miscible," "heterogeneous," and "immiscible." Homogeneous mixtures are uniform throughout, with the components evenly distributed. Miscible substances can mix in all proportions to form a homogeneous mixture. Heterogeneous mixtures have visibly different components that are not evenly distributed. Immiscible substances cannot mix to form a homogeneous mixture and separate into distinct phases.

Buoyancy is the force with which a more dense fluid pushes a less dense substance. When an object is placed in a fluid, it displaces a certain amount of fluid. The fluid exerts an upward force on the object, which is called buoyancy. This force is equal to the weight of the fluid displaced by the object. If the object is less dense than the fluid, it will experience an upward buoyant force greater than its weight and will float. If the object is more dense than the fluid, the buoyant force will be less than its weight and it will sink.

Reactivity refers to the ability of a substance to chemically combine with another substance. It is a measure of how readily a substance undergoes a chemical reaction and forms new compounds. Reactivity can vary depending on the nature of the substances involved, their chemical properties, and the conditions under which the reaction takes place. Substances with high reactivity are more likely to react quickly and vigorously, while substances with low reactivity may require specific conditions or catalysts to initiate a reaction.

The density of a substance is calculated by dividing its mass by its volume. In this case, the mass of the metal is given as 75.7g and the volume is given as 6.7cm3. By dividing the mass by the volume, we get the density of the metal, which is 11.29 g/cm3.

The density of a substance is calculated by dividing its mass by its volume. In this case, the mass is given as 9.17 g and the volume is given as 10.0 cm3. By dividing the mass by the volume, we can calculate the density. Therefore, the density is calculated as 9.17 g / 10.0 cm3 = .917 g/cm3.

The equation D = m/v represents the relationship between density (D), mass (m), and volume (v). Density is defined as the mass of an object divided by its volume. This equation allows us to calculate the density of an object by dividing its mass by its volume.

A chemical property refers to the way a substance reacts with others to form new substances with different properties. It describes the behavior of a substance when it undergoes a chemical change or reaction. Unlike physical properties, which can be observed without changing the identity of the substance, chemical properties can only be observed when a substance interacts with another substance. These properties are important in understanding the reactivity and behavior of substances in various chemical processes and reactions.

The density of a material is defined as its mass divided by its volume. In this equation, the mass of the material is given as 83.75g and the volume is given as 125cm3. To find the density, we divide the mass by the volume: 83.75g / 125cm3 = 0.67 g/cm3. Therefore, the density of the material is 0.67 g/cm3.