Classification Of Matter 4

Mercury is an element because it is a pure substance that cannot be broken down into simpler substances by chemical means. It is represented by the symbol Hg on the periodic table and is a heavy, silver-colored metal that is liquid at room temperature. Mercury is unique in that it is the only metal that exists in liquid form under normal conditions. It has a variety of industrial and scientific uses, including in thermometers, barometers, and electrical switches.

When vinegar and baking soda react, they undergo a chemical reaction that produces a new substance, carbon dioxide gas. This indicates that a chemical change has occurred. In a chemical change, the original substances are transformed into different substances with new properties. In this case, the vinegar and baking soda combine to form carbon dioxide, which is a gas. Therefore, the given statement is correct in stating that the reaction between vinegar and baking soda is a chemical change.

When iron rusts, it undergoes a chemical reaction with oxygen in the presence of moisture, forming iron oxide. This process is known as oxidation. The formation of iron oxide is a chemical change because the composition and properties of the iron are altered. The rust that forms on the outside of the metal is a different substance with different properties than the original iron. Therefore, the given statement is correct in categorizing the rusting of iron as a chemical change.

Gold is a chemical element with the symbol Au and atomic number 79. It is a dense, soft, malleable, and ductile metal. Gold is a pure substance and cannot be broken down into simpler substances by chemical means. Therefore, it is classified as an element.

Iron is a chemical element with the symbol Fe and atomic number 26. It is a lustrous, silvery-gray metal that is found in abundance on Earth. As an element, iron cannot be broken down into simpler substances by chemical reactions. It is a pure substance made up of only one type of atom. Therefore, the correct answer is element.

Boiling water at 100 degrees Celsius is a physical change because it involves a change in the state of water from a liquid to a gas, without any alteration in its chemical composition. The molecules in water gain enough energy to overcome the intermolecular forces holding them together, resulting in the formation of water vapor. This change can be reversed by cooling the vapor, causing it to condense back into liquid water.

When sugar dissolves into water, it undergoes a physical change. This is because the sugar molecules are dispersed throughout the water, forming a homogeneous mixture. No new substances are formed, and the chemical composition of both sugar and water remains unchanged. The process of dissolving is a physical process where the sugar particles are broken down and separated by the water molecules, but the individual sugar molecules themselves remain the same.

This is a chemical change because electrolysis involves the breaking down of water molecules into hydrogen and oxygen atoms through the application of an electric current. This process results in the formation of new substances with different chemical properties from the original water molecules.

Nitrogen is an example of an element because it is a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom, which is nitrogen itself. Elements are the building blocks of matter and are represented by symbols on the periodic table.

Gasoline burning in the presence of oxygen is a chemical change because it involves a chemical reaction. During combustion, the molecules of gasoline break apart and rearrange their atoms to form new substances, such as carbon dioxide and water vapor. This process releases energy in the form of heat and light. Therefore, the transformation of gasoline into different compounds through the combustion process is a chemical change.

Coffee is considered a homogeneous mixture because it is composed of multiple substances that are uniformly distributed throughout. When coffee is brewed, the water, coffee grounds, and any added ingredients (such as sugar or milk) all mix together to create a uniform solution. This means that no matter where you sample from the mixture, the composition will be the same. There are no visible differences or separations between the components, making it a homogeneous mixture.

Pure water is a compound. A compound is a substance composed of two or more elements that are chemically combined in a fixed ratio. Water is composed of two elements, hydrogen and oxygen, which are chemically bonded together in a fixed ratio of 2:1. Therefore, pure water meets the criteria of being a compound.

Table salt, sodium chloride, is a compound. A compound is a substance composed of two or more elements chemically bonded together in a fixed ratio. Sodium chloride is formed by the chemical bonding of sodium (Na) and chlorine (Cl) atoms in a 1:1 ratio. It has a distinct chemical formula (NaCl) and unique properties different from its constituent elements. Therefore, table salt is classified as a compound.

Carbon dioxide is a compound because it is made up of two different elements, carbon and oxygen. In a compound, the elements are chemically bonded together in a fixed ratio. In the case of carbon dioxide, one carbon atom is bonded to two oxygen atoms. This chemical bonding creates a new substance with different properties than the individual elements.

A heterogeneous mixture is a combination of different substances that are not evenly distributed throughout the mixture. In the case of vegetable soup, it is made up of various vegetables, spices, and possibly other ingredients like meat or broth. These components are not uniformly distributed, and the soup may have different textures, colors, and flavors in different parts. Therefore, vegetable soup can be classified as a heterogeneous mixture.

The ocean is a heterogeneous mixture because it is composed of various substances that are not evenly distributed throughout. It contains a combination of different elements, compounds, and particles such as salt, minerals, gases, and organic matter. These components are not uniformly mixed, and their concentrations can vary from one region to another. Additionally, the ocean exhibits distinct layers and zones with different physical and chemical properties, further indicating its heterogeneous nature.

Burning wood is an example of a chemical change because it involves a chemical reaction. When wood burns, it undergoes a combustion reaction, combining with oxygen in the air to produce carbon dioxide, water vapor, and heat. This process results in a change in the chemical composition of the wood, transforming it into different substances. Physical changes, on the other hand, do not involve a change in the chemical composition of a substance. Magical change is not a scientifically recognized concept, making it an invalid option.

Raisin oatmeal is considered a heterogeneous mixture because it is composed of different components that can be easily distinguished. In this case, the raisins and oats are mixed together, but they retain their individual characteristics and can be visually identified. A homogeneous mixture, on the other hand, would have a uniform composition throughout, with no visible differences between its components. A compound, on the other hand, is a substance formed by the chemical combination of two or more elements, which is not the case with raisin oatmeal. Therefore, the correct answer is a heterogeneous mixture.

Calcium chloride is a compound because it is formed by the chemical combination of calcium and chlorine. A compound is a substance composed of two or more elements that are chemically bonded together. In the case of calcium chloride, calcium and chlorine atoms are bonded together to form the compound.

Tap water is a mixture because it is composed of various substances such as minerals, chemicals, and impurities dissolved in water. These components can be separated by physical means, such as filtration or distillation. Additionally, tap water can vary in composition depending on the source and treatment process, further supporting the idea that it is a mixture rather than a compound or element.