Question

Define physical property and chemical property. Identify each type of property in the following statements: (a) Yellow-green chlorine gas attacks silvery sodium metal to form white crystals of sodium chloride (table salt). (b) A magnet separates a mixture of black iron shavings and white sand.

Short answer

(a) Chemical property (b) Physical property

Step-by-step solution

Define Physical Property

A physical property is a characteristic of a substance that can be observed or measured without changing the substance's chemical identity. Examples include color, density, mass, volume, and state of matter (solid, liquid, gas).

Define Chemical Property

A chemical property is a characteristic of a substance that becomes evident during a chemical reaction; it describes the substance's ability to undergo changes that transform it into different substances. Examples include flammability, reactivity with other chemicals, and acidity.

Identify Type of Property in Statement (a)

Statement (a) describes yellow-green chlorine gas reacting with silvery sodium metal to form white crystals of sodium chloride (table salt). This is a chemical property because it involves a chemical reaction that changes the substances' chemical identities.

Identify Type of Property in Statement (b)

Statement (b) describes a magnet separating a mixture of black iron shavings and white sand. This is a physical property because the substances are separated without changing their chemical identities. The process relies on the physical characteristic of magnetism.

Key concepts

physical property

A physical property is a characteristic of a substance that you can observe or measure without changing the substance itself. For example, if you look at water, you can see that it's colorless and flows easily. These are physical properties because they don't change the chemical makeup of the water. Other examples of physical properties include:

• Mass
• Volume
• Density
• Color
• State of matter (solid, liquid, gas)

Physical properties are useful because they help us identify and classify substances without altering their chemical structure.

chemical property

A chemical property describes a substance’s potential to undergo a specific chemical change. For example, the flammability of wood is a chemical property because it describes the wood’s ability to burn and turn into ash. Unlike physical properties, chemical properties can only be observed during a chemical reaction. Other examples include:

• Reactivity with other chemicals
• Acidity or basicity (pH)
• Oxidation states
• Heat of combustion

Identifying chemical properties is crucial for understanding how substances interact and transform during chemical reactions.

chemical reaction

A chemical reaction occurs when substances undergo a molecular change to form new substances. For example, when yellow-green chlorine gas reacts with silvery sodium metal, they form white crystals of sodium chloride (table salt). This reaction changes the chemical identities of the reactants (chlorine and sodium) into a new product (sodium chloride). Indicators of a chemical reaction include:

• Formation of a new substance
• Color change
• Release or absorption of energy (heat, light)
• Formation of gas or precipitate

Chemical reactions are fundamental to chemistry and help explain how different materials and substances interact in the natural world.

magnetism

Magnetism is a physical property that allows certain materials to attract or repel each other. For example, a magnet can separate a mixture of black iron shavings from white sand because iron is magnetic and sand is not. This separation does not change the chemical identities of either substance, as it solely relies on the physical characteristic of magnetism. Key points about magnetism:

• It's a force that can attract (pull closer) or repel (push away) materials.
• Common magnetic materials include iron, nickel, and cobalt.
• Magnetism is used in various applications, from separating mixtures to generating electricity in power plants.

Understanding magnetism is essential for exploring physical processes and developing technology.