Question

Which of the following statements is incorreet? (1) \Lambdall clements are homogencous (2) Compounds made up of a number of elements are hetcrogencous (3) \(\Lambda\) mixture is not always heterogencous (4) \Lambdair is an heterogencous mixture

Short answer

Statement (2) is incorrect.

Step-by-step solution

Understand the Definitions

Review the definitions of homogeneous, heterogeneous, elements, compounds, and mixtures. Homogeneous means having a uniform composition throughout, while heterogeneous means having a non-uniform composition.

Check Each Statement Against Definitions

Analyze statements based on definitions. Statement (1) says all elements are homogeneous. Statement (2) claims compounds made up of elements are heterogeneous. Statement (3) states a mixture is not always heterogeneous, implying it can be homogeneous. Statement (4) claims air is a heterogeneous mixture.

Identify Incorrect Statement

Determine which statement does not fit with your understanding of the definitions. Elements are homogeneous, so (1) is correct. A mixture can be homogeneous, making (3) correct. Air is a homogeneous mixture, making (4) incorrect. Compounds are homogeneous, not heterogeneous, making (2) incorrect.

Key concepts

definition of homogeneous

A homogeneous mixture is one that has the same composition throughout. This means that no matter where you sample the mixture, the composition and properties are the same. Examples of homogeneous mixtures include:

• Sugar dissolved in water
• Salt dissolved in water
• Air (when uniformly mixed)

Understanding homogeneous mixtures is crucial in recognizing that their uniformity applies throughout the entire mixture. This uniformity is key in distinguishing homogeneous mixtures from heterogeneous ones.

definition of heterogeneous

In contrast to homogeneous mixtures, heterogeneous mixtures have a non-uniform composition. This means that different samples from the mixture may have different compositions and properties. Examples of heterogeneous mixtures include:

• Salad
• Concrete
• Sand and water

The distinct and varying components in different parts of the mixture are what make it heterogeneous. Identifying these components visually or by texture is often possible in heterogeneous mixtures, unlike in homogeneous ones.

elements vs compounds

Understanding the difference between elements and compounds is crucial in chemistry. Elements are pure substances consisting of only one type of atom. They cannot be broken down into a simpler substance. Examples include:

• Hydrogen (H)
• Oxygen (O)
• Gold (Au)

On the other hand, compounds are substances formed by the chemical combination of two or more elements in fixed proportions. Examples of compounds include:

• Water (H₂O)
• Carbon dioxide (CO₂)
• Sodium chloride (NaCl)

Compounds can be broken down into their constituent elements through chemical reactions. The properties of compounds are often different from the properties of the elements that make them up. Recognizing and understanding these differences is foundational in studying chemistry.