Classify each of the following as a pure substance, a solution, or a heterogeneous mixture: c. a wood plank

Verified step by step guidance

1. Understand the definitions: A pure substance has a uniform and definite composition, a solution is a homogeneous mixture with uniform composition throughout, and a heterogeneous mixture has a non-uniform composition.
2. Consider the composition of a wood plank: Wood is composed of various components such as cellulose, lignin, water, and other organic compounds.
3. Evaluate the uniformity: In a wood plank, these components are not uniformly distributed throughout the material.
4. Determine the classification: Since the components of a wood plank are not uniformly distributed, it does not fit the definition of a pure substance or a solution.
5. Conclude that a wood plank is a heterogeneous mixture because it has a non-uniform composition with distinct regions of different materials.

Key Concepts

Pure Substance

A pure substance consists of a single type of particle and has a uniform and definite composition. It can be an element, like oxygen, or a compound, like water. Pure substances have consistent properties throughout, such as boiling and melting points, which distinguish them from mixtures.

Solution

A solution is a homogeneous mixture where one substance (the solute) is dissolved in another (the solvent). Solutions have a uniform composition and properties throughout, meaning that any sample taken from the solution will have the same ratio of solute to solvent. Common examples include saltwater and sugar dissolved in tea.

Heterogeneous Mixture

A heterogeneous mixture consists of two or more substances that remain physically separate and can be distinguished from one another. The components can vary in composition and properties throughout the mixture, such as in a salad or a wood plank, where different materials can be identified and separated.