Determine whether each molecular diagram represents a pure substance or a mixture. If it represents a pure substance, classify the substance as an element or a compound. If it represents a mixture, classify the mixture as homogeneous or heterogeneous.

Verified step by step guidance

1. Observe the molecular diagrams carefully to identify the types of particles present in each diagram.
2. For diagram (i), note that it contains only one type of particle, indicating a pure substance. Since all particles are identical and consist of single atoms, classify it as an element.
3. For diagram (ii), observe that it contains only one type of particle, but each particle is made up of different atoms bonded together, indicating a pure substance. Classify it as a compound.
4. For diagram (iii), note that it contains two distinct types of particles that are not uniformly mixed, indicating a mixture. Classify it as a heterogeneous mixture.
5. For diagram (iv), observe that it contains two distinct types of particles that are uniformly mixed, indicating a mixture. Classify it as a homogeneous mixture.

Key Concepts

Pure Substances vs. Mixtures

A pure substance consists of only one type of particle, which can be either an element or a compound. Elements are made of a single type of atom, while compounds consist of two or more different atoms chemically bonded together. In contrast, mixtures contain two or more different substances that are physically combined, which can be separated by physical means.

Homogeneous vs. Heterogeneous Mixtures

Homogeneous mixtures have a uniform composition throughout, meaning the different components are evenly distributed and not easily distinguishable. Examples include saltwater or air. Heterogeneous mixtures, on the other hand, have a non-uniform composition where the different components can be seen and separated, such as a salad or a mixture of sand and iron filings.

Molecular Representation

Molecular diagrams visually represent the arrangement of atoms in a substance. In these diagrams, similar colored spheres typically represent identical atoms, while different colors indicate different types of atoms. Analyzing these diagrams helps in identifying whether the substance is a pure substance or a mixture, and if it is a mixture, whether it is homogeneous or heterogeneous based on the arrangement and distribution of the spheres.