Classify each of the following as a pure substance or a mixture. If a mixture, indicate whether it is homogeneous or heterogeneous: (a) air (b) chocolate with almond

Verified step by step guidance

1. Understand the definitions: A pure substance has a uniform and definite composition, such as elements or compounds. A mixture consists of two or more substances physically combined, which can be homogeneous (uniform composition) or heterogeneous (non-uniform composition).
2. Examine air: Air is a mixture of gases, primarily nitrogen, oxygen, and small amounts of other gases. Since the composition is uniform throughout, air is classified as a homogeneous mixture.
3. Examine chocolate with almond: This consists of chocolate and almonds mixed together. The composition is not uniform throughout, as you can see and separate the almonds from the chocolate. Therefore, it is classified as a heterogeneous mixture.
4. Summarize the classification: (a) Air is a homogeneous mixture. (b) Chocolate with almond is a heterogeneous mixture.
5. Reflect on the characteristics: Homogeneous mixtures have the same composition throughout, while heterogeneous mixtures have visibly different parts or phases.

Key Concepts

Pure Substances

A pure substance consists of a single type of particle and has a uniform and definite composition. Examples include elements like oxygen and compounds like water. Pure substances have consistent properties throughout, such as boiling and melting points, which distinguish them from mixtures.

Mixtures

Mixtures are combinations of two or more substances that retain their individual properties. They can be classified as homogeneous, where the composition is uniform throughout (like saltwater), or heterogeneous, where the composition varies (like a salad). The components in a mixture can often be separated by physical means.

Homogeneous vs. Heterogeneous Mixtures

Homogeneous mixtures have a uniform composition and appearance, meaning that the different components are not distinguishable. In contrast, heterogeneous mixtures contain visibly different substances or phases, allowing for the identification of individual components. Understanding this distinction is crucial for classifying mixtures correctly.