Classification of Mixtures and Substances

Classification of Mixtures and Substances

• Sand & salt mixture is considered heterogeneous due to the visible differences in composition.
• Salt water is classified as homogeneous since its components (salt and water) are uniformly dissolved.
• Pure water is a pure substance since it contains only H2O molecules without any impurities.
• A tossed salad is heterogeneous because the different ingredients (vegetables, dressing, etc.) can be distinguished visually.
• Hydrogen is categorized as a pure substance; it is a diatomic molecule consisting solely of H2.
• Unfiltered air is homogeneous, as it consists of a mixture of gases (like nitrogen and oxygen) that are uniformly mixed.
• An apple is heterogeneous because its internal structure (seeds, flesh, skin) can be identified.
• Granite is also heterogeneous; it is an igneous rock composed of various minerals that can be distinguished.
• Iron is a pure substance composed only of iron atoms, indicating high purity.
• Iron with rust is classified as heterogeneous; rust (iron oxide) appears distinctly from pure iron.
• Nitric acid is homogeneous as it features a uniform mixture of nitrogen, oxygen, and hydrogen atoms in solution.
• Wood is heterogeneous due to its varied structure; it includes distinct fibers, cells, and natural variation.