Final answer:
A pure substance is either an element or a compound, while a mixture can be homogeneous if it is uniform throughout, or heterogeneous if it is not. Examples include salt and pure water as compounds, soil as a heterogeneous mixture, and salt water as a homogeneous mixture.
Step-by-step explanation:
To classify substances into the correct category, it is essential to know whether a substance is chemically pure. Pure substances are either elements or compounds, whereas mixtures are either homogeneous or heterogeneous based on their uniformity. Let's consider a list of substances to clarify this:
- Salt (Sodium chloride): A pure substance and a compound because it consists of more than one type of atom chemically bound together.
- Pure water (H₂O): A pure substance and a compound, comprised of hydrogen and oxygen atoms in a fixed ratio.
- Soil: A heterogeneous mixture because its composition is not uniform throughout.
- Salt water: A homogeneous mixture (solution) as the salt is evenly distributed through the water.
- Pure air: A homogeneous mixture of different gases, primarily nitrogen and oxygen, with small amounts of other gases.
- Carbon dioxide (CO₂): A pure substance and a compound made up of carbon and oxygen atoms in a definite proportion.
- Gold (Au): A pure substance and an element because it contains only one type of atom.
- Bronze: A homogeneous mixture, being an alloy of copper and tin or other elements.
For individual examples such as:
- White wine: A homogeneous mixture, as it appears uniform throughout.
- Mercury (Hg): A pure substance and an element since it consists of one type of atom.
- Ranch-style salad dressing: A heterogeneous mixture because its ingredients are not uniformly distributed.
- Table sugar (sucrose): A pure substance and a compound composed of carbon, hydrogen, and oxygen atoms.