Final answer:
Each substance is classified based on its composition: Salt, pure water, carbon dioxide, and table sugar are compounds; soil and ranch dressing are heterogeneous mixtures; salt water, pure air, and white wine are homogeneous mixtures; and gold and mercury are elements.
Step-by-step explanation:
To classify each substance as an element, a compound, a homogeneous mixture, or a heterogeneous mixture, let's consider each one:
- Salt - Compound (NaCl, sodium chloride)
- Pure water - Compound (H2O, water)
- Soil - Heterogeneous mixture (different substances that retain their individual properties)
- Salt water - Homogeneous mixture (solution of salt in water where the composition is uniform)
- Pure air - Homogeneous mixture (It mainly consists of nitrogen and oxygen gases evenly mixed)
- Carbon dioxide - Compound (CO2, a chemical composition with two oxygen atoms covalently bonded to a single carbon atom)
- Gold - Element (Au, atomic number 79)
- Bronze - Homogeneous mixture (an alloy of copper and tin)
- White wine - Homogeneous mixture (solution of compounds in water)
- Mercury - Element (Hg, atomic number 80)
- Ranch-style salad dressing - Heterogeneous mixture (various ingredients that are not uniformly distributed)
- Table sugar (sucrose) - Compound (C12H22O11, a molecule composed of carbon, hydrogen, and oxygen in a fixed ratio)
An element is a pure substance made up of only one kind of atom. A compound is a substance formed from two or more elements chemically bonded in a fixed ratio. A homogeneous mixture (or solution) is a mixture with a uniform composition throughout, whereas a heterogeneous mixture is one where the components are easily distinguishable.