Final answer:
Substances can be classified as elements if they are composed of a single type of atom and as compounds if composed of two or more types of atoms chemically bonded together. Examples include sulfur and potassium as elements and water and carbon dioxide as compounds.
Step-by-step explanation:
To classify substances into elements or compounds, it's important to understand that an element is a pure substance that cannot be broken down into simpler substances by chemical means, while a compound is a substance that consists of two or more different elements that are chemically bonded together in a fixed ratio.
- Sulfur is an element because it consists of only one type of atom.
- Water (H₂O) is a compound as it is composed of hydrogen and oxygen atoms bonded together.
- Carbon dioxide (CO₂) is also a compound, made up of carbon and oxygen atoms.
- Oxygen (O₂) is a molecular element, as it consists of molecules made from two oxygen atoms.
- Potassium (K) is an element, represented by one type of atom.
In the context of classifying various substances:
- Salt (NaCl) is an ionic compound.
- Pure water (H₂O) is a molecular compound.
- Soil is generally considered a heterogeneous mixture as it can contain various organic matter, minerals, gases, liquids, and countless organisms.
- Salt water is a homogeneous mixture or solution because the salt is completely dissolved in the water.
- Pure air is a homogeneous mixture of gases.
- Carbon dioxide (CO₂) is a molecular compound.
- Gold (Au) is an element.
- Bronze is a homogeneous mixture because it is an alloy of copper and other metals such as tin.