what are pure substances
pure substances are elements or compounds, mixed with nothing.
A pure substance is anything that contains the same kind of atoms (if an element) or the same kind of molecules (if a compound).
Pure substances are substances that are made up of only one type of particle or molecule. These substances have a fixed composition and distinct chemical properties. There are two main types of pure substances: elements and compounds.
1. Elements: Elements are the simplest form of pure substances and cannot be broken down into simpler substances by chemical means. They consist of only one type of atom. Examples of elements include oxygen, carbon, hydrogen, and iron.
2. Compounds: Compounds are pure substances composed of two or more elements chemically combined in fixed proportions. Unlike elements, compounds can be broken down into their constituent elements through chemical reactions. Examples of compounds include water (H2O), carbon dioxide (CO2), and sodium chloride (NaCl).
To determine if a substance is a pure substance, you can perform the following steps:
1. Examine the substance for any visible impurities, such as particles or foreign matter. If the substance appears uniform and does not contain any impurities, it is likely a pure substance.
2. Analyze the substance's chemical composition using laboratory techniques. This can involve techniques like spectroscopy, chromatography, or elemental analysis. By understanding the types and proportions of atoms present in the substance, you can determine if it is a pure substance or a mixture.
3. Study the substance's physical and chemical properties. Pure substances have consistent properties, such as fixed boiling and melting points, specific densities, and characteristic reactions with other substances.
It is important to note that mixtures, which consist of two or more substances physically combined but not chemically bonded, are not considered pure substances.