Answer: When a substance is pure, it is composed of one type of molecule. For example, table salt is only composed of (more or less) salt molecules, while seawater has water and salt molecules. A more complicated example of a non - pure substance is soil. It has many different types of nutrients and compounds.
Something that contains only one kind of matter. This can either be one single element or one single compound, but every sample of this substance that you examine must contain exactly the same thing with a fixed, definite set of properties.
The surface metabolism model evokes mineral
catalysts. Surface metabolism model dissolved gases in contact with
minerals lining the walls of the deep-sea hydrothermal vents and formed more
complex, organic molecules while Prebiotic soup model is molecules in
atmosphere or from meteorites condensed in the ocean which led to the formation
of more complex molecules.
The advantage of steam distillation over simple distillation is that the lower boiling point reduces decomposition of temperature -sensitive compounds.