Elements, Compounds and Mixtures. Flashcards
What is an element?
A substance that consists of one type of atom joined together. Elements exist as the same atoms or molecules.
What is a compound?
A compound is a substance consisting of atoms of two or more different elements, chemically joined together in fixed proportions. Compounds can be molecules or ionic structures.
What is a mixture?
A mixture contains two or more elements or compounds that are not chemically joined together. Mixtures are impure substances. Mixtures can be separated through physical processes.
What is a pure substance?
A substance containing only one element or compound. Most substances are mixtures, as they contain different elements/compounds.
How would the results on a graph, depicting the temperature of a substances state change/melting point, show whether that substance is pure or impure?
The substance would have a sharp melting point, shown by a horizontal line on a graph. A mixture would melt over a range of temperatures (more than one horizontal line).
