What is the difference between a compound and a mixture

Pure substances have a sharp melting point but mixtures melt over a range of temperatures. This difference is most easily seen when the temperature of a hot liquid is measured as it cools and freezes. The graph shows the cooling curve for a sample of a compound called salol.

The horizontal part of the graph shows that the salol has a sharp melting point, so it is pure. Impure salol a mixture of salol and other substances would produce a gradual decrease over a range of temperatures as it freezes. Pure substances and mixtures The meaning of pure The word 'pure' is used in chemistry in a different way from its everyday meaning. In chemistry: a pure substance consists only of one element or one compound a mixture consists of two or more different substances, not chemically joined together The components of a mixture can be separated without chemical reactions Mixtures and compounds Hydrogen and oxygen are both gases.

Mixture Compound Composition Variable composition - the relative amounts of the two gases can be changed. Constant composition - water always contains the same ratio of hydrogen to oxygen.

This ratio is shown in the chemical formula of the compound - H 2 O. Joined or not? What is the difference between mixtures and compounds? Ernest Z. Jan 28, Explanation: Try watching this video: A compound always has the same composition. Related questions How do I determine the molecular shape of a molecule? What is the lewis structure for co2? What is the lewis structure for hcn? How is vsepr used to classify molecules?

What are the units used for the ideal gas law? How does Charle's law relate to breathing? What is the ideal gas law constant? Mixtures are made of two or more substances — elements or compounds — that are mixed physically but not chemically; they do not contain any atomic bonds.

Compounds are made up of elements, which are pure substances with only one kind of atoms. Atoms of the elements form bonds to combine and make up a molecule of the compound. The compound contains a uniform distribution of these molecules. A compound has different physical and chemical characteristics than its component elements. It is not possible to see the elements when you see the compound. Salt is made of sodium and chloride but the physical and chemical properties of salt are completely different from those of sodium or chloride.

Both elements and compounds are called pure substances because they contain only one type of molecule. A mixture contains two or more types of pure substances. The molecules of these substances do not form any chemical bonds in a mixture.

Components of a mixture retain their chemical independence but physically blend into each other. It is often possible to see these components and differentiate them visually.

The component elements of a compound can only be separated via a chemical reaction that breaks the atomic bonds that bind its molecules. The ingredients of a mixture may be separated by physical means like sedimentation or decantation. Share this comparison:. If you read this far, you should follow us:. Diffen LLC, n. Comparison chart Compound versus Mixture comparison chart Compound Mixture Definition A compound contains atoms of different elements chemically combined together in a fixed ratio.