A Matter of FactA Matter of Fact

Mixtures, Elements and Mixtures, Elements and CompoundsCompounds

Adapted from: education.jlab.org/jsat/.../elements_compounds_mixtures.ppt

Mixtures, elements, Mixtures, elements, compoundscompounds

Scientists like to classify things.Scientists like to classify things. One way that scientists classify One way that scientists classify

matter is by its composition or matter is by its composition or structure.structure.

Ultimately, all matter can be Ultimately, all matter can be classified as mixtures, elements and classified as mixtures, elements and compounds.compounds.

Why isn’t it a good idea to Why isn’t it a good idea to classify matter by its classify matter by its

phases?phases?

Because one kind of substance can exist in Because one kind of substance can exist in more than one phase – such as Hmore than one phase – such as H220. And 0. And matter changes phases rather easily.matter changes phases rather easily.

Scientists ask themselves these Scientists ask themselves these questions?questions? Is the matter uniform throughout?Is the matter uniform throughout? Can it be separated by physical Can it be separated by physical

means?means? Can it be separated by chemical Can it be separated by chemical

means?means?

By asking these questions scientists By asking these questions scientists can classify matter into three can classify matter into three categories: Mixtures, Elements, or categories: Mixtures, Elements, or Compounds. Compounds.

MixturesMixtures – two or more substances that are – two or more substances that are not chemically combined with each other and not chemically combined with each other and can be separated by physical means. can be separated by physical means.

The substances in a mixture retain their The substances in a mixture retain their individual properties.individual properties.

Mixtures are either heterogeneous or Mixtures are either heterogeneous or homogeneoushomogeneous

HeterogeneousHeterogeneous mixtures are mixtures are not even not even throughoutthroughout like salad, pizza, or Ocean water. like salad, pizza, or Ocean water.

HomogenousHomogenous mixtures are mixtures are even throughout even throughout like milk, blood, or Gatorade like milk, blood, or Gatorade All homogenous mixtures are solutions All homogenous mixtures are solutions

because a substance (a solute) dissolves in because a substance (a solute) dissolves in another (a solvent) creating the another (a solvent) creating the homogenous solution.homogenous solution.

ElementsElements – simplest form of pure – simplest form of pure substance. They are made of only substance. They are made of only one type of atom and they cannot be one type of atom and they cannot be broken into anything else by physical broken into anything else by physical or chemical means.or chemical means.

If it is on the Periodic Table then it is If it is on the Periodic Table then it is an element.an element.

CompoundsCompounds – pure substances that – pure substances that are made of two or more elements are made of two or more elements that have combined during a that have combined during a chemical reaction. chemical reaction.

Compounds can be broken into Compounds can be broken into simpler substances only by chemical simpler substances only by chemical means.means.

Examples of compounds are water, Examples of compounds are water, hydrogen peroxide, and salthydrogen peroxide, and salt

You can determine what a You can determine what a substance is by asking substance is by asking

questions and using a flow questions and using a flow chart method.chart method.

Pure Substance

Element Compound

Homogonous

Heterogeneous

Mixture