2 Pure Substance Pure substance: has only one type of component. Example- waterMatter can be pure, or it can be two or more substances mixed togetherExample- silver jewelry
3 Atoms Elements Compounds Molecules Pure SubstancesA substance is pure if it contains only a single type of atom or a single combinations of atoms that are bonded togetherAtomsElementsCompoundsMolecules
4 Elements Substance that contains only a single type of atoms Cannot separate into other substance
5 CompoundsSubstance that consists of two or more different types of atoms bonded togetherExample: water, salt, carbon dioxideMade of elements in a specific ratiothat is always the sameHas a chemical formulaCan only be separated bychemical means, not physicallyH2ONaClCO2
6 MixturesCombination of different substances that remain the same individual substances and can be separated by physical meansExample: mix of apple and oranges and bananasEach item retains itsproperties in the mixtureDoes not always containthe same amount of thevarious substanceChem4kids.com
7 MixturesHeterogeneous mixture: can see all the different parts of the mixtureExample: handful of soil that contains rocks, dirt, and insectsChem4kids.com
8 MixturesHomogeneous mixture: substance is evenly spread throughout the mixtureExample: salt waterChem4kids.com
9 Can you identify the following? You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture.Review:An element contains just one type of atom.A compound contains two or more different atoms joined together.A mixture contains two or more different substances that are only physically joined together, not chemically.A mixture can contain both elements and compounds.