Classification of Matter

Element Pure substance Made of same type of atoms Cannot be separated into simpler substances by chemical or physical changes always has same properties as another pure sample Example: copper wire

Compound Made of two or more different elements chemically combined Example: H2O Follows Law of Definite Proportions Elements making up the compound are combined in a definite proportion by mass Percent composition of elements in the compound are always the same % comp = mass of element x 100% mass of compound

Practice Problem In 100 g sample of water, there is 11.2 g of Hydrogen and 88.8 g of Oxygen, what is the percent composition of oxygen in water?

Chemical and physical properties of a compound differ from those of the elements that it is made up from Water: liquid at room temperature; puts out fires Hydrogen: gas at room temperature; flammable Oxygen: gas at room temperature; flammable

3. Mixtures consist of parts that have different properties Consists of two or more substances that each retain their own individual properties 3 ways formed: 2 or more elements mixed together Mixture of copper and nickel coins A compound and element mixed together 2 or more compounds mixed together Mixture of sugar and salt

Properties of Mixtures Mixture retains properties of each of the different parts of the mixture Composition of mixture varies Not equal proportion of elements or compounds by mass in a mixture Example: Bag of fruit snacks

Types of Mixtures Homogenous sample from one part of mixture has the same composition as a sample from any other part of the mixture Example: Ketchup, perfume, shampoo

Solutions Homogenous mixture 2 parts: Example: Salt water Solute: substance that gets dissolved Solvent: substance in which the solute gets dissolved Example: Salt water Salt = solute Water = solvent

Heterogeneous Sample of matter that has parts with different compositions Throw salt on top of sugar – not equal composition throughout mixture Example: italian dressing

Separating Mixtures Filtration Distillation Chromatography Use porous barrier to separate a solid from a liquid Distillation Separates liquids with different boiling points Chromatography Separates different components as moves across the surface of another material Crystallization Formation of pure solid from a solution