1.1A Elements, Compounds and Mixtures

Tell me about Elements

a single pure substance, made of only one type of atom.

• Atoms of an element are all the same as each other (except for isotopes)

• Atoms of an element are different than atoms of another element

• Each element is denoted by a chemical symbol

Tell me about Compounds

• Compounds contain fixed proportions/ratios of elements, held together by chemical bonds

• Different physical and chemical properties compared to their constituents

Na Cl₂ NaCl

Reactive Toxic Edible

Metal Gas Solid

Tell me about Mixtures. What are the two types of Mixtures?

composed of two or more substances in which no chemical combination has occurred

• Components have different physical and chemical properties

• Composition of mixture is not fixed

1. Homogenous

2. Heterogenous

Tell me about Homogenous Mixtures

Uniform composition and properties

• If you take a sample from anywhere in the mixture, you would have the same properties

Tell me about Heterogenous Mixtures

• Non-uniform composition, properties are not the same throughout

• It is usually possible to separate components of heterogenous mixtures

What are the methods of Separating Components?

Filtration: process in which solid particles in a liquid are removed through the use of a filter that allows the fluid to pass through but not the solid

Recrystallization: a substance is separated from others by dissolving the mixture in a solvent and then crystalizing the desired substance from the solution

Distillation: components of a liquid mixture are separated through selective boiling and condensation

Paper Chromatography: separates components of a mixture based on adsorption to a solid phase