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Objectives. To learn to distinguish between mixtures and pure substances To learn methods of separating mixtures. A. Mixtures and Pure Substances . Matter can be classified as a mixture or a pure substance. . Water is a compound. All the components are the same—H 2 O molecules.
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Objectives • To learn to distinguish between mixtures and pure substances • To learn methods of separating mixtures
A. Mixtures and Pure Substances • Matter can be classified as a mixture or a pure substance.
Water is a compound. All the components are the same—H2O molecules. A. Mixtures and Pure Substances Pure Substances • A pure substance always has the same composition. • Pure substances are of two types: • Elements which cannot be broken down chemically into simpler substances • Compounds in which all the components are the same (but could be chemically broken down into elements)
A. Mixtures and Pure Substances Mixtures • A mixture has variable composition • A homogeneous mixture has the same properties throughout. Often called a solution • A heterogeneous mixture has different properties in different parts of the mixture.
B. Separation of Mixtures Mixtures can be separated into pure substances by various means. • distillation
An Oil Refinery uses Distillation to separate crude oil into useful fractions
B. Separation of Mixtures Mixtures can be separated into pure substances by various means. • filtration
Separation Techniques • How would you separate…..? • Two liquids that boil at different temperatures • Sand and water • Oil and iron filings • Oil and paper • Stones and peanuts • A pile of sticks and dry leaves • A mixture of dogs and cats