Unit 1 Classifying Matter Notes

Flow chart

Pure Substances (elements and compounds) 1. EVERY SAMPLE of a given pure substance has EXACTLY THE SAME characteristic properties. a. Boiling point Freezing point Melting point Density 2. Can NOT BE SEPARATED by PHYSICAL means   Ex: water always has a boiling point of 100 C, melting point of 0 C, freezing point of 0 C and a density of l.00 g/ml. Other pure substances have their own individual characteristics (bp, mp, fp, density)

Mixture – Not the same as a compound. Usually composed of several substances. CAN be separated by PHYSICAL means 2 kinds of mixtures

1.Homogeneous mixtures – also called solutions have the same composition throughout. Ex: salt water

How Solutions are Made…

2. Heterogeneous mixtures – the composition is NOT the same throughout; Ex: blue cheese dressing, sand and water, trail mix

Learning Check Learning Check: Identify the following as pure substances (p) or mixtures (m): ___ Oxygen (O2) ___ Lemonade ___ Snickers bar ___ Distilled water ___ Dry ice ___ Soil P M M P P M

Learning Check Learning Check: Classify the following as Homogeneous (ho) or Heterogenous mixtures (he) ___ Pure Air ___ Salsa ___ Chocolate chunk ice cream ___ Ink ___ Blood ___ Chicken noodle soup Ho He He Ho Ho He

Physical Separation: Separates MIXTURES 1.Distillation – based on differences in boiling point: separating a mixture of alcohol and water. Alcohol has a lower boiling point than water so it will boil off sooner. Both substances will be retained

Physical Separation: Separates MIXTURES 2.Filtration – based on differences in solubility and particle size -liquid is passed through materials with very small holes to strain out particles.

Physical Separation: Separates MIXTURES 3.Chromatography – based on differences in polarity Example Video

Physical Separation: Separates MIXTURES 4.Magnetism – separating iron and sand

Chemical Separation: Separates COMPOUNDS Electrolysis – a method of separating compounds (pure substances). This is NOT a physical separation, but a chemical separation using electricity. Waterhydrogen + oxygen

Learning Check Which method would be appropriate for separating these mixtures?   _______________ Sawdust and water _______________ Nails and dirt _______________ Water and vinegar Filtration Magnetism Distillation