MIXTURES AND PURE SUBSTANCES

1. Chemical Procedures
2. Physical Procedures

Nota:

• Can be separated into their different component substances by physical change

1. HETEROGENEOUS

   Nota:

   • We can easily see that it is composed of different substances
2. HOMOGENEOUS

   Nota:

   • We cannot easily see that it is composed of diferent substances.
   1. SOLUTIONS

      Nota:

      • It is a homogeneous mixture that is formed of different amounts of two or more puere substances.
      1. SOLVENT

         Nota:

         • It's the main component in a solution; it is usually a liquid but not necessary
      2. SOLUTE

         Nota:

         • It is the dissolved substance in a solution.
3. SEPARATION TECHNIQUES
   1. DECANTING

      Nota:

      • Is used to separate liquids with different densities that are not mutually soluble (inmmiscible).
   2. FILTRATION

      Nota:

      • Is used to separate an undissolved solid from a liquid. The mixture is passed through filters
   3. MAGNETIC ATTRACTIONS
   4. SIFTING

      Nota:

      • Is used to separate mixtures of powdered solids into different sized particles
   5. PRECIPITATION

      Nota:

      • Is used to remove solid solutes from a liquid solution
   6. CRYSTALLISATION

      Nota:

      • A solution is heated and then slowly cooled, or the solvent is evaporated off. Particles of a homogeneous solute (pure substance) gradually form crystals at the bottom of the container.
   7. DISTILLATION

      Nota:

      • It is used to saparate mutually soluble liquids in a solution. When the solution is heated and boils, the liquids separate because they have different boiling points.

1. Characteristic Properties
   1. Melting Point

      Nota:

      • It's the temperature at which a pure substance in solid state changes into a liquid. For each substance, this is the same at the freeezing point.
   2. Boiling Point

      Nota:

      • Is the temperature at which a pure substance in a liquid state changes into gas. For each substance, this is same at the condensation point.
   3. Density

      Nota:

      • It is the ratio of a pure substance's mass to its volumen. Density is constant in all states.
2. ELEMENTS

   Nota:

   • It is a pure substance that cannot be broken down into a simpler substance.
3. COMPOUNDS

   Nota:

   • It ias a pure substance composed of two or more elements. These elements are always combined in fixed proportions. It can be broken down into simpler, pure substances ( other compounds, elements or both) by chemical change.