MIXTURES AND PURE SUBSTANCES

MIXTURES AND PURE SUBSTANCES

1. Procedures

   • Chemical Procedures
   • Physical Procedures

2. MIXTURES

   • Can be separated into their different component substances by physical change
   • HETEROGENEOUS
     • We can easily see that it is composed of different substances
   • HOMOGENEOUS
     • We cannot easily see that it is composed of diferent substances.
     • SOLUTIONS
       • It is a homogeneous mixture that is formed of different amounts of two or more puere substances.
       • SOLVENT
         • It's the main component in a solution; it is usually a liquid but not necessary
       • SOLUTE
         • It is the dissolved substance in a solution.
   • SEPARATION TECHNIQUES
     • DECANTING
       • Is used to separate liquids with different densities that are not mutually soluble (inmmiscible).
     • FILTRATION
       • Is used to separate an undissolved solid from a liquid. The mixture is passed through filters
     • MAGNETIC ATTRACTIONS
     • SIFTING
       • Is used to separate mixtures of powdered solids into different sized particles
     • PRECIPITATION
       • Is used to remove solid solutes from a liquid solution
     • CRYSTALLISATION
       • 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.
     • DISTILLATION
       • 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.

3. PURE SUBSTANCES

   • Characteristic Properties
     • Melting Point
       • 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.
     • Boiling Point
       • 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.
     • Density
       • It is the ratio of a pure substance's mass to its volumen. Density is constant in all states.
   • ELEMENTS
     • It is a pure substance that cannot be broken down into a simpler substance.
   • COMPOUNDS
     • 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.