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Mixtures & Compounds

The release of atom power has changed everything except our way of thinking...the solution to this problem lies in the heart of mankind. If only I had known, I should have become a watchmaker


Albert Einstein

MIXTURES

Combination of two or more substances that are not chemically combined

    • No new substance formed
    • Do not exist in fixed proportions to each other
    • They just mix
    • Most natural substances are mixtures
    • Can be physically separated into pure compounds or elements
    • Can be separated by mechanical means
    • Physical properties can change
    • Any combination of solid, liquid or gas can be a simple mixture

MIXTURES MAY BE HOMOGENEOUS OR HETEROGENEOUS

Homogeneous Mixtures:

  • The prefix: "homo"- indicates the same
  • Have the same uniform appearance and composition throughout

SOLUTIONS are homogeneous mixtures:

  • A solution is a mixture of two or more substances in a single phase
  • At least two substances must be mixed in order to have a solution
  • The substance in the smallest amount and the one that DISSOLVES is called the SOLUTE
  • The substance in the larger amount is called the SOLVENT - it does the dissolving
  • IN most common instances water is the solvent
  • The gases, liquids, or solids dissolved in water are the solutes

COLLOIDS are another type of homogeneous solutions with a bigger particle size

  • Colloid particles may be seen in a beam of light such as dust in air in a "shaft" of sunlight
  • Milk, fog, and jello are examples of colloids

Heterogeneous Mixtures:

  • The prefix: "hetero"- indicates difference
  • A heterogeneous mixture consists of visibly different substances or phases
  • The three phases or states of matter are gas, liquid, and solid
  • A SUSPENSION is a heterogeneous mixture of large particles
  • These particles are visible and will settle out on standing
  • Examples of suspensions are: fine sand or silt in water or Italian salad dressing

 

PURE COMPOUNDS

 A pure compound has the same elements and the same amount of elements all of the time

    • Elements are chemically combined
    • Compound properties are different from the properties of the elements
    • They cannot be separated physically
    • Physical properties such as boiling point or melting point of pure substances are do not change

COMPARE & CONTRAST MIXTURES & COMPOUNDS

Mixture

Compound

Not chemically combined

Combine chemically, forming molecules

Can combine in any proportion

Combine in set proportions

Separated physically

Separated chemically

 

 

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