Answers to First Worksheet


                                                                         

1. What is Chemistry ?   Chemistry is the science of substances.          
Substances (chemicals) make up the forms of matter - gases,               
liquids and solids.

2. There are two kinds of materials, pure substances and                  

  mixtures.

3. Describe what occurs when vinegar is added to baking
  soda.
    Extensive bubbling occurs as the result of the production of
    a gas, carbon dioxide.  Two other products are also produced
    in this reaction, sodium acetate and water.

4. Describe what occurs when sugar is heated.
    The sugar darkens in color and steam is produced.  This is
    an example of a chemical decomposition in which a single
    reactant, sugar, is decomposed into two products, carbon
    and water.

5. If a pure substance CAN NOT be decomposed it is called

  a/an element.

6. If a pure substance can be decomposed it is called

  a/an compound.

7. If a mixture has the same appearance as a pure substance, it

  is called a solution.

8. If a mixture has nonuniform properties, it is called

  a heterogeneous mixture.

9. Give four examples of each of the following materials.

   a) element - oxygen, iron, copper, carbon, hydrogen, etc.

   b) compound - water, salt, baking soda, sugar, etc.
                                                                         
   d) heterogeneous mixture - soil, concrete, wood, banana
      split, etc.