Available Answers

1. 1.

   Name the following.

   1. The element whose symbol is S.
   2. The element whose symbol is Cl
   3. An element whose symbol is W
   4. The element whose symbol is C
   5. Number of elements found so far in the nature
2. 2.

   Write T for True and F for False.

   1. The symbol of an element represents one molecule of that element.
   2. The symbol of phosphorus has been derived from its Latin name.
   3. The chemical symbol of gold is Au, derived from its Latin name - Aurum.
   4. Atoms of an element cannot form molecule of that element.
   5. An element is not a pure substance.
3. 3.

   Classify the following as elements or compounds.

   Iron	Rust	Aluminium
   Calcium oxide	Copper	Calcium sulphate
   Sodium hydrogen carbonate	Sodium chloride	Lead
   Zinc	Lead  sulphide	Sodium chloride
   Water	Carbon dioxide	Plaster of Paris
   Helium	Nitrogen	Hydrogen
   Sodium	Potassium oxide	Galena

    

4. 4.

   Classify the following chemical formulas as element or compound.

   Au	Fe2O3	H2
   CaCO3	Cl2	Ne
   H2CO3	CuO	C6H12O6
   P4	S8	H2SO4

    

5. 5.

   Classify each of the following as homogeneous mixture, heterogeneous mixture, alloy, solution, suspension or emulsion.

   1. Honey	2. Flavoured milk
   3. Steel	4. A pack of coloured pencils
   5. Soil	6. Sand and salt in a pan with popcorns
   7. Chalk and water	8. Kerosene oil and water
   9. Egg yolk	10. Butter

    

6. 6.

   Observe the figure and answer the questions.

   

   1. Label the diagram.
   2. What is the role of B and C?
   3. What is the purpose of the setup shown in the figure?
   4. How does it differ from the setup of the distillation unit?
   5. Why are there inlet and outlet of water?