Enfant India International school
Class -8th
Sub.- Chemistry M.M.-20
Section -A
1. Fill in the blanks:. (1×5=5)
(a) The symbol of aluminum is __________ .
(b) The valency of nitrogen is _________ .
(c) Elements combine with their own atoms in a fixed number are called their ________ .
(d) The short form of an element is called _________.
(e) Carbon dioxide has atom of carbon and ______ atoms of oxygen.
2. Write
the molecular formula of. (1×5=5)
(a) Cuprous oxide
(b) Calcium oxide
(c) Nitric acid
(d) Iron sulphide
(e) Ammonium hydroxide
Section -B
3. Define
the following:. (1×5=5)
(a) Oxides
(b) Neutral oxides
(c) Oxidising agent
(d) Reducing agent
(e) Chemical reaction
4. Answer
these questions:. (1×5=5)
(a) Define chemical reaction.
(b) What is a redox reaction ? Explain
With the help of an example.
( C) What is meant by symbol ?
(d) Calculate the valency of sulphur and chlorine.
(e) State law of conservation of mass .
