1. Define the following:
(a) Variable Valency
(b) Chemical Equation
(c) Symbol
(d) Balanced equation
(e) Valency
2. Differentiate between
(a) Ion and Radical
(b) Word equation and molecular equation
3. State any two information that are provided by a chemical equation
4. State the reason why an equation needs to be balanced
5. State the limitations of a chemical equation with respect to
(a) The conditions which effect the chemical reaction
(b) The progress of the Chemical reaction
6. State the Valencies of the followings:
(a) Aluminium
(b) Calcium
(c) Bicarbonate
(d) Dichromate
7. Write the molecular equation for the following word equation:
(a) Copper Carbonate → Copper oxide + Carbon –di-Oxide
(b) Zinc + Sodium hydroxide → Sodium Zincate + hydrogen
(c) Aluminium + Sulphuric Acid → Aluminium Sulphate + Hydrogen
8. Name the Following:
(a) Three atoms of hydrogen combines with one atom of Nitrogen to form……………..
(b) Substances which takes part in chemical reaction are called ……………………..
(c) Elements classified systematically in a table called ………………..
(d) Valency one elements are said to be …………….
(e) An element that has variable valency 4 & 6…………………
9. Fill in the Blanks:
(a) In the equation 2 Ag2O --> 4Ag + O2 The atoms of the elements silver and of oxygen are …………………. Hence the equation is …………………
(b) An equation must be balanced to comply with the law of ………………..
(c) In the equation 2KClO3 --> 2KCl+O2 the atom of the element ………………… is not balanced
(d) The positively charged ions are called …………………
(e) Element is a………………… substance which is made up of one kind of Atom
(f) An Atom of any element is denoted by a ………………….
(g) Atom is the basic unit of a/an ………………….
(h) The valency of all metals are considered ……………………..
(i) While writing the chemical formula the…………………. ion is written first