GSEB Solutions for Class 8 Science and Technology – Metal – Non Metal (English Medium)
GSEB SolutionsMathsScience
Exercise 22:
Solution 1(a):
Iron, Aluminium, Copper will show lustre as they are metals.
Exercise 23:
Solution 1(a):
Iron nail and aluminium wire become flat while coal, a lead pencil, and carbon rod turn into pieces on hammering.
Exercise 25:
Solution 1(a):
Red litmus paper turns blue when it is immersed in the solution of water and ash from the magnesium strip.
Exercise 27:
Solution 1(a):
Red litmus shows no colour change but blue litmus paper turns red when it is immersed in the solution of water and gas from sulphur.
Exercise 28:
Solution 1(a):
Iron: Used for making nails, nuts, bolts, tools, pins, machines etc.
Copper: Used for making electric wires, vessels, electric gadgets etc.
Gold & Silver: Used for making jewellery, coins, medals etc.
Aluminium: Used in vehicles, wires, for packing food, machines, utensils, furniture etc.
Sodium: Used as common salt and in the preparation of many chemicals.
Potassium: Important for many body functions and useful in various chemical reactions.
Mercury: Used in thermometers, barometers, electric switches etc.
Exercise 31:
Solution 1.1:
True
Solution 1.2:
False. Wires cannot be drawn from coal as it is a non-metal. It can be drawn from copper, aluminium.
Solution 1.3:
True
Solution 1.4:
True
Solution 1.5:
False. Chemical formula is same as molecular formula but not same as chemical structure.
Solution 2:
| Element | Use |
| Mercury | in the thermometer |
| Carbon | as a fuel |
| Gold | preparing ornaments |
| Iron | in the preparation of machinery |
| Aluminium | for the conduction of electricity and for making utensils |
Exercise 32:
Solution 3.1:
- Many metals like iron, copper, steel and aluminium are used to make containers, machines.
- Gold, silver and platinum metals are used to make jewellery due to their hard and shiny appearance.
Solution 3.2:
Phosphorus is used to prepare match sticks, crackers explosives, insecticides.
Solution 3.3:
NaCl: Sodium Chloride
Solution 3.4:
Ionization is the process by which an atom or a molecule acquires a negative or a positive charge by gaining or losing electrons to form ions.
Solution 3.5:
The chemical process in which either oxygen is removed or hydrogen is added is known as reduction.
Solution 4:
In the given reaction, oxygen gets separated from CuO and is added to H2. So, CuO undergoes reduction to form Cu and H2 undergoes oxidation to form H2O.
Solution 5:
Metals are used in the making of machinery, automobiles, aeroplanes, trains, satellites, industrial gadgets, cooking utensils, water boilers etc.
Non-metals are essential for our life which all living beings inhale during breathing, in fertilizers, to enhance the growth of plants, used in water purification, medicines etc. Due to this, metals and non-metals are important factors in our life.