Page 57 - Science Class 08

F. Very short answer ques ons.
Write the correct name for:

1. the mixture of nitric acid and hydrochloric acid : __________________________
2. the science that aimed at making gold ar ficially : __________________________
3. fine par cles of gold obtained during its extrac on : __________________________
4. the metal mixed in gold to make ornaments : __________________________
5. an sep c prepared free iodine for wounds : __________________________
6. the metal mixed with copper to make bronze : __________________________

G. Short answer ques ons.
1. Write short notes on:
(a) noble gases (b) noble metals (c) purity of gold
2. What are metals and non-metals?
3. What is gold?
4. Write the uses of pla num.
5. Write about the chemical proper es of non-metals.
6 Write a short note on alloys.

H. Long answer ques ons.
1. What is meant by noble metals? Why are they called so? Write in detail about the
extrac on, proper es and use of gold.
2. What do you know about the occurrence, extrac on, proper es and use of pla num?
3. What do you know about the occurrence, extrac on, physical proper es, chemical
proper es and use of non-metals?
4. What is an alloy? How are alloys formed and how are they useful? Name five important
alloys made by using iron as the base metal.

Project ActivityActivityActivity
Project
Project
Project Activity
A. Collect pictures of three noble metals and paste them in your scrapbook.
B. Complete the following table.

Proper es Metal Non-metals

Physical Lustrous
High mel ng and boiling points
Not sonorous
Solids at room temperature

Chemical Form oxides or hydroxides with water Do not react with dilute acids
Non-metals form hydrides when they
react with hydrogen
More reac ve metals displace less
reac ve metals from their salt solu ons
Form acidic oxides when they react with
oxygen

Science-8 57