1Write the difference between baking soda and common salt.
2Write the difference between soap and detergent.
3Name four chemicals used as food materials and give two uses of each in a table.
4Which chemicals are used for cleaning? Name any four and write what each is used for.
5Why is baking soda used when making bread, cookies and rice bread?
6Name any two chemical substances used in your own kitchen and write what they are used for.
7Doctors advise washing hands with soap and water from time to time and using sanitiser to stay safe from the coronavirus and other viruses. Why?
8If the toilet in your school has many stains and a bad smell, what advice would you give to the person who cleans it?
9Ink from a ballpoint pen has marked your friend's clothes, and washing with soap and water again and again has not removed it. What should be done? Give your friend your advice.
10What effect does the unnecessary use of sugar, baking soda and salt have on human health?
11Write the difference between metals and non-metals.
12Write the difference between malleability and ductility.
13What is a metal? State any three properties by which a metal can be recognised.
14How can you decide that a given object is a non-metal? Answer on the basis of any two properties.
15Which two properties of metals make it possible to make cooking vessels from them?
16Write two uses each of iron, copper and gold.
17Explain briefly how the careless disposal of everyday materials affects the environment.
18News sometimes reports that lead has been mixed into petrol, and environmentalists object strongly to it. Explain why such an objection is necessary.
19Why is mercury called an exception among metals?
20Why is ghee solid in the cold season and liquid in the hot season?
21Why is iodine mixed into common salt?
22Which chemicals are used to clean a table, glass, nail polish and the screen of a mobile phone or computer?