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Samcheer Kalvi 6th Science Books English Medium Chemistry in Everyday life

Science : Term 3 Unit 3 : Chemistry in Everyday life

I. Choose the correct answer:

1. Soaps were originally made from ___________.

  1. proteins
  2. animal fats and vegetable oils
  3. chemicals extracted from the soil
  4. foam booster

Ans : animal fats and vegetable oils

2. The saponifi cation of a fat or oil is done using _______________ solution for hot process

  1. potassium hydroxide
  2. sodium hydroxide
  3. Hydrochloric acid
  4. sodium chloride

Ans :  sodium hydroxide

3. Gypsum is added to the cement for ______________________.

  1. fast setting
  2. delayed setting
  3. hardening
  4. making paste

Ans : delayed setting

4. Phenol is ________

  1. carbolic acid
  2. acetic acid
  3. benzoic acid
  4. hydrochloric acid

Ans : carbolic acid

5. Natural adhesives are made from ___________.

  1. protein
  2. fat
  3. starch
  4. vitamins

Ans : starch

II. Fill in the Blanks 

1. ____________ gas causes tears in our eyes while cutting onions.

Ans : propanethial s-oxide

2. Water, coconut oil and __________ are necessary for soap preparation.

Ans : sodium hydroxide

3.  ______ is called as farmer’s best friend.

Ans : earthworm

4. __________ fertilizer is ecofriendly

Ans : organic

5. _____________ is an example for natural adhesive.

Ans : starch

III. True or False. If False, give the correct statement

1. Concentrated phenol is used as a disinfectant.

Ans : True

2. Gypsum is largely used in medical industries.

Ans : False

Cu. An. : Epsom is largely used in medical industries

3. Plaster of Paris is obtained from heating gypsum.

Ans : True

4. Adhesives are the substances used to separate the components.

Ans : False

Cu. An. : Adhesives are the substances used to paste the components.

5. NPK are the primary nutrients for plants.

Ans : True

IV. Match the Following

1. SoapC6H5 OH
2. CementCaSO4.2H2O
3. FertilizersNaOH
4. GypsumRCC
5. PhenolNPK

Ans : 1 – C, 2 – D, 3 – E, 4 – B, 5 – A

V. Arrange the following statements in correct sequence

1. Pour that solution into an empty match box, soap can be obtained after drying.

2. Take necessary quantity of water in a jar

3. Then add coconut oil drop by drop and stir it well.

4. Add concentrated sodium hydroxide in the jar and allow it to cool.

5. Try this soap to wash your hand kerchief

6. Cover your work area with old newspaper.

Ans :

6. Cover your work area with old newspaper.

2. Take necessary quantity of water in a jar

4. Add concentrated sodium hydroxide in the jar and allow it to cool.

3. Then add coconut oil drop by drop and stir it well.

1. Pour that solution into an empty match box, soap can be obtained after drying.

5. Try this soap to wash your hand kerchief

VI. Analogy

1. Population Urea : Inorganic fertilizer: Vermi compost: ____________.

Ans : organic fertilizer

2. _____________: Natural adhesives: Cello tape: Artificial adhesives.

Ans : starch

VII. Give very short answer 

1. What are the three main constituents of soap?

Soaps are prepared by heating the mixture of olive oil, animal fat and concentrated sodium hydroxide solutions.

2. What are the two different types of molecules found in the soap?

The detergent molecules have two sides, one side water loving, other water hating. Water hating goes and joins with dirt and oil in the cloth while the water loving joins with the water molecules.

3. Give an example for inorganic fertilizer

  • Urea
  • Ammonium sulphate
  • Super phosphate

4. Mention any three physical properties of phenol.

  • It is a volatile.
  • white crystalline powder.
  • It is a colorless solution, but changes into red in the presence of dust

5. Explain the uses of plaster of paris

  • In making black board chalks.
  • In surgery for setting fractured bones.
  • For making casts for statues and toys etc.
  • In construction industry.

6. What are the ingredients of the cement?

The cement is manufactured by crushing of naturally occurring minerals such as lime, clay and gypsum through milling process.

7. Why gypsum is used in cement production?

Cement becomes hardened when it is Cement mixed with water. Gypsum plays a very important role in controlling the rate of hardening of the cement

VIII. Give short answer

1. Why earthworm is called as farmer’s friend?

Earthworms take organic wastes as food and produce compost castings. So earthworms are known as Farmers’ friends.

2. Explain the process of manufacturing cement.

The cement is manufactured by crushing of naturally occurring minerals such as lime, clay and gypsum through milling process.

3. What are uses of Gypsum?

  • Used as fertilizers.
  • Used in the process of making cement.
  • In the process of making Plaster of Paris.

IX. Answer in detail

1. What is potable water? List down its characteristics.

Materials Required:

35 ml of water 10 g. of Lye (Sodium hydroxide) 60 ml of coconut oil.

Process:

Cover your work area with old newspaper. Take 35 ml of water in a jar. Add 10 gram of concentrated sodium hydroxide and allow it to cool.

Then add 60 ml of coconut oil drop by drop and stir it well. Pour that solution into an empty match box, soap can be obtained after getting dried.

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