REVISION WORKSHEET-CLASS 8
  FORCE AND PRESSURE

ANSWER OF QUESTION 28

The woman wearing sandals with flat soles will feel more comfortable while walking on the sandy beach. The flat soles have larger area compared to the sandals with pointed heels. Since the two women are of the same weight, they will apply same force on the ground. Therefore, the pressure exerted by the pointed heels will be more compared to that with sandals having flat soles. As a result the pointed heel sandals will sink more in the sand than the flat sole sandals. Hence, walking with flat sole sandals will be more comfortable.

RREVISION WORKSHEET

8 METALS AND NONMETALS

class 8 revision worksheet
COMBUSTION AND FLAME

chemical properties of
ethanoic acid

Ethanoic Acid ( /Acetic Acid :

• 5-8% solution of acetic acid in water is called vinegar.
• Pure acetic acid is called glacial acetic acid

	REACTS WITH	PRODUCTS
1.	SODIUM Na	SODIUM ETHANOATE AND HYDROGEN
2.	SODIUM CARBONATE	SODIUM ETHANOATE, CARBON DIOXIDE AND WATER
3.	SODIUM BICARBONATE	SODIUM ETHANOATE, CARBON DIOXIDE AND WATER
4.	ETHANOL (IN PRESENCE OF CONC. SULPHURIC ACID)	ESTER AND WATER
5.	NAOH	SODIUM ETHANOATE AND WATER

esterification

Carboxylic acids react with alcohols in presence of few drops of concentrated sulphuric acid as catalyst and form sweet smelling compounds called ester.

Hydrolysis On heating with an acid or a base the ester forms back the original alcohol and carboxylic acid.

• Alkaline hydrolysis of ester is also called saponification.

• Soaps and Detergents

  • Soap is sodium and potassium salt of carboxylic acids with long chain.
  • Soaps are effective with soft water only and ineffective with hard water.
  • Detergents are ammonium or sulphonate salts of carboxylic acids with long chain. They are effective with both soft as well as hard water.
  An ionic part (hydrophilic) and a long hydrocarbon chain (hydrophobic)part constitutes the soap molecule.
  
  Long chain of carboxylic acid, hydrophobic ionic end, hydrophilic
  Structure of a Soap molecule
  Cleansing Action of Soaps
  Most dirt is oily in nature and the hydrophobic end attaches itself with dirt, while the ionic end is surrounded with molecules of water. This result in formation of a radial structure called micelles.
  
  • An emulsion is thus formed by soap molecule. The cloth needs to be mechanically agitated to remove the dirt particles from the cloth.
  • Scum : The magnesium and calcium salts present in hard water reacts with soap molecule to form insoluble products called scum, thus obstructing the cleansing action. Use of detergents overcome this problem as the detergent molecule prevents the formation of insoluble product and thus clothes get cleaned.

WORKSHEET
NUTRITION IN ANIMALS
CLASS VII

Very short answer type questions

Question 1: Where is water from undigested food absorbed in the body?
Question 2: Where is digested food absorbed in the body?
Question 3: Name the type of teeth which are for

1. Chewing and grinding food
2. Piercing and tearing food
3. Biting and cutting food

Question 4: Name the parts of Amoeba which help it in moving and capturing food.
Question 5: State whether the following statements are true or false

1. The tongue helps in mixing saliva with food.
2. Digestion of starch starts in stomach.
3. Amino acids provide energy to our body.
4. The blood takes digested food to all the cells of the body.

Short answer type questions

Question 6: What do you understand by term ‘assimilation’ in the process of digestion?
Question 7: How is food ingested by Amoeba?Explain with the help of a diagram
Question 8: What happens to food in stomach?
Question 9: Where is saliva produced? Write about its main functions.
Question 10: How is the process of digestion different in ruminants?
Question 11: What is a gall bladder? What is its role?
Question 12: What is villi ?where is it present?explain its role in digestion
Question 13: Why do we get instant energy from glucose?

Long answer type questions Question 14: Briefly describe the process of nutrition in amoeba
Question 15: Write the functions of different types of teeth.
Question 16: Briefly explain the process of digestion in ruminants
Question 17: Draw a labeled diagram of human digestive system.
Question 18: Write about the various steps involved in the process of nutrition.

Match the columns

Column 1	Column 2
1. frog	a. engulfs food by false feet
2. hydra	b. catches insects with its tongue
3. Amoeba	c. uses tentacles for ingestion of food
4. spider	d. uses cilia for ingestion of food
5. paramecium	e. uses proboscis to get food
6. butterfly	f. lives on liquid food
7. tearing of meat	g. milk teeth
8. teeth that fall off in children	h. tongue
9. taste buds	i. mastication
10. chewing and mixing of food	j. canines

Answer to match the column type question
1 – b      2 – c       3 – a       4 – f       5 – d      6 – e      7 – j        8 – g       9 – h      10 –  

class 10 experiment no 4

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lesson notes class 10 continued.....

class 10 practical no 4

revision worksheet class 9

class IX practicals
MIXTURES AND COMPOUNDS

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class 10 lesson notes of carbon and its compounds