Extra Questions from Wastewater Story

 

Q 1. What is waste water ?

Ans. 1: Water rich in lather, mixed with oil and black-brown in colour that goes down the drains from sinks, showers, toilets, laundries is dirty. Such water is called wastewater.

Q. 2. What is sewage ? What is the name given to the impurities present in it ?

Ans. 2: Sewage is wastewater released by homes, industries, hospitals, offices and other users. It also includes rainwater that has run down the street during a storm or heavy rain. Moreover, the water that washes off roads and rooftops carries harmful substances with it. Thus, sewage is a liquid waste. 

Most of it is water, which has dissolved and suspended impurities. These impurities are called contaminants.

Q. 3. Describe briefly the network of pipes etc. that acts as a transport system for sewerage.

Ans. 3: In a home or a public building usually one set of pipes brings clean water and another set of pipes takes away wastewater. 

If we could see through the ground, we would see a network of big and small pipes, called sewers, forming the sewerage. It acts as a transport system that carries sewage from the point of being produced to the point of disposal i.e., treatment plant.

Manholes are located at every 50 m to 60 m in the sewerage, at the junction of two or more sewers and also at points where there is a change in direction.

Q. 4. Write a brief note on vermi-processing toilet.

Ans. 4: A design of a toilet in which humans excreta is treated by earthworms has been tested in India. 

It is a novel, low water-use toilet for safe processing of human waste. The operation of the toilet is very simple and hygienic. The human excreta is completely converted to vermi cakes — a resource much needed for soil.

Q. 5. Fill in the blanks :(a) Cleaning of water is a process of removing _______________.
(b) Wastewater released by houses is called _______________ .
(c) Dried _______________ is used as manure.
(d) Drains get blocked by _______________and _______________.

Ans. 5.
(a) Cleaning of water is a process of removing pollutants.
(b) Wastewater released by houses is called sewage.
(c) Dried sludge is used as manure.
(d) Drains get blocked by solid food remains and sanitary towels.

Q. 6. Name a chemical used to disinfect water.

Ans. 6. Chlorine is a chemical that is used for disinfecting water.

Q. 7. Outline your role as an active citizen in relation to sanitation.

Ans. 7: As all know, waste generation is a natural part of human activity. But we can limit the type of waste and quantity of waste produced. Open drains are very common in our localities and they cause highly unhygienic and unsanitary conditions. 

As active citizens we should approach the municipality or the gram panchayat and insist that they must ensure to get these open drains covered. If the sewage of any particular house makes the neighbourhood dirty we should request them to be more considerate about other’s health.

Q. 8. Describe any three measures for controlling water pollution.

Ans. 8: Water pollution can be controlled—
1. By avoiding release of industrial wastes, household diffuse etc. into river water.
2. By covering the mouths of the wells to ensure that dust leaves etc. may not fall into it.
3. By avoiding washing clothes and bathing with soap near the sources of water.

Q. 9. Fill in the blanks :1. Raw sewage is the _______________ hazard.
2. In _______________ treatment, sewage water is treat with anaerobic bacteria.
3. The solid matter that settles to the bottom of the settling tank is called _______________.
4. The sewage is carried by draingae pipes or _______________.
5. Chlorination is done during _______________ treatment.

Ans. 9:
1. Raw sewage is the health hazard.
2. In secondary treatment, sewage water is treated with anaerobic bacteria.
3. The solid matter that settles to the bottom of the settling tank is called sludge.
4. The sewage is carried by draingae pipes or sewers.
5. Chlorination is done during tertiary treatment.

Q. 10. Describe how sewage is treated.

Ans. 10. Raw sewage is a health hazard. Sewage treatment plants are designed to treat large volume of sewer water and turn it into water that can be considered safe to drink and also put to other uses like agricultural and industrial uses.

In sewage treatment plants, the treatment consists of three stages. In the first stage (called primary treatment), the sewage is passed through coarse screens or sieves. The liquid material is then passed through settling tanks. The suspended materials settle in the tanks and form sludge.

The second stage, called secondary treatment, consists of treating the sewage water that received after first stage with anaerobic bacteria, which break down the sewage water into harmless substances. Moreover, more sludge is formed. At the end of the stage, foul smell of sewage water is not much present.

During the third stage, chlorination is done to kill disease causing organisms. This is also called tertiary treatment.

Q. 11. Fill in the blanks :

1. The suspended matter in the sewage is used to make _________________.
2. Addition of disease causing organisms in water is called water _________________.
3. _________________ bacteria is used to treat sludge.
4. _________________ in open cause health hazards.
5. Sludge and _________________ are the products of water clarification.
6. _________________ is used as manure.

Ans. 11:

1. The suspended matter in the sewage is used to make fertilisers.
2. Addition of disease causing organisms in water is called water contamination.
3. Anaerobic bacteria is used to treat sludge.
4. Defecation in open causes health hazards.
5. Sludge and biogas are the products of water clarification.
6. Activated sludge is used as manure.

Q. 12. Which of the following diseases is caused by polluted water.
(a) typhoid (b) Cholera
(c) hepatitis (d) All of these.

Ans.  12: (d) All of these

Q. 13. Choose true and false statements from the following :

1. Chemicals like chlorine and ozone are used to disinfect water.
2. We should not defecate in open as untreated human excreta is a health hazard.
3. Wastewater cannot be reused.
4. Poor sanitation and contaminated drinking water is the cause of a large number of diseases.
5. Treatment plants increase the pollutants in wastewater.

Ans. 13: 1. T, 2. T, 3. F, 4. T, 5. F.

1. Chemicals like chlorine and ozone are used to disinfect water - True
 
2. We should not defecate in open as untreated human excreta is a health hazard - True

3. Wastewater cannot be reused - False, 

Wastewater can be reused by its treatment at treatment plants.

4. Poor sanitation and contaminated drinking water is the cause of a large number of diseases - True

5. Treatment plants increase the pollutants in wastewater - False (Correct answer is - Treatment plants decrease the pollutants in wastewater).

Q. 14. In sewerage, mainholes are located at every :

(a) 50–60 m (b) 70 – 80 M
(c) 80 – 90 m (d) 90 – 100 m

Ans. 14: (a) 50 – 60 m

(In sewerage, mainholes are located at every 50-60 m).

Q. 15. Which one of the following is a quality of wastewater ?

(a) Dirty and repelling look (b) Bad taste
(c) Fowl smell (d) All the above

Ans. 15: (d) All the above

(Waste water has dirty and repelling look, is bad in taste and has fowl smell, so all the given answers are right).

Class 7 Science Answers to Acids,Bases and Salts Test Paper-1

M.M: 39 marks                       Dated: 31/05/2011

Time:  45 minutes

Q 1: Write True or False for the following plus write the correct answer for the false statements: (1 mark each x 10 = 10 marks)

       i. The word acid comes from the latin word “acere” which means bad – False (Acere means to taste sour).

     ii.  Substances which are bitter in taste and feel soapy on touching are called salts – False (Correct answer is Substances which are bitter in taste and feel soapy on touching are called bases).

   iii.  Acids turn red litmus blue – False (Correct answer is Acids turn blue litmus red).

   iv.  Neutral solutions are more acidic and less basic – False (Neutral solutions are neither acidic nor basic and thus they are called neutral).

     v. Sodium hydroxide turns red litmus to blue – True (Sodium hydroxide is a base and bases turns red litmus to blue).

   vi. The symbol for sodium is S – False (Symbol for sodium is Na).

 vii.  The symbol for potassium is K - True.

viii.  The sting of an ant contains an acid called acetic acid – False (The sting of an ant contains an acid called Formic acid).

   ix. The formula for sodium hydroxide is NaH – False (The formula for sodium hydroxide is NaOH).

     x. The formula for hydrochloric acid is HoCl – False (The formula for hydrochloric acid is HCl).

Q 2: Fill in the blanks  (1 mark each x 16 = 16 marks)

       i.  The formula of sodium chloride is NaCl.

     ii.  The formula of sulphuric acid is H2SO4.

   iii.   Acid + Base -------------> Salt + Water.

   iv.   Name of one common antacid is Milk of Magnesia, Mg (OH)2.

     v.  The formula of water is H2O.

   vi.   The formula of nitric acid is HNO3.

 vii.    In case of neutral substances, when one drop of their solution is put on either blue litmus or red litmus paper, there is no change in the colour of litmus paper.

viii. Bases turns red litmus to blue.

   ix. A base which is soluble in water is called an alkali.

     x. Sulphuric acid is used in making storage batteries for cars, buses, trucks, inverters.

   xi.  Carbonic acid is sued in fizzy soft drinks and soda water. (Formula of Carbonic acid is H2CO3)

 xii.   Lactic acid is present in curd and in sour milk. (Formula of lactic acid is C3H6O3)

xiii.  Tartaric acid is present in tamarind, unripe grapes, and unripe mangoes.

xiv.  Oxalic acid is majorly present in spinach.

  xv. Organic acids are the naturally occurring acids which are found in various types of plants and animals.

xvi.  Acids turn blue litmus to red.

Q 3: Name one natural and one synthetic indicator.                                                    (1 mark)

A 3: Some of the natural indicators are litmus (obtained from lichen and is purple in colour), red cabbage leaves, petals of petunia or geranium and turmeric solution (obtained from natural products).

Some of the synthetic Indicators – methyl orange and phenolphthalein (These are prepared and are not natural, watch out for the spelling of phenolphthalein).

Q 4: Write names of two neutral substances. 

 (1 mark)

A 4: Pure distilled water and Sodium chloride solution, NaCl (common salt) are examples of neutral substances. Some more neutral substances are (it is better to know more) sugar, calcium 
carbonate and calcium chloride etc. are neutral.

Q 5: Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.                                                    (2 marks)

A 5: The nature of the given solution can be basic or neutral.

Basic and neutral solutions do not change the colour of blue litmus paper. Since blue litmus remains blue after dipping in the solution, the solution will be either basic or neutral in nature.

To know more about the solution type, put a drop of this solution on a red litmus paper. If it turns blue, then the above solution is basic in nature and if no colour change occurs, then it is definitely a neutral solution.

Q 6: What is meant by acid rain? How is acid rain caused? What two damages are caused by acid rain?   (3 marks)

A 6: Rain containing acid in the form of mild (not very strong) sulphuric acid and nitric acid due to chemical reaction of rain water with sulphur dioxide and nitrogen oxide is called acid rain.

Human activities such as release of sulphur dioxide by power plants and release of nitrogen oxide by burning of fossil fuels (petrol, diesel and coal) and their mixing with rain water are responsible for acid rain. The sulphur dioxide n air react with water to form sulphuric acid and nitrogen oxide react with rain water to form nitric acid.

Acid rain causes following damages:

1. Aquatic plants and animals may die due to acid mixing in sea and river water.

2. Causes damage to trees at high elevations (heights).

3. Causes damage to buildings and old historical monuments.

4. The sulphur dioxide and nitrogen dioxide give rise to respiratory problems such as asthma,headaches, and irritation in eye, nose, and throat.

Q 7: Name two materials which should be added to acidic soil to reduce the acidity. Give reason.  

(3 marks)

A 7: Lime (Calcium carbonate), wood ashes and oyster shells can be added to make soil basic and reduce its acidity.

Lime is an alkali and thus neutralises the acidic effect and thus reduces the acidity. Wood ashes and oyster shells are also used to make the soil basic and reduce its acidity.

Q 8: What are three types of salts? Give one example of each type of salt.                    (3 marks)

A 8: A salt is a product formed by the neutralization of an acid by a base.

Three types of salt are:

1. Acidic
2. Basic
3. Neutral

Example of acidic salt is NH4Cl (Ammonium chloride).

Example of basic salt is Na2CO3 (Sodium carbonate).

Example of neutral salt is NaCl (Sodium chloride).

Answers of Science Class VIIth Chapter 2 Nutrition In Animals

(a) The main steps of nutrition in humans are __________, __________, ___________, __________ and __________

(b) The largest gland in the human body is __________.

(c) The stomach releases hydrochloric acid and ________ juices which act on food.

(d) The inner wall of the small intestine has many finger-like outgrowths called __________.

(e) Amoeba digests its food in the __________.

Answer 1:  (a) The main steps of nutrition in humans are ingestion, digestion, absorption, assimilation and egestion.

(b) The largest gland in the human body is liver.

(c) The stomach releases hydrochloric acid and digestive  juices which act on food.

(d) The inner wall of the small intestine has many finger-like outgrowths called villi.

(e) Amoeba digests its food in the food vacuole.

Question 2: Mark ‘T’ if the statement is true and ‘F’ if it is false:

(a) Digestion of starch starts in the stomach. (T/F)

(b) The tongue helps in mixing food with saliva. (T/F)

(c) The gall bladder temporarily stores bile. (T/F)

(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T/F)

Answer 2: (a) Digestion of starch starts in the stomach. (F)

(b) The tongue helps in mixing food with saliva. (T)

(c) The gall bladder temporarily stores bile. (T)

(d) The ruminants bring back swallowed grass into their mouth and chew it for some time. (T)

Question 3: Tick ( √) mark the correct answer in each of the following:

(a) Fat is completely digested in the

(i) stomach

(ii) mouth

(iii) small intestine

(iv) large intestine

(b) Water from the undigested food is absorbed mainly in the

(i) stomach

(ii) food pipe

(iii) small intestine

(iv) large intestine

Answer 3 (a) Fat is completely digested in the

(i) stomach

(ii) mouth

(iii) small intestine √

(iv) large intestine

Answer 3 (b) Water from the undigested food is absorbed mainly in the

(i) stomach

(ii) food pipe

(iii) small intestine

(iv) large intestine √

Question 4: Match the items of Column I with those given in Column II:

Column I	Column II
Food components	Product(s) of digestion
Carbohydrates	Fatty acids and glycerol
Proteins	Sugar
Fats	Amino acids

Answer 4:
Food components	Product(s) of digestion
Carbohydrates	Sugar
Proteins	Amino acids
Fats	Fatty acids and glycerol

Question 5: What are villi? What is their location and function?

Answer 5: Villi are tiny finger-like projections originating from the walls of the small intestine. They increase the surface area for absorption of the digested food. The blood vessels present inside the villi can absorb the nutrients from the digested food.

Structure of a villus

 Question 6: Where is the bile produced? Which component of the food does it help to digest?

Answer 6: Liver secretes the bile juice which is stored in the gall bladder. Bile plays an important role in the digestion of fats.

Question 7: Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Answer 7: Cellulose is a type of carbohydrate that can be digested by ruminants and not by humans. Ruminants have a large sac-like structure between small and large intestine where the food containing cellulose is digested by the action of certain bacteria. On the other hand, humans cannot digest cellulose, as the cellulose digesting enzymes are absent in them.

Question 8: Why do we get instant energy from glucose?

Answer 8: Glucose is a simple sugar. Carbohydrates, when consumed, have to be digested into glucose. As glucose can be easily absorbed in blood, it provides energy to the body. Hence, when glucose is directly taken, it does not have to be digested and thus acts as an instant source of energy.

Question 9: Which part of the digestive canal is involved in:

(i) absorption of food ____.

(ii) chewing of food ____.

(iii) killing of bacteria ____.

(iv) complete digestion of food ____.

(v) formation of faeces ____.

Answer 9: (i) absorption of food small intestine.

(ii) chewing of food buccal cavity.

(iii) killing of bacteria stomach.

(iv) complete digestion of food small intestine.

(v) formation of faeces large intestine.

Question 10: Write one similarity and one difference between the nutrition in Amoeba and human beings.

Answer 10: Similarity between nutrition in Amoeba and human beings:

Both Amoeba and humans require energy for the growth and maintenance of their bodies. This energy is derived from the food that they eat. The food that they consume is always in a complex form and is therefore broken down into simpler forms by the process of digestion. Hence, both these organisms are heterotrophs.

Differences between nutrition in Amoeba and human beings:

	Digestion in Humans		Digestion in Amoeba
(i)	Humans have a mouth and a complex digestive system.	(i)	Mouth and digestive system are absent in Amoeba.
(ii)	Digestive juices are secreted in the buccal cavity, stomach, and small intestine.	(ii)	Digestive juices are secreted in the food vacuole.
(iii)	Digestion of carbohydrates, proteins, and fats starts in separate regions.	(iii)	All the food components are digested in the food vacuole.

Question 11: Match the items of Column I with suitable items in Column II

-		Column I		-	Column II
(a)		Salivary gland		(i)	Bile juice secretion
(b)		Stomach		(ii)	Storage of undigested food
(c)		Liver		(iii)	Saliva secretion
(d)		Rectum		(iv)	Acid release
(e)		Small intestine		(v)	Digestion is completed
(f)		Large intestine		(vi)	Absorption of water
-		-		(vii)	Release of faeces
Answer		11:

-	Column I	-	Column II
(a)	Salivary gland	(iii)	Saliva secretion
(b)	Stomach	(iv)	Acid release
(c)	Liver	(i)	Bile juice secretion
(d)	Rectum	(ii)	Storage of undigested food
(e)	Small intestine	(v)	Digestion is completed
(f)	Large intestine	(vi)	Absorption of water

Question 12: Label the following figure of the digestive system.

A part of human digestive system

Answer 12: