Recent

A Day at Nehru Science Centre - Worli

Educational visit to Science Centre by Enfantian

Toypedia

Avtivity area made for Kindergarten

Educational Camp

Visit to Yusuf Meherally Centre - Karnala. Students attended workshops of Vermi-culture, Biogas Plant, Soap Making, Oil Extraction, Carpentry, Pottery etc

Enfant India Fest - WAVES

WAVES Present - EVS, Mathematics Innovations, Science Fest, Enfanthusia, Food Carninal, Fun n Fair, Annual Day, Farewell and Various Competitions.

Information Technology ( Computer Lab )

Well Equipped Computer and Science Lab

Friday, January 29, 2021

Std 5 Class Test English

Q.1) Make meaningful sentences using the following words.                                     (2) 
(1) Notice -----------------------------------------------------------
(2) Get a hold of ---------------------------------------------------
(3) Add proper prefixes like up ,un, dis, in , to the following  To form opposites.    (2) 
(1) Happy -----------------
(2) Believe -----------------
   (3) Give the antonyms of .                 (2) 
       (1) Correct ----------------- 
       (2) Slow -------------------

   (4) Name and list some countable and uncountable
Things around you ?                             (2)
Ans)-------------------------------------------------------------------
(5)Which animals stay in the zoo ?    (2)
Ans)----------------------------------------------------------------------

Std 4 Class Test English

Q.1 Give opposite for:                            (02)
 a) heaven ×
 b) brilliant × 
 c) catch × 
 d) desire ×
 
 Q.2 Give meaning for the following:    (03)
 1) brittle :.        
 2) impermeable :
 3) recyclable :

Q.3 Answer the following questions . (05)
1) what is stained glass?
2) Who is happier young children or grown-up ?
3) what can we do to build our confidence?
4) what did she dream while sleeping?
5) How glass can be recycled?

Std 3 Class Test Marathi


प्र.१): खालील प्रश्नांचे उत्तर लिहा.                   (०४)
    १) तळे कशामुळे साचले?
     २) धरण कशामुळे भरले?
     ३) धरणाचे पाणी कोठे जाते?
     ४) वाऱ्यावर काय डुलते?
     
प्र.२): चित्र पाहा आणि नाव लिहा.                 ( ०४)
     १) 🐴
     २) 🐘
     ३) 🐟
     ४) ☀️
प्र.३): अर्थ लिहा . (In English)                    (०२)
१.  नाक  -  _____________
२.  वर्षा  -  _____________

Std 2 Class Test Hindi

Std 1 Class Test Hindi

१)जोडियाँ लगाओ .                                5marks 

 👣                           बादल 

✍                             बोटल  
  
⛅                            घङी 

⏰                            हाथ 

🍼                            पैर 

२)दो अक्षर वाले शब्द लिखो .(कोई तीन)     3marks 

 १)____________

 २)_____________

 ३)_____________


३)विलोम शब्द लिखो  .                             2marks 

 १. अन्दर ×__________

 २. दूर ×____________

Class 6 sub: Science Weekly Test

Std VI           Subject – Science
Marks- 10

Q1)  Fill in the blank 3M                                 
a) Rubber made by vulcanization is a________ material
b) Man-made materials are made by _________natural material
c) Rayon is also known as_______

 Q2) What are we Used for            2M                      a) Wood b)paper

Q3) find out            1M 
    a) How are pearls obtained


Q4)  Give scientific reason  2M
     
a) Man-made materials have more demand
Q5) Answer the fallowing question 
a) What is vulcanization ? 2M

Class 7 Sub: Science Weekly Test

Std VII           Subject – Science
Marks- 10

Q1)  Fill in the blank 3M                                 
a) Garbage is converted into______ by organism
b) An electron-microscope is necessary for the study of_______
c) The organelles called the_______ is presentr in plant cell only

 Q2) What are the different between us?   2M                      a) prokaryotic cell and eukaryotic cell 

Q3)  Explain the uses and the harmfull effect of micro-organism                                            1M 
    
Q4)  Give scientific reason     2M
     
a) Bread rises during baking
Q5) Answer the fallowing question    2M
a) Sketch and describe in your own words of animal cell

Class 8 Sub: Science Weekly Test

Std VIII                Subject – Science
Marks- 10

Q1) Give Function 3M                                 
a) Lysosome b) Cytoplasam c) nucleus

 Q2) Wooden doors fit tightly in rainy season . why does it happen ?            2M

Q3) Explain the  structure of the nucleus with a labelled diagram            3M 


Q4)  Explain Mitocondria and its function?   2m

Std-12 Science Sub-Physics Weekly test

Burlington junior college 
Sub-Physics.  Class-12 Science 
Marks-10

Note: Attempt all question from the following.

Q.1 Attempt any six  from the following
1. What is photo cell?
2 what is photoelectric effect?
3. What is Faraday first law of electromagnetic induction?
4.What is phasors?
5. What is LC oscillation?
6. What is De Brogli e hypothesis?
7. What is cyclotron motion?

Q.2 Attempt any two from the following
1. Explain Devisson and Germer experiment.
2. Explain diamagnetism?
3. Distinguish between AC and DC current.

Std-12 Commerce Sub-OC&M Weekly test

Burlington junior college 
Class:12 Commerce 
Sub: O.C
Marks: 10

Q.1 write Rights of Consumers.          6m

Q.2 Distinguish between State commission and national commission.     4m

Std-12 Arts Sub-political science weekly test

Burlington junior College
Class 12 Art's
Subject -political science
Marks -10

Q1-  Answer the Following
a) what is the left wing extremism in India.
b) explain cross border terrorism in Jammu and Kashmir.


سوال نمبر 1۔ مندرجہ ذیل
 سوالوں کے مفصل جوابات لکھیے۔الف) بھارت میں بائیں بازو کی انتہا پسندی کیا ہے؟
ب) جموں و کشمیر میں سرحد پار سے کی جانے والی دہشت گردی کی وضاحت کیجئے  ۔

Std-10 Sub-science Weekly class test

Enfant India English School 
Subject: Science 
Topic: Metallurgy 
Std: 10th 

Q1) Explain Froth floatation process 
Q2)  Define Metallurgy
Q3)  Give scientific reason Pine oil is used in froth flotation.
Q4) Draw a neat labelled diagram Hydraulic separation method.
Q5) Define roasting & Calcination?

Std-9 Sub-English Weekly Test

Enfant India English School 
Class-9th 
Sub-English 
Marks-10


A)  Find from the lesson, the antonyms of the following.(3M) 

Afterwards 
Spending 
Careful 
Withdraw 
Confidently 
Cheerful 

B) Fill in the blanks choosing an appropriate word from the lesson. (3M) 
a) In the examination, I did not know the answer,  so I-----------------------------
b)In the examination, I did not know the answer,  so i-------------------------------
c) He was dizzy and he-------------------------------------Into the room. 
d) The sight of a snake--------------------------------------------------
e) While arguing with his elders he had----------------------------------------
f) As soon as I-------------------------------------of my home,  I greet my family.

C)Letter Writing:(4M) 
Write a letter to your friend wishing him a Happy birthday.
And mention why you are unable to go on his/her birthday party.

Wednesday, January 27, 2021

Class 8 Science 7 – Metals and Non-Metals Questionnaire with Answer

 

7 – Metals and Non-Metals

 

Q 1.Identify the odd term:

Ans

(1) Diamond. (Others are metals.)

(2) Brittleness. (Other properties metallic properties.)

(3) Bromine. (Others are solids.)

 (4) Iron. (Others are alloys.)

 

Q. 2 Give scientific reasons :

(1) The stainless steel vessels in kitchen have copper coating on the bottom.

Ans. (1) Stainless steel is an alloy of iron with carbon, chromium and nickel.

(2) The conductivity of copper is higher than that of iron in steel. Copper heats uniformly and faster. The time for cooking is reduced, as a result it saves fuel. Hence, we stainless steel vessels in kitchen have copper coating on the bottom.

(2) Copper and brass vessels are cleaned with lemon.

Ans  Copper underegoas oxidation in air to form black copper oxide. Copper oxide reacts slowly with carbon diaoxide in air and gains a green caot. This green substance is copper carbonate. (2) Lemon contains acid. The acid dissolves the green coating of basic copper carbonate present on the surface of a tarnished copper and brass vessels and makes them shiny again.

(3) Sodium metal is kept in kerosene.

Ans. (1) Sodium reacts so vigorously with atmospheric oxygen and water that it catches fire if kept in the open. (2) It does not react with kerosene and sinks in it. Hence, to protect sodium and to prevent accidental fires it is always kept in kerosene

 

Q 3. Answer the following.

(1) What are the uses of noble metals?

Ans. Uses of Noble Metals:

(1) Gold, silver and platinum are used to prepare ornaments.

(2) Silver is used in medicines. (It has antibacterial property),

(3) Gold and silver are also used to make metals and few electronic devices.

(4) Platinum, palladium metals are used as catalyst.

 

(2) What is done to prevent corrosion of metals?

Ans. By applying a layer of paint, oil, grease or varnish on the surface of a metal to prevent corrosion. Also plating 'Will non corroding metal is done. Iron is coated with thin layer of zinc. Due to these processes the contact of metal surface with air is lost and corrosion is prevented.

(3) What are the adverse effects of corrosion?

Ans. (1) A reddish coloured deposit (rust) is formed on iron by reaction with oxygen gas.

(2) A greenish carbonate) is for (copper carbonate) is formed on copper by reaction

with carbon dioxide.

(3) A blackish coloured deposit is formed (silver sulphide) on silver.

 (4) Corrosion causes damages to car bodies, bridges, iron railings, ships specially of iron, silver articles and copper vessels.

 

(4) What are the metals that make the alloys brass and bronze?

Ans. The alloy brass is formed from copper and zinc and the alloy bronze is formed from copper and tin.

.

Q. 4 Complete the table : (Answers are given directly.)

       Property of metal                   Use in everyday life

(1) Ductility                                  (1) Gold, silver ornaments

(2) Malleability                             (2) Aluminium sheets, galvanised sheets

(3) Conduction  of heat                (3) Stainless steel vessels, copper vessels, boilers

(4) Conduction of electricity         (4) Copper wires

(5) Sonority                                  (5) Brass articles

 

Q.5. Activity-based question :

• Activity - Three experiments to study the process of rusting are given below. Observe the three test tubes and answer the following question

 (1) Why the nail in the test tube 2 is not rusted?

Ans. In the test tube 2, oil cuts the supply of air to nail due to which oxidation of nail is prevented and boiled water is free from gases. Hence, the nail in the test tube 2 is not rusted.

(2) Why is the nail in the test tube 1 is rusted highly?

Ans. The nail in the test tube 1 is highly rusted because nail is in contact with water and air. The oxidation process is fast.

(3) Would the nail in the test tube 3 get rusted?

Ans. No change is observed in the test tube 3. Nail remains as it is because the calcium chloride absorbs moisture, making the air dry, thus preventing rusting of the nail.

 

Class 7 Science 7- Motion, Force and Work Questionnaire with Answer

                                7- Motion, Force and Work

 

1.    Fill in the blanks with the proper words from the brackets :

Ans (1) constant  (2) zero (3) speed  (4)velocity

 

Q 2. Explain the following concepts in your own words with everyday examples:

    force work, displacement, velocity, acceleration, distance.

Ans. We perform many activities in our daily life by suing force. e.g. lifting the luggage. pushing a vehicle, riding a bicycle, taking things from lower floor to upper ones. The work done by force (F), W = F x s. Here s is the displacement taking place in the direction of the force.

       When a hand cart is pushed with a certain force some work is done. Lifting our school bag and carrying it to school is also a work. We cover some distance as we go to school from home the displacement takes place. We keep on changing velocity during this travel. When we travel by vehicle, the distance is crossed with a certain velocity. But this velocity is not constant. If the velocity is increased, the acceleration becomes positive whereas when the brake is applied on the vehicle, the acceleration becomes negative.

 

Q. 3. A ball is rolling from A to D on a flat and smooth surface. Its speed is 2cm/s. On reaching B, it was pushed continuously up to C. On reaching D from C, its speed had become 4cm/s. It took 2 seconds for it to go from B to C. What is the acceleration of the ball as it goes from B to C?

Ans. The ball moves as follows:

The ball is rolling on a flat and smooth surface. Therefore, it will not face the frictional resistance.

The speed of ball from A to B is 2 cm/sec.

At B the speed of ball is 2 cm/second.

From C to D there is force acting on a ball. Therefore, the speed of the ball is 4 cm/sec (the speed of the ball at D)

The speed of the ball is same at all the points as it is linear motion.Therefore, the magnitude of velocity of ball = speed of the ball.

Therefore, increase in the speed from B to C = 4 cm/sec – 2 cm/sec = 2 cm/sec

Acceleration in the displacement = change in the velocity/ time = 2 cm/s/2 sec = 1 cm/s2

Thus the acceleration between Bto C = 1cm/s2

 

Q 4. Observe the figure and answer the questions:

 Ans. The distance covered by Sachin and Sameer :

A → B (3km), B → C (4 km), C → D (5km), D → E (3 km)

Total distance : 3 + 4 + 5 + 3 = 15 km

The actual distance covered = 15 km.

Total displacement: From A to E = 3 + 3 + 3 = 9 km

Total displacement = 9 km

Speed = Distance/ Time =15 km/1 hour =15 km/hour

Velocity = Displacement /Time = 9km/1 hour = 9 km/hour

The velocity from A to E is 15 km/hour which can be called the average velocity

Q. 5. From the groups B and C, choose the proper words, for each of the words in group A:

Ans

Work                           Joule                          Erg

Force                         Newton                      dyne

Displacement             Metre                         cm

 

Q. 6. A bird sitting on a wire, flies, circles around and comes back to its perch. Explain the total distance it traversed during its flight and its eventual displacement.

Ans. The bird takes a circular turn and comes back. The distance traversed by the bird is equal to the circular path that it has taken. Since bird comes back to its original position the displacement will be zero.

(Note: The path of a bird need not be in one plant. It usually flies in all the three planes. While deciding the displacement, we take into account.)

 

Q 7. Solve the following problems :

(1) A force of 1000N was applied to stop a car that was moving with a constant velocity. The car stopped after moving through 10m. How much is the work done?

Solution : Here the direction of force and displacement are opposite to each other.

That means

F = 1000 N and

s = - 10 m

.   W = F x s

    = 1000 NX (-10 m)

    = - 10000 J

 Ans. The work done W = -10000J

(2) A cart with mass 20 kg went 50m in a straight line on a plain and smooth road when a force of 2N was applied to it. How much work was done by the force?

Solution : Force (F) = 2 N

 Displacement (s) = 50 metre

      W = F x s

 (work done by force)

     W = 2 N X 50 m

      = 100J

Ans. The work done by the force W = -100J


Class 6 Science 7 - Nutrition and Diet Questionnaire with Answer

 

7 - Nutrition and Diet

 

Q 1. Fill in the blanks

Ans. 1) The process of intake of food and utilizing it for all life processes is called nutrition.

2) All the substances in our food which are useful for various bodily processes are

called nutrients.

3) Carbohydrates and fats provide energy to our body

4) In a balanced diet, all the nutrients are present in the adequate proportion

5) In the food pyramid cereals are given the maximum space because they fulfil our

Energy /carbohydrate dietary requirements

6) Intake of more food than necessary causes obesity.

 

Q 2. Choose the correct alternative

Ans. 1) Pulses are a good source of proteins.

2)Cereals provide maximum energy to the body

3)Goiter is caused by a deficiency of the mineral iodine.

4)Chocolate is a type of junk food.

5) Vitamin K is essential for blood clotting.

 

Q 3. Spot the following in the table of vitamins and minerals

1) The nutrient present in citrus fruits.  

Ans. Vitamin C

2) Vitamins / Minerals present in milk  

Ans Minerals like calcium and phosphorus and Vitamins A, B, D

3) Causes and symptoms of night blindness, scurvy rickets beriberi.  

Ans • Night blindness – Cause: Deficiency of Vitamin A Symptom: Inability to see in dim light.

• Scurvy – Cause: Deficiency of Vitamin C Symptom: Bleeding gums

• Rickets - Cause : Deficiency of Vitamin D: Symptoms : Softening of bones, causing

pain and fractures

 • Beriberi - Cause: Deficiency of Vitamin B1: Symptoms Nerve disorder

4)Foods required to prevent the above diseases.

Ans.  Food stuffs to prevent night blindness : Red and yellow vegetables and fruits. Leafy vegetables, milk, butter

• Food stuffs to prevent scurvy : Citrus fruits, lemon, amla tomato green leafy vegetables.

green vegetables

• Food stuffs to prevent rickets : Sun bathing, milk, butter, fish meal.eggs

• Food stuffs to prevent beriberi: Cereals, nuts, pulses, milk, meal fish

5) Causes of anaemia

Ans. Deficiency of iron and Vitamin B12

(1)  Essential minerals for healthy bones and teeth.

Ans. Calcium and Phosphorus:

(2)  Sensory organ affected due to the deficiency of Vitamin A.

Ans. Eyes.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Std 5 Class Test EVS 2

Q.1) Answer the following questions in brief.
(1)What are the three main steps in the process of domesticating
A wild animal? 
Ans)-------------------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------
(2) How did some people in the community become skilled
Craftsmen? 
Ans)-------------------------------------------------------------------------------------------------------------------------------
(3) Which animal is used by the modern police ? In what way? 
Ans)------------------------------------------------------------------------------------------------ -------------------------------
(4) Compare the New stone Age village with a modern village? 
Ans)------------------------------------------------------------------------------------------------- ------------------------------

(5) Big animals like mammoths were on the way to extinction? 
Ans)------------------------------------------------------------------------------------------- ------------------------------------
----------------------------------

Std 4 Class Test EVS 2

Q.1. Fill in the blanks:.                             (05)
1) The Mavlas of  the________ Mavals gathered around shivaji Maharaj.
2) ____________conferred the title of Raja on Yeshwantrao.
3) Afzalkhan was previously the subhedar __________
4) Because of ___________ Shiva was saved.
5) Shivaji Maharaj stepped in to the shamiana only when___________ moved away.

Q.2. Answer in one sentence:                (02)
1) What chalenga did Afzalkhan accept?
2) What message did Afzalkhan send shivaji Maharaj in a spirit of apparent friendliness?

Q.3. Form a correct word from the given letters.                                                    (03)
1) r  t  P  a  p  a  g  d  a  ____________________
2) j  a  i  i  S v h _________________
3) n  h  l  z  A  a  f  k  a ____________________

Std 3 Class Test Hindi


प्र.१:निम्नलिखित प्रश्नों के उत्तर लिखो:           ०५
१) सप्ताह में कितने दिन होते हैं?
२) मंगलवार के बाद कौन -सा दिन आता है?
३) सोमवार से पहले कौन सा दिन आता है ?
४) शनिवार किस दिन के पहले आता है?
५) आज बुधवार है परसों कौन -सा दिन होगा?
प्र.२: चित्र देखकर उनके नाम लिखो:               ०५
१) 🌈 _____________
२) 🐘 _____________
३) 🥎 _____________
४) 🌂 _____________
५) 🍍 _____________

Std 2 Class Test Mathematics

Std 1 Class Test Mathematics

Q.1)Fill in the blanks.                     4 Marks
 
1)   29+25=  ______

2) Write the next three numbers 8,3,8,3 __ __.

3) The successive after number 95 _____

4) The Successive number before 26 _______

Q.2) Maths the following.                4Marks 

1)10+15                      Ten

2)30+35                      Thirty

3)10+20                      Sixtyfive

4)10                            Twentyfive

Q.3) Write the Multiplication.          2Marks 

1)   2×2 = ______
2)   3×8 = ______

Monday, January 25, 2021

Class 8 Science 6 – Composition of Matter Questionnaire with Answer

                                 6 – Composition of Matter

 

Q 1. Fill in the blanks.

Ans. (1) The intermolecular force is maximum in the particles of solid.

(2) Solids retain their volume even when external pressure is applied. This property is called elasticity.

(3) Matter is classified into the types mixture, compound and element, by applying the criterion chemical composition of matter.

(4) Matter that contain two or more constituent substances is called mixture.

(5) Milk is an example of type of matter called heterogeneous mixture.

(6) Water, mercury and bromine are similar to each other, because the three are     liquids.

(7) Valency of carbon is 4 and that of oxygen is 2. From this, we understand that there are 2 chemical bond/bonds between the carbon atom and one oxygen atom in the compound-carbon dioxide.

Q. 2 Identify the odd term.

 Ans. (1) Brass. (Others are elements.)

(2) Hydrogen. (Others are compounds.)

(3) Carbon. (Others are mixtures.)

(4) Petrol. (Others are inorganic compounds.)

(5) Sugar. (Others are inorganic compounds.)

(6) Carbon. (Others are monovalent elements.)

 

Q 3. Sea water tastes salty due to the dissolved salt. The salinity (the proportion of salts in water) of some water bodies Lonar lake - 7.9%, Pacific Ocean 3.5%, Mediterrnean sea - 3.8%, Dead sea - 33.7%. Explain two characteristics of mixtures from the above information.

Ans. (1) The constituents of a mixture (the proportion of salts in water) do not combine chemically. (2) Their constituents are present in any proportion by weight. (3) The constituent of a mixture can be separated by a physical process.

following table. Identify

Q 4. Plants synthesize glucose in sunlight with the help of chlorophyll from carbon dioxide and water and give away oxygen. Identify the four compounds in this process and name their types.

Ans. Photosynthesis :

  6CO2  + 6H2O       light            C6H1206   +   602

 Carbon  Water  Chlorophyll      Glucose   Oxygen dioxide

Carbon dioxide, water, glucose, and Chlorophyll are compounds.

Types : Organic compounds : Glucose

Inorganic compounds : Carbon dioxide and water

Complex compounds : Chlorophyll.

Q 5. In one sample of brass, the following ingredients were found : copper (70%) and zinc (30%). Identify the solvent, solute and solution from these.

Ans. Brass is an alloy, it contains 70% copper and 30% zinc. The largest proportion is solvent, i.e. copper. The smaller proportion is solute, i.e. zinc. The solution is Brass.

Q 6. Give two examples each:

(1)  Liquid element.

Ans. Mercury (Hg), Bromine (Br.)

(2)  Gaseous element.

Ans. Hydrogen (H), Oxygen (O2).

(3)  Solid element

Ans. Iron (Fe), Copper (Cu), Silver (Ag).

(4) Homogeneous mixture.

Ans. Sea water, blue vitriol dissolved in water.

(5)Colloid.

Ans. Milk, blood.

(6)Organic compound.

Ans. Glucose, urea.

(7) Complex compound.

Ans. Chlorophyll, Haemoglobin.

(8) Inorganic compound.

Ans. Soda, rust, limestone.

(9) Metalloid.

Ans. Silicon, arsenic.

 (10) Element with valency 1.

Ans. Sodium (Na), potassium (K), chlorine (CI).

(11) Element with valency 2.

 Ans. Magnesium (Mg), Calcium (Ca). Q 7. Write the names and symbols of the constituent elements and identify their valencies from their molecular formulae given below: KCI, HBr, MgBr2, K2O, NaH, CaCl2, CCI4, HI, H2S, Na2S, Fes, BaCl2

Sr No                                                                  

Molecular formula

Constituent element/ Name symbol

Valency

1.

KCI

Potassium K

Chlorine C1

1

1

2.

HBr

Hydrogen H

Bromine Br

1

1

3.

MgBr2

Magnesium   Mg

Bromine Br

2

1

4.

K2O

Potassium K

Oxygen O

1

2

5.

NaH

Sodium Na

Hydrogen H

1

1

6.

CaCl2

Calcium Ca

Chlorine CI

2

1

7.

CCI4

Carbon C

Chlorine CI

4

1

8.

HI

Hydrogen H

Iodine    I

1

1

9.

H2S

Hydrogen H

Sulphur S

1

2

10.

Na2S

Sodium Na

Sulphur S

1

2

11.

FeS

Iron Fe

Sulphur S

2

2

12.

BaCI2

Barium Ba

Chlorine CI

2

1

 

Q  8 Give scientific reasons :

(1) Hydrogen is combustible, oxygen helps combustion, but water helps to extinguish fire.

Ans. (1) Water is a compound of hydrogen and oxygen. (2) In a compound, the constituents do not retain their individual properties. Hence, hydrogen is combustible and oxygen helps combustion, but water is neither combustible nor supports combustion, it helps to extinguish fire.

 

(2) The constituent substances of a colloid cannot be separated by oridinary filtration.

Ans. (1) A colloidal solution is heterogeneous. (2) The diameters of colloidal particles are of the order of 10-5 m. (3) The particles of a colloid can easily pass through a filter paper as the pore size of a filter paper is big. Hence, the constituents of a colloidal cannot be separated by filtration.

(3) Lemon sherbat has sweet, sour and salty taste and it can be poured in a glass.

Ans. (1) Lemon sherbat is a mixture. It is made up of lemon juice, sugar, salt and water. (2) Formation of lemon sherbat does not involve any chemical reaction. (3) The constituents of sherbat retain their individual properties. Hence, lemon sherbat is sweet, sour and salty to taste and it can be poured in a glass.

(4) A solid matter has the properties of definite shape and volume.

Ans. (1) The forces among the constituent particles (atom/molecules) are called intermolecular forces. (2) In solids these forces are strong enough to keep the particles together in fixed positions, as a result solids have a definite shape and volume.

 

Q 9. Deduce the molecular formulae of the compound obtained from the following pairs of elements by the cross multiplication method.

(1) C (Valency 4) and Cl (Valency 1)

Ans. Step 1: Write the symbols of the constituent elements.

                       C                Cl

Step 2: Write the valency below the respective elements.

                      C                 CI

                      4                   1

Step 3: Cross multiply the valencies.


                      C                 C

                      4                   1

     The molecular formula : CCI4

(2) N (Valency 3) and H (Valency 1)

Ans. Step 1: Write the symbols of the constituent elements.

                        Ν            Η

Step 2: Write the valency below the respective elements.

                        Ν            Η

                           3             1

 1 Step 3: Cross multiply the valencies.


                       Ν                Η

                         3                 1

 The molecular formula : NH3

(3) C (Valency 4) and 0 (Valency 2)

Ans Step 1: Write the symbols of the constituent elements.

                       C               O

Step 2: Write the valency belo respective elements.

                       C               O

                       4                2

Step 3: Cross multiply the valencies.

 


                     C                 O

                     4                  2

 

 

The formula : C2O4

The number of constituent atoms in the final molecular formula should be the smallest possible whole number. Divide the formula C2O4 by suitable number.

Final molecular formula obtained by dividing by 2.

Molecular formula : CO2

(4) Ca (Valency 2) and O (Valency 2)

Ans. Step 1: Write the symbols of the constituent elements.

                     Ca                  O

Step 2: Write the valency below the respective elements.

                    Ca                 O

                     2                   2

Step 3: Cross multiply the valencies.

                   Ca                 O

                     2                   2

The formula : Ca2O2

Divide the formula by suitable number *2. The molecular formula : CaO.

 Q 10 Chemical composition of some matter is given in the following table. Identify the main type of matter from them.

 

Name of matter

 

Chemical composition

Main type of matter

 

Sea water

 

H2O + NaCl + MgCl2 + ...

 

Mixture

 

Distilled water

H2O

 

Compound

Hydrogen gas filled in a balloon

H2

Element

 

The gas in LPG cylinder

C4H10+C3H8

Mixture

 

Baking soda

NaHCO

Compound

Pure gold

Au

Element

 

The gas in oxygen cylinder

O2

Element

 

Bronze

Cu+Sn

 

Mixture

 

Diamond

C

Element

 

Heated white powder of blue vitriol

CuSO4

 

Compound

Limestone

CaCO3

Compound

Dilute hydrochloric acid

HCI+H2O

Mixture