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LAB MANUAL
SCIENCEFOR CLASS VII
By
Dr. N.K. Sharma
Nutan Vidya Mandir
Dilshad Garden, Delhi
Name .............................................................................................................
School ............................................................................................................
Roll No. .......................... Class ................................ Section .......................
������������� ����������BANGALORE • CHENNAI • COCHIN • GUWAHATI • HYDERABAD
JALANDHAR • KOLKATA • LUCKNOW • MUMBAI • RANCHI
NEW DELHI • BOSTON, USA
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TLM7–8452–150–COMP. LAB MAN SCIENCE VII C—5812/012/10Typeset at : Monu Printographics, Delhi Printed at : Sanjay Printers & Publishers Pvt. Ltd.
CONTENTS
Expt. Topic Page No. Date Remarks
No. Book Copy
Experiments1. To prepare an acid (sulphuric acid) 12. To show that evolved gas is hydrogen 23. To prepare a base (Magnesium hydroxide) 44. To measure the area of irregular surface 65. To measure the diameter of a ball 76. To determine the volume of an irregular
shaped body 97. To show solid form of water (ice) is lighter
than liquid water 118. To prepare a salt solution in the laboratory 129. To determine the density of water 14
10. To study the digestive system of human body 1511. To show the conduction of heat 1712. To show the convection of heat 1913. To show that liquids conduct heat 2114. Experiment to show the thermal expansion
of solids 2215. To show that carbon dioxide is produced
during respiration 2416. To show the presence of salts in water 2517. To show that light travels in a straight line 2718. To prove the laws of reflection by using a
plane mirror 2919. To prepare carbon dioxide gas in laboratory 3120. To show neutralisation reaction 33
Multiple Choice Questions 35
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AIMTo prepare an acid (sulphuric acid).
MATERIALS REQUIRED(i) Powdered sulphur, (ii) Water, (iii) Long handled spoon, (iv) Gas jar, (v) Burner.
THEORYSulphuric acid is a strong mineral acid. Its molecular formula is H2SO4. It is soluble in
water at all concentration. H2SO4 has many applications and is used in chemical industry.
PROCEDURE1. Take some powdered sulphur in long handled spoon.
2. Heat it over the flame of a burner till it catches fire.
3. Lower it in a gas jar and wait till sulphur stops burning.
4. Remove the spoon and cover the mouth of gas jar with the lid.
5. Put some water in gas jar. Water dissolves the gas.
OBSERVATIONWhen we dip litmus paper into this water, blue litmus paper turns red. It confirms the
formation of an acid.
DIAGRAM
Figure: Preparation of an acid (Sulphuric acid).
CONCLUSIONA solution is formed which is sulphuric acid and it turns blue litmus paper red.
1
2 LAB MANUAL—SCIENCE VII
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Q. 1. What is the taste of an acid ?Ans. An acid is sour in taste.Q. 2. Which acid is present in lemon juice ?Ans. Lemon juice contains citric acid.Q. 3. Which acid is present in vinegar ?Ans. Acetic acid is present in vinegar.Q. 4. Name the acid present in milk.Ans. Lactic acid is present in milk.Q. 5. Name the acid which is used in cleaning kitchen sink and sanitary wares.Ans. Hydrochloric acid.
Q. 6. Name the acid which is formed when sulphur trioxide reacts with water.Ans. Sulphuric acid.
Q. 7. Name any two strong mineral acids.Ans. (i) Hydrochloric acid (HCl)
(ii) Nitric acid (HNO3).
Q. 8. Name any one weak acid.
Ans. Carbonic acid (H2CO3).Q. 9. What is the effect on blue litmus paper, when it is dipped into H2SO4 ?Ans. Blue colour of litmus changes to the red colour.
Q. 10. What is the range of acid on pH scale?Ans. pH value of 0–7.
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AIMTo show that evolved gas is hydrogen.
MATERIALS REQUIRED(i) Zinc granules, (ii) Dil. sulphuric acid, (iii) Burner (iv) Test-tube (v) Matchstick.
THEORYHydrogen exists as diatomic covalent molecule (H2). Molecular hydrogen is also called
dihydrogen. Hydrogen gas can be prepared in the laboratory by adding dil. H2SO4 to zinc granules.
EXPERIMENTS 3
Zn(s) + H2SO4 → ZnSO4 + H2 ↑Zinc Sulphuric Zinc Hydrogen
acid sulphate gas
PROCEDURE1. Take approximately 5 ml of dil. sulphuric acid in a test-tube.2. Add few small pieces of zinc granules to it.3. Vigorous reaction starts immediately and evolution of gas is observed.4. Bring a lighted matchstick near the mouth of test-tube.
OBSERVATIONBlue flame is observed and a pop sound is produced.
DIAGRAM
Figure: Preparation of hydrogen.
CONCLUSIONThe evolved gas is hydrogen gas.
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Q. 1. Write the formula of sulphuric acid.Ans. H2SO4.Q. 2. Which gas is evolved when any reactive metal react with H2SO4 ?Ans. Hydrogen gas is liberated.Q. 3. Why copper, silver and gold do not react with hydrochloric acid ?
Ans. Because copper, silver and gold are least reactive metals.
4 LAB MANUAL—SCIENCE VII
Q. 4. Name the gas which burns with a pop sound.
Ans. Hydrogen gas burns with a pop sound.
Q. 5. What is the chemical formula of zinc ?
Ans. Zn.
Q. 6. What happens when Na reacts with H2SO4 ?
Ans. Hydrogen gas is evolved
2Na + H2SO4 → Na2SO4 + H2
Sodium Sulphuric Sodium Hydrogenacid sulphate
Q. 7. What is the molecular mass of hydrogen gas ?
Ans. H2 (1 + 1) = 2.
Q. 8. What happens when hydrogen gas is passed on litmus ?
Ans. Neutral towards litmus.
Q. 9. Name the source from which litmus solution is obtained.
Ans. Litmus solution is extracted from lichens.
Q. 10. Out of sodium and zinc which metal is more reactive with acid.
Ans. Sodium (Na).
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AIMTo prepare a base—Magnesium hydroxide (Mg(OH)2).
MATERIALS REQUIRED(i) Magnesium ribbon, (ii) Tong, (iii) Water, (iv) Test-tube.
THEORYThe hydroxide of magnesium is a base. Magnesium reacts with water to produce magnesium
hydroxide.
Mg(s) + 2H2O(l) → Mg(OH)2 + H2 ↑Magnesium Water Magnesium Hydrogen
hydroxide gas
PROCEDURE1. Hold a piece of magnesium ribbon with a pair of tongs.
2. Heat it over the flame.
3. White ash is formed and metal burns, producing a bright light.
EXPERIMENTS 5
4. Transfer the white ash into the test-tube and add 10–15 ml of water in it.
5. Heat the mixture.
6. White ash dissolves in warm water.
7. Now add few drops of red litmus.
OBSERVATIONRed litmus turns blue.
CONCLUSIONRed litmus turns blue, which indicates the formation of base.
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Q. 1. What are bases ?
Ans. Bases are those compounds which change the colour of red litmus to blue.
Q. 2. What are alkalies ?
Ans. All soluble hydroxides are alkalies.
Q. 3. Name any two bases.
Ans. (i) Sodium hydroxide (NaOH)
(ii) Potassium hydroxide (KOH).
Q. 4. Name any two weak bases.
Ans. (i) Copper hydroxide [Cu(OH)2]
(ii) Ammonium hydroxide (NH4OH).
Q. 5. Name the compounds formed when metal oxide dissolves in water.
Ans. Compound formed is hydroxide.
Q. 6. What is the taste of a base ?
Ans. Bases are bitter in taste.
Q. 7. What is litmus ?
Ans. Litmus is the natural indicator.
Q. 8. Name two synthetic indicators.
Ans. (i) Methyl orange.
(ii) Phenolphthalein.
Q. 9. What is neutralisation reaction ?
Ans. Reaction between acids and bases to give a salt and water is known as neutralisationreaction.
Q. 10. What is the range of bases on pH scale ?
Ans. 7 pH –14 pH.
6 LAB MANUAL—SCIENCE VII
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AIMTo measure the area of irregular surface.
MATERIALS REQUIRED(i) Graph paper, (ii) Leaf, (iii) Pencil.
THEORYArea. Area is a quantity expressing the two-dimensional size of a defined part of surface.
Area = Length × BreadthIt’s unit is cm2.
PROCEDURE1. Place the given leaf on the graph paper.2. Draw the boundary of the leaf with the pencil.3. Remove the leaf.4. Now count the number of complete small squares inside the outline.5. Now count squares which are more than half inside the outline.6. Those squares which are less than half and inside the outline should not be counted.
OBSERVATIONArea of the leaf = Total number of complete squares + Total number of squares which are
either half or more than half
= ........... sq. mm
DIAGRAM
Figure: Measuring area of a leaf.
CONCLUSIONArea of irregular surfaces can be measured by counting the number of squares on the graph
covered by the object.
EXPERIMENTS 7
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Q. 1. What is area ?Ans. The surface occupied by an object is called area.Q. 2. What is the S.I. unit of area ?Ans. S.I. unit of area is m2.Q. 3. Complete the following :
(i) 1 km2 = ........ m2
(ii) 1 m2 = ........ mm2
(iii) 1 hectare = ........ m2.Ans. (i) 1 km2 = 1,000,000 m2
(ii) 1 m2 = 1,000,000 mm2
(iii) 1 hectare = 10,000 m2
Q. 4. How will you find the area of irregular surface ?Ans. Area of irregular surface is measured by using graph paper.Q. 5. What is area of rectangle ?Ans. Area of rectangle = length × breadthQ. 6. Name any two things with irregular surface.Ans. Leaf, foot.Q. 7. What is the system used for measurements now-a-days ?Ans. S.I. system.Q. 8. What is measurement ?Ans. Measurement is the technique developed for correct judgement of dimensions of various
objects.Q. 9. Is the unit of area is cm3 ?Ans. No.
Q. 10. How many dimensions are used in area ?Ans. Two.
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AIMTo measure the diameter of a ball.
MATERIALS REQUIRED(i) Two wooden blocks, (ii) Metre scale, (iii) Ball, (iv) Table.
8 LAB MANUAL—SCIENCE VII
THEORYThe diameter of a ball or circle is the length of the line passing through the center and
touching two points on its edges.
Diameter can be calculated with the help of the given radiusDiameter = 2 × Radius of a ball or circle.
PROCEDURE1. Take two wooden blocks and metre scale.
2. Place a ball on the table.
3. Place the two wooden blocks such that both of these touch the ball and their upper edgesare along the metre scale.
4. Measure the distance between the faces of the block touching the ball.
OBSERVATIONDiameter of ball is ...... cm.
DIAGRAM
Figure: Measuring the diameter of a ball.
CONCLUSIONThe diameter of a ball is the length of the line passing through its centre and touching two
points on its edges.
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Q. 1. Is it possible to measure the diameter of a ball directly using metre scale and why ?Ans. Not possible, because the ball is spherical in shape.Q. 2. What is the formula for radius of the cylinder ?
Ans. r = 2d
.
EXPERIMENTS 9
Q. 3. Calculate the radius of ball having diameter 42 cm.
Ans. r = 2d
= 422 = 21 cm.
Q. 4. Can you measure the length of a pencil with metre scale ?Ans. Yes.Q. 5. What is diameter of a ball ?Ans. The diameter of a ball is the length of the line through the center and touching two points
on its edges.
Q. 6. What is the formula of diameter ?Ans. Diameter = 2 × Radius of a ball or circle.
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AIMTo determine the volume of an irregular shaped body.
MATERIALS REQUIRED(i) Measuring cylinder, (ii) Stone, (iii) Water, (iv) Thread.
THEORYWhen an object is immersed in water, water is displaced. The volume of the water displaced
can then be measured. The volume of the immersed object will be exactly equal to the volume ofthe displaced water.
PROCEDURE1. Put some water in measuring cylinder (say 50 ml).2. Tie the thread around the irregular shaped body.
3. Immerse the solid in water.
4. The level of water in the cylinder rises.
5. Note the new level of water in the cylinder.
OBSERVATIONVolume of water taken initially = x cm3
Volume of water after putting irregular solid = y cm3
Volume of irregular shape bodyV = (y – x) cm3.
So, increase in the level of water is equal to the volume of irregular body.
10 LAB MANUAL—SCIENCE VII
DIAGRAM
Figure: Measuring the volume of an irregular shaped body.
CONCLUSIONVolume of an irregular shaped body is equal to the volume of water displaced by the body.
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Q. 1. Define volume.
Ans. The amount of space that a given quantity of any substance will occupy is called volume.
Q. 2. What is the S.I. unit of volume ?
Ans. S.I. unit of volume is cubic metre (m3).
Q. 3. Complete the following :
1 m3 = ...... cm3
1 litre = ...... ml
Ans. 1 m3 = 10,00,000 cm3
1 litre = 1000 ml
Q. 4. How will you find the volume of regular solid ?
Ans. Volume of regular solid is determined by measuring its dimensions.
Q. 5. How will you express the volume of liquid ?
Ans. Volume of liquid is expressed in litres.
Q. 6. Name the commonly used submultiple of a litre.
Ans. Millilitre (ml).
Comprehensive Lab Manual ScienceClass-VII
Publisher : Laxmi Publications ISBN : 9788131809082 Author : Dr. N.K.Sharma
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