Science 2nd SemesterSTYLE OF PAPER 2014-15Q.1 MCQ 20Q.2 A Answer in one sentence (Any 15) 15 Q.2 B Define (Any 3) 3 Q.3 A Difference (Any 3) 6Q.3 B Give Reason (Any 3) 6Q.4 A Brief (Any 5) 10Q.4 B Classify 2Q.5 A Detail (Any 5) 15Q.5 B Experiment 3Ex-1 MCQL-1 1 Which gas is obtained when potassium permanganate is heated ?A Carbon dioxide B Oxygen C Hydrogen D Nitrogen2 Which of the following gases is a supporter of combustion ?A Hydrogen B Nitrogen C Carbon dioxide D Oxygen3 Which gas turns decanted limewater milky ?A Oxygen B Carbon dioxide C Nitrogen D Hydrogen4 Which gas is liberated when hydrochloric acid and marble stone react ?A Oxygen B Carbon dioxide C Nitrogen D Hydrogen5 What is the chemical name of washing soda ?A Sodium bicarbonate B Calcium carbonate C Sodium carbonate D Calcium hydroxide6 What is chemical formula of baking soda ?A NaOH B Na2CO3 C NaHCO3 D NaCl7 Which gas is used in the production of cold drinks like soda water ?A Oxygen B Nitrogen C Hydrogen D Carbon dioxide8 Which is the lightest gas ?A Oxygen B Nitrogen C Hydrogen D Carbon dioxide9 Which of the following gases is combustible ?A Oxygen B Carbon dioxide C Nitrogen D Hydrogen10 Which gas is produced when a reaction between sodium peroxide and water takes place ?A Oxygen B Carbon dioxide C Nitrogen D HydrogenL-2 1 What is the fundamental component of an element ?A Molecule B Atom C Ion D Compound2 Which particle is not in the nucleus ?A Proton B Neutron C Electron D None amongst the given3 Which particle does not possess any charge?A Proton B Neutron C Electron D None amongst the given4 Which particle is moving around the nucleus?A Proton B Neutron C Electron D None amongst the given5 What is the maximum number of electrons that can be accommodated in the first energy level of an atom?A 2 B 4 C 6 D 86 How many maximum number of electrons can be accommodated in the third energy level?A 2 B 8 C 18 D 367 What is the electronic configuration of sodium?A (2, 8) B (2, 8, 1) C (2, 8, 2) D (2, 8, 7)8What is the electronic configuration of chlorine?A (2, 8) B (2, 8, 1) C (2, 8, 7) D (2, 8, 2)9 What is the valence of magnesium?A +1 B +2 C +3+410 What is the valence of aluminum?A +1 B +3 C +2 D +411 Which of the following elements have only one ele2tron in its outermostorbit?A Sodium B Magnesium C Oxygen D Chlorine12 How many electrons are present in the outermost orbit of chlorine?A 1 B 3 C 5 D 713 The atomic number of Silicon is 14. What is its electronic configuration?A (2, 8) B (2, 8, 4) C (2, 8, 3) D (2, 8, 7)L-3 \1. Which of the following elements is a metal ?A. Carbon B. Sulphur C. Phosphorous D. Calcium 2. Which metal exists in molten state at room temperature ?A. Sodium B. Magnesium C. Mercury D. Aluminium3. Which metal can be easily cut by knife ? A. Iron B. Copper C. Magnesium D. Sodium 4. Which of the following elements possesses the property allotrophy ?A. Potassium B. Phosphorous C. Iron D. Magnesium 5. The reaction of magnesium with which of the following results in the release of hydrogen ?A. Chlorine B. Oxygen C. Hydrochloric acid D. Sodium hydride6. How many atoms are present in one molecule of phosphorus ?A. 2 B. 4 C. 6 D. 87. Which allotrope of phosphorus is used in the making medicine for killing rat ? (rodenticide) ?A. Aluminium phosphide B. Phosphorus pentachloride C. Zinc phosphide D. Phosphorus pentoxide8. What are the constituents of bronze ?A. Copper and zinc B. Copper and tin C. Copper and nickel D. Copper and lead 9. How many atoms are present in one molecule of carbon dioxide ?A. two B. Three C. Four D. Five 10 What is the molecular formula of ammonia ?A. Pcl5 B. NH3 C. N2O5 D. alcl3L-41. At which point on the principal axis does the incident rays parallel to the principal axis meet?A. Optical centre B. Centre of curvature C. Focal point D. Any point on the principal axis2. Where is the image formed , when an object is kept beyond 2f in front of convex lens?A. Beyond F and 2F B. At 2F C. Between F and 2F D. At F 3. where should be an object kept in front of convex lens such that the final image formed is real and magnified?A. Between F and 2F B. At 2F C. Beyond 2F D. Between F and P 4. Where should be an object kept in front of convex lens such that final image formed is virtual? A. At 2F B. Beyond 2F C. Between F and 2F D. Between F and P 5. Where is the image formed when an object is kept at 2F in front of a convex lens?A. Beyond 2F B. At 2F C. Between F and 2F D. At F 6. Which type of image can never be formed by a convex lens?A. Real and diminished B. Real and magnified C. Virtual and diminished D. Virtual and magnified 7. What is the nature of the image formed by a concave lens?A. Virtual , erect and diminished B. Real and magnified C. Virtual , erect and magnified D. Real , inverted and magnified L-61. What is the name of the process by which the glucose molecules in our body cells liberate heat by reacting with oxygen?A. Rapid combustion B. Slow combustion C. Incomplete combustion D Complete combustion2. Which of the following is a combustible substance?A. Stone B.Glass C. Asbestos D. Wood3. Which of the the following is not used in extinguishing fire?A. Sand B. Water C. carbon dioxide D. Oxygen4. What is the color of the outmost zone of the candle flame where complete combustion takes place?A. Blue B. Black C. Yellow D. RedL-71. Which of the following is not a fossil fuel ?A Wood B Mineral coal C PetroleumD Natural gas2. Which variety of coal is ranked the best ?A Peat coalB Lignite C Bitumen coal D Anthracite3. At what temperature range is petrol obtained in the fractional distillation of petroleum ?A Between 120o C to 180o C B Between 180oC to 260o C C Between 260o C to 340oCD Between 30oC to 120oC4. At what temperature range is kerosene obtained during the fractional distillation of petroleum ?A Between 30oC to 120oC B Between 120o C to 180o C C Between 180oC to 120o CD Between 260o C to 340oC5 At what temperature range is diesel obtained during the fractional distillation of petroleum ?A Between 30oC to 120oC B Between 120o C to 180o C C Between 180oC to 260o CD Between 260o C to 340oC6. What is obtained in the uppermost part of fractional distillation tower ?A Diesel B Petroleum gas C Petrol D Fuel oil7. Which constituent of petroleum is used for making grease ?A Naphtha B Lubricant oil C fuel oil D TarL-8 Q.1 MCQ 1. Which type of energy source is the sun ?A. Non-renewable source of energy B. Exhaustible energy source C. Energy source producing pollution D. Inexhaustible source of energy2. What is the temperature that can be attained in the box of a solar cooker?A. 100C to 400 C B. 400C to 600 CC. 600C to 800C D. 1000 C to 1400 C3. What is the principle of a solar cooker ?A. Conversion of solar energy into electrical energyB. Conversion of solar energy into heat energyC. Conversion of heat energy into solar energy.D. Conversion of solar energy into mechanical energy4.Which element is used in a solar cooker?A.Uranium B.AluminiumC.Silicon D. Sodium5. Which of the following solar equipment does not convert solar energy into heat energy?A. Solar cooker B. Solar water heaterC. Solar dryer D. Solar cell6. Where is the largest solar park of asia located in Gujarat?A. Charanka village of patanB. Kalayanpura village of kheda districtC. Chor-Dungri village of kheda districtD. Raliyati gurjar village of panchmahal districtL-9 1.Which of the following pollutes the soil to the maximum extent?A.Paper B. Excreta of animals C. Plastic D. The remains of trees2.Which garbage gets degraded very fast?A. Leftover food B. Plastic C.Waste metal D. Pieces of wood3.What is the time required for the degradation of plastic?A. 3-4 weeks B. 8-10 weeks C. 8-10 years D. 8-10 lakh years4.Which of the following is e-waste?A. Waste cassette B. Used syringe C. Blood sample D. Waste plastic bag5.While collecting biomedical waste , the plastic waste is to be put in which colour dustbin?A. Green B. Red C. Yellow D. Blue (or white)EX.2 ANSWER IN ONE SENTENCEL-1 1.By what other name is oxygen gas known as?A.1 Oxygen gas is known as vital gas.2.Cylinders of which gas are carried by mountaineers?A.2 Cylinder of oxygen gas is carried by mountaineers.3.What is the molecular formula of carbon dioxide gas?A.3 The molecular formula of carbon dioxide gas is co2.4.What happens when a burning candle is inserted in a gas jar filled with carbon dioxide gas?A.4 When a burning candle is inserted in a gas jar filled with carbon dioxide gas the burning candle extinguishes.5.What is another name of carbon dioxide gas?A.5 The another name of carbon dioxide gas is fire gas.6.What is the solid form of carbon dioxide called?A.6 The solid form of carbon dioxide is called dry ice.7.What is the chemical formula of baking soda?A.7 The chemical formula of baking soda is sodium bicarbonate NaHCO3.8. Which gas burns with an explosion?A.8 Hydrogen gas burns with an explosion.9.Which gas is filled in balloons used for atmosphereic study?A9.Hydogen gas is filled in balloons used for atmosphereic study.10.Which gas is produced when a mixture of ammonium chloride and sodium nitrite is heated?A.10 Nitrogen gas is produced when a mixture of ammonium chloride and sodium nitrite is heated.L-2 1.What is the basic unit of a compound?A.1 The basic unit of a compound is molecule.2. What is the type of electric charge on a proton?A.2 The type of electric charge on a proton is positive.3. Which particle in an atom carries negative charge?A.3 Electron in an atom carries negative charge.4. What is the atomic number of magnesium?A.4 The atomic number of magnesium is 12.5. The atomic number of aluminium is 13. What is its electric configuration?A.5 Aluminiums electric configuration is (2,8,3).6. The atomic number of sulphur is 16. What is its electric configuration?A.6 Electric configuration of sulphur is (2,8,6).7. What is the electric configuration of positive sodium of ion (Na+)?A.7 The electric configuration of positive sodium of ion (Na+) is (2,8).8. What is the chemical formula of common salt?A.8 The chemical formula of common salt is NaCl.9. What is circular central portion of an atom called?A.9 Circular central portion of an atom called is Nucleus.10. How many electrons are present in the outermost energy level (orbit) of an oxygen atom?A.10 The outermost energy level (orbit) of an oxygen atom is 6 electrons.L-3 1. Write the name of two crystalline allotropes of carbon .A. Two crystalline allotropes of carbon are Graphite and Diamond2. Which elements have a strong tendency of forming positive ions ?A. The elements that has 1, 2, or 3 electrons in the outermost energy level have a strong tendency of forming positive ions.3. What is formed when sodium reacts with hydrogen gas ?A. Sodium reacts with hydrogen gas to form sodium hydride.4. Which gas is produced when aluminium reacts with hydrochloric acid ?A. When aluminium reacts with hydrochloric acid hydrogen gas is produced.5. Which compound of phosphorous is used for preserving grains ?A. Aluminium Phosphide is used for preserving grains.6. Write the uses of Phosphorous.A. Red phosphorous is used to prepare match sticks , crackers , explosives and even insecticides . Compound of such as zinc phosphide to prepare and kill rats.7. What are the constitutions of stainless steel ?A. The constitutions of stainless steel are chromium , nickel ,Iron.8. What is the full name of NaCl ?A. The full name of NaCl is Sodium Chloride.9. What is ionization ?A. The process of losing electron by an atom of a metal or gaining electron by an atom of a nonmetal is ionization.10. In what is the purity of gold measured ?A. The purity of gold is measured in carats.L-4 Q1. What do you mean by a concave lens?A1. The lenses for which both the surfaces are curved inward is called concave lens.Q2. Where should an object be placed in front of convex lens such that the final image is real and is of the same size as that of the object?A2. At 2f an object should be placed in front of convex lens such that the final image is real and is of the same size as that of the object.Q3. What is the nature of the image formed when an object is placed between focal point and optical of a convex lens?A3. The image formed when an object is placed between focal point and optical of a convex lens is virtual , erect and larger than the objectQ4. What is the nature of the image formed when an object is placed at the focal point of a convex lens?A4. when an object is placed at the focal point of a convex lens the image is formed at infinite and the image is real , inverted and highly magnified.Q5. Write the name of instruments in which concave lens is used? A5. Concave lens is used for making spectacles for near sightedness and in door holes.Q6.Where is telescope used?A6. 1) Telescope is used in the study of astronomy 2) One can study planets , stars , moon and entire solar system.L-5 Q1. Which is the main organ of the male reproductive system?A1. Testis is the main organ of the male reproductive system.Q2. Which organ produces sperms?A2. Testis produces sperms.Q3. At what age does boys attain puberty?A3. At the age of 13-14 years boys attain puberty?Q4. In which organ does the fertilization of ovum takes place?A4. The fertilization of ovum takes place in oviduct.Q5. In which organ is the zygote implanted where it gets developed ito a child?A5. Uterus organ is the zygote implanted where it gets developed ito a child.Q6. What is the newly developed ovum after meeting with the embryo called?A6. The newly developed ovum after meeting with the embryo is called zygote.Q7. Where are the kidneys located in the human body?A7. The kidneys are located on the lateral side of the vertebral coloumn in the back region.Q8. What is the colour of kidney?A8. The colour of kidney is dark brown.Q9. Where is urine produced by the kidneys stored?A9. Urine produced by the kidneys is stored in urinary bladder.Q10. What are the constituents of urine?A10. The constituents of urine are urea, uric acid, ammonia and water.L-6 Q.1 What do you mean by combustible substances?A.1 A substance which catches fire is called combustible substance (eg) wood, paper, etc.Q.2 What is the color of the flame when a substance undergoes incomplete combustion?A.2 The color of the flame is yellow when a substance undergoes incomplete combustion.Q.3 Which portion of the flame does a goldsmith use with the help of a blowpipe while making ornaments?A.3 Goldsmith make use of central portion of flame while making ornaments.Q.4 What is the full form of LPG?A.4 The full form of LPG is Liquefied Petroleum Gas.Q.5 In which type of combustion heat is produced but light is not produced?A.5 In slow combustion heat is produced but light is not produced.L-7 Q1. Which variety of coal is ranked the lowest ?A1. Peat is ranked the lowest.Q2. Which variety of coal is used in the thermal power station and railways ?A2. Lignite coal is used in the thermal power station and railways.Q3. At what temperature is petroleum heated before it is sent in the fractional distillation tower?A3. Petroleum is heated at 450oC temperature before it is sent in the fractional distillation tower.Q4. Between what temperature range is naphtha obtained during the fractional distillation of petroleum ?A4. naphtha is obtained in the distillation of petroleum between 120oC to 180oCQ5. What is obtained in between temperatures 260oC to 340oC is the fractional distillation tower in the fractional distillation of petroleum?A5. Diesel is obtained in between temperatures 260oC to 340oC is the fractional distillation tower in the fractional distillation of petroleum.Q6. What are the uses of petroleum gas ?A6. The uses of petroleum gas are 1. In the fractional distillation first of all at 25o C, petroleum gas is separated. 2. Mainly it is used in vehicles and as a feul for cooking food it is known as L.P.G.Q7. Due to which gases in the exhaust of the vehicles the atmospheric pollution has increased?A7. The atmospheric pollution has increased due to sulphur dioxide , oxides of nitrogen and carbon monoxide present in the exhaust of the vehicles.L-8 Q1. In what form is the energy supplied by the sun to us? A1. The sun Supplies us light energy. Q2. For how many more years will the sun supply energy to us? A2. The Sun will supply energy to us for 4.5 billon years. Q3. Why is the box of a solar cooker coloured black?A3. The box of a solar cooker is coloured black because black surface absorbed more heat energy.Q4. Why is mirror fitted in the lid of the box of a solar cooker? A4. Mirror lid fitted in the box of a solar cooker so that it reflects the sunrays inside the box. Q5. What is a solar cooker used for? A5. A solar cooker is used for: 1) To roast or to dry food. 2) To cook pulses and rice. Q6. Why is the copper pipe used in a solar water heater wounded in the form of a coil? A6. The copper pipe is used in a solar water heater wounded in the form of a coil because in coil shape copper tube the area of absorbing heat increased. Q7. Which equipments converts solar energy into electrical energy? A7. Solar cell converts solar energy into electrical energy. Q8. What type of current is produced by a solar cell? A8. A solar cell produced only DC current.Q9.Which solar equipment is used to drying grains? A9. Solar dryer is used to dry grains. Q10. Which place in the kheda district has a solar power plant having a capacity of eight kilowatt? A10.Kalyanpura village in the kheda district having a capacity of eight kilowatt. Q11. What do you mean by a solar panel? A11. When so many solar cell is connected in a series is called a solar panel.L-9 Q1. What do you mean by pollution?A1. The undesirable, physical, chemical all biological changes occuring in air, water or on land is called pollution.Q2. What happens if we throw , bury or burn plastic anywhere? A2. Heaps are seen of plastic on roads, riverbanks get choked up of drainage system is caused. animals eat such and diseases are caused. burning of it releases poisiones gases in the air.inhaling such air causes respiratory system. Q3.What are the useful things that can be made from used plastic bags after cleaning them?A3. The used plastic bag can be utilized to make door mat , sitting mat , or thread for the cots , choclate wrappers or biscuits can be used to prepare toran.Q4.How will students celebrate 'No Plastic Day'?A4.Students and teachers will not use plastic in the school as well as at their home on this day. Q5. Go to a place near your society where plastic waste is thrown. Dig the ground there and find a piece of plastic. Examine it and note down what is the effect on that particular piece.EX.3 DEFINEL-2 1 Element- A group of similar atom is called element.2 Atomic Number- The number of protons and element present in the atom of an element is called Atomic number.L-3 1 Oxidation The chemical process in which either oxygen is added or hydrogen is removed is Oxidation.2 Reduction The chemical process in which either hydrogen is added or oxygen is removed id Reduction.3 Reactants Atoms of molecules taking part in any chemical reaction are called ReactantsL-4 1)Centre of curvature : curved surface of lens are part of two spheres , the centre of that sphere are called centre of curvature of the lens.2)Radius of curvature : the radius of the sphere of which curved surface of lens is a part , is called radius of curvature.3)Focal length : the distance between optical centre and focal point is called focal length.L-5 1. Reproduction: the natural process in which organism of one 's species produced a new organism of its own species is call reproduction.2. Excretion: the removal of useless , harmful liquid substance from our body is called excretion.L-6 1. Combustion: A chemical process in which a substance reacts with oxygen and produces heat and light is called combustion.2. ignition point: A substance catches fire at definite temperature, this temperature is called ignition point.3. Complete combustion: When a substance get sufficient amount of oxygen it burns with a blue flame it is called complete combustion (eg) combustion of L.P.G.Ex-5 DifferenceL-1 Oxygen and Carbon Dioxide1 It supports combustion1 It does not supports combustion but it extinguishes fire.

2 It is an element2 It is a compound

3 It does not effect red or blue litmus paper3 It turns moist blue litmus paper red.

L-2 1. Molecule and Atom

MoleculeAtom

Molecule is the fundamental unit of a compound.

Atom is the fundamental unit of an element.

Molecules exist independently.It does not exist independently.

It is made up of one or more type of elements.It is made up of only one type of element.

2. Atom and IonAtomIon

Atom is electrically neutral.

Ion is not neutral but positively or negatively charged.

An atom is chemically active.Ion is chemically inactive.

3. Proton and ElectronProton is positively charged.

Electron is negatively charged.

It lies in the nucleus.It circulates around the nucleus in the energy levels.

L-3. 1. Metals And Non-metalsMetalNon metals

Metals are in solid form (except mercury).Non-metals are in solid, liquid or gaseous forms.

Metals are malleable.Non-metals are not malleable.

Metals are good conductor of heat and electricity.

Non-metals are bad conductors of heat and electricity.

Metals have luster.

Non-metals are lusterless.

Most metals are heavy in weight.

Most non-metals are light in weight

L-4

Convex lens Concave lens

1. lens for which both the surfaces are curved outward is called convex lens.1.lens for which both the surfaces are curved inward is called convex lens.

2.It is thicker in the middle than the edges. 2. It is thinner in the middle and thicker at edges.

3.It is convergent lens 3. It is divergent lens

L-5 TESTISOVARIES

1. It is male reproductive organ.1. It is female reproductive organ.

2. It produces sperms.2. It produces ovar.

L-6Complete combustionIncomplete combustion

1.When a substance get sufficient amount of oxygen it burns with blue flame it is called complete combustion1.When a substance does not get sufficient oxygen and burns with yellow flame is called Incomplete combustion.

2. Eg combustion of LPG

2. Eg combustion of wood

3. They donot spread pollution

3. They spread pollution

Complete combustion 1.When a substance get sufficient amount of oxygen it burns with blue flame it is called complete combustion 2. Eg combustion of LPG3. They donot spread pollutionIncomplete combustion1.When a substance does not get sufficient oxygen and burns with yellow flame is called Incomplete combustion.Eg combustion of wood They spread pollution

L-7 Lignite Anthracite

1. It is brown or grey in colour.1. It is hard and black in colour

2. It is smoky and makes plenty of ashes 2. It is the best quality of coal

3. It is used in thermal power stations and railways

3. It is used in house and industries

2. petrol Diesel

1. Petrol is seprated at 30C to 120C1. Diesel is seprated at 260C to 340C

2. It is used as fuel in vehicles 2. It is used as fuel in vehicles like truck and tractor

3. It is highly inflammable 3. It is less inflammable than petrol

EX.5 GIVE REASONSL-1 1. Hydrogen gas is filled in ballons because hydrogen is lighter gas as compared to air.when a balloon inflated with hydrogen gas.it becomes lighter than air.when this balloon is realesed it rises high up in the sky hence, hydrogen gas is used in the balloons that are to rise up in the sky.L-2 1. An atom is electrically neutral because 1)positively charged protons are present in the nuclears of atom. 2)negatively charged electrons revolve around the nucleas in the definite circular orbit. 3) in an atom of any element the numbers of proton is equal to the numbers of electrons so the total positive charge is equal to the total negative charge hence,an atom is electrically neutral.2. Helium and neon gases are chemically inert because helium and neon have the outermost orbit filled due to this fully filled orbit helium and neon can not accept or donate electons with atoms of any other elements so they are chemically inertL-3 1 Small amount of copper is added to gold and silver while making jewellery because the ornament make from pure gold such that if pressure is exerted from on them their shape changes so pure gold is mixed with metals such as silver , cooper or zinc to make it strong and durable.2 Stainless steel is used for making household utensils because it is an alloy made up of iron, chromium, nickel. It is corrosion resistant. It is hard and strong. Stains of food items can be removed easily on washing it. It shows lustre so its utensils looks attractive.L-61. When a paper cup filled with water is hearted over a candle flame the paper cup does not burn because if the temperature of the substance does not reach till its ignition point, the substance doesnot start burning. Due to this reason the cup doesnot start burning as long as there is water in it.2. Fir caused due to petrol cannot be extinguished by water because by this way fire doesnot extinguishes. Petrol is lighter than water so it floats on water and spread. If water is used there is a risk of getting burn.L-7We must use substance like petrol diesel sparingly and very judiciously because - petroleum is non-renewable source of energy it takes millions of year to form the stock of petroleum is limited so if we make extravagant use of item there is probability that it will be exhausted in near future further use of these substance increase pollutionL-8 1. Copper pipe used in a solar water heater is wound in the shape of a coil. Because in coil shape cooper tube the area of absorbing heat increased.L-9 1. It is our moral duty to conserve the environment - because 1. men's existence is due to environment 2. he fulfills all his economic needs from environment 3. it gives in shelter, food, water, air, minerals, etc 4. harm to environment means harm to manland 5. disturbance in environment causes many problems 6. problems of clean air and water, shortage of food and fodder, death of animals due to inbalance in environmental change are all caused due to harm caused to environment 7. hence to live a good life and to save future generation, it is our moral duty to conserve the environment.Ex-6 Answer in BRIEFL-1 Q1 Write the physical properties of oxygen gas.Ans. The physical properties of oxygen gas are as follows :-Oxygen is colourless , odourless and tasteless.It is sparingly soluble in water.It helps in combustion.Q2 Write two uses oxygen gas?Ans. Uses of oxygen gas:1. It is used for respiration2. Dissolved oxygen is used by aquatic plants and animals.3. Hand pumps preparing oxygen is used by the patients suffering from pneumonia and lung diseases to get instant relief.4. Oxygen is used to prepare flames having high temperature like oxyhydrogen flame (28000C) and oxyacetylene flame (3100oc-33000c) which is used to cut or join metals together5. It is very necessary in the production of chlorine, nitric acid and sulphuric acid.Q3 Write two physical properties of carbon dioxide gas.Ans. Two physical properties of carbon dioxide gas are1 It is colourless, odourless, tasteless.2 It is sparingly soluble in water.3 It is heavier than other gases.Q4 write the chemical properties of carbon dioxide.Ans. The chemical properties of carbon dioxide are as follows :-When carbon dioxide reacts with calcium hydroxide, calcium carbonate and water are formed. Ca(OH)2 + Co2 CaCo3 + H2OWhen carbon dioxide reacts with calcium carbonate and water, calcium bicarbonate is formed. CaCo3 + H2O + CO2 Ca(HCO3)2When carbon dioxide is heated with water at high pressure , carbonic acid is produced. CO2 + H2O H2CO3 .Q5 Write two chemical properties of carbon dioxide gas.Ans. uses of carbon dioxide gas:1. It is used by the vegetation2. It is used for extinguishing fire.3. It is used in bringing fermentation for idli, dhosa, etc.4. It is used for the preparation of cold drinks like soda water.5. solid carbon dioxide is known as dry ice. It is used as a cooling agent6. It is used for the preparation of washing soda (sodium carbonate)7. It is used for the preparation of baking soda (sodium bicarbonate) useful in cooking.Q6 Write two physical properties of hydrogen gas?Ans. The physical properties of hydrogen are :-It is colourless , odourless and tastelessIt is lighter than other gases.It is inflammable (combustible)Q7 Give two uses of hydrogen gas?Ans. 1. Hydrogen gas is used as fuel and also it is used to obtain electricity.2. it is lighter then air, hence this gas is used in the balloons which are used for the study of the atmosphere above air level.Q8 Give two uses of nitrogen nitrogen?Ans. 1. It is used to prepare chemicals like ammonia, nitric acid, calcium cyanamide, urea, etc.2. It is used to prepare inert atmosphere example on the inflammable liquids, instead of air, nitrogen gas should be filled so that there is less possibility of fire.3. It decreases the reactivity of oxygen in air.4. In films, dramas to show unnatural smoke or clouds, nitrogen gas is used.5. The roots of the plants like peas make use of the nitrogen from the air and produce food containing plenty of protein.6. It is filled in the tubes of the tyres of some of the vehicles.L-Q2. What is meant by atomic number? Explain it with example.Ans. The number of proton (p) or electrons (e) in an atom is called the atomic number (z) of an atom. Eg.Atomic number of helium (He) is 2. therefore it will have 2 protons and 2 electrons.Atomic number of Carbon (C) is 6. Therefore it will have 6 protons and 6 electrons.L-32 Explain the reaction of metals with oxygen with the help of an example.Ans When metals react with oxygen metal oxides are formed2Mg + O2 gives 2MgOQ3 Explain the reaction of metals with acids with the help of an exampleAns Most of the metals react with acids . During the reaction , Hydrogen from acid is liberated as gas. If a magnesium strip is dipped in acid , some bubbles come out it is hydrogen gasMg + 2HCl gives MgCl2 + H2Q5 Write two uses each of diamond and graphite.Ans. Two uses each of diamond is1 Used as ornaments2 Used as glass cutterGraphite1 Used to make fincals2 Used as electrode polesQ8 Explain with examples the process of oxidation with the help of an example.Ans. The chemical process in which either oxygen is added or hydrogen is removed is called Oxidation. Eg. 2H2+O2 2H2O (Addition of oxygen in hydrogen)Q9 Explain the process of reduction with the help of an example.Ans The chemical process in which either Oxygen is removed or hydrogen is added is called reduction. Eg. H2 + CuO Cu + H2OQ3. Give name of instruments used in our day-to-day life in which convex lens is used.A3. 1) Spectacles for far sightedness. 2) In magnifying lens. 3) In telescope , microscope , binocular. 4) In film projector. 5) In camera. Q4. What are the uses of telescope?A4.The uses of telescope are 1) Telescope is used to study sky and celestial body like planets ,stars , etc. 2) Simple telescope is used to see distant object nearer and clearer.Q5. What do watch repairer use a convex lens for? A5. Watch repairer use a convex lens because when the minute parts of watch are placed between convex lens and its focal point they appear magnified so the watch repairer can repair the watch easily using a convex lens L-5 Q1. Write the names of the organs of the male reproductive system.A1. The names of the organs of the male reproductive system are testis , vas deferens , seminal vesical , prostate gland , penis.Q2. Write the names of the organs of the female reproductive system.A2. The names of the organs of the female reproductive system are ovary, uterus, oviduct, cervix, vagina.L-6 Q.1 Write three condition necessary for the combustion of a substance.A.1 For the combustion of a substance three matters are required:-1. It should get oxygen of air continuously.2. The substance should attain definite temperature .3. It should get sufficient amount of fuel.2 What will you do if a fire has broken out in the house of your neighbor?A If a fire has broken out in the house of your neighbor 1 I will call fire brigade 2 I will pour water or use any fire extinguisher I will use it3 I will help people caught in the fire and sent them to the hospital if required.3 Why is water not used to put off the fire caused due to electricity ?A Water not used to put off the fire caused due to electricity because it conduct electricity and there is a risk of getting electric shock.4 In which place do we find fire extinguisher ?A We find fire extinguisher in schools, malls, offices, petrol pump, airport, railway station.5 Which substances are used to extinguish fire?A Substance like water , soap foam , sand, thick cloth, or mattress and carbon dioxide gas to extinguish fire.6 Why do we have holes in the formation of lantern/gas stove?A Lantern/gas stove fuel is used to produce fire . the holes in the lower part helps to provide continuous supply of air so that the fire burns continuously without producing smoke.7 Why are LPG/PNG fuels better than other fuels for cooking?A LPG/PNG fuels undergo complete combustion and produce more heat, No smoke is produced, when this burned . Hence there is no pollution.2. How did mineral coal formed?A. Millions of year ago vegetations like plants and trees were buried under the earth. Due to the natural process and because of high pressure and high temperature under the earth they were compressed and converted to mineral coal.3. State the types of mineral coal?A. There are 4 types of mineral coal they are 1.Peat coal 2.Lignite coal 3.Bitumen 4. Anthracite5. Which substance are obtained by the fractional distillation of petroleum?A. substance are obtained by the fractional distillation of petroleum are petroleum gas, petrol, naphtha, kerosene, diesel , lubricating oil, fuel oil and tar.L-8Write two limitations of a solar cooker.A2. Two limitations of a solar cooker are:Food cannot be prepared on cloudy day and at night.Time required to cook food is more.Q.3 What are the benefits of a solar heater?A3. The benefits of a solar heater are:Maintenance cost is negligible.Does not cause pollution.Hot water is available 24 hours a day.Q.4 Write four uses of a solar cell.A4. Four uses of a solar cell are:Useful in clock, calculator and toys.To operate traffic signal To operate street lightTo operate electrical instruments in artificial satellite.To produce electricity at interior place where transmission of electricity is not possible or transmission is costly.Recently car operated color solar cell is developed.Q.8What are the limitations of a parabolic solar cooker?A8. The limitations of a parabolic solar cooker are :Food can not prepared on cloudy day and at night.Time required to cook food is more.L-9 Q1. What do you do with the plastic waste after use? A1. The used plastic bag can be utilized to make door mat , sitting mat , or thread for the cots , choclate wrappers or biscuits can be used to prepare toran.Q2. Note the names of electronic items you know.A2. Electronic item contain circuit, I.C, etc refrigerator , T.V, washing machine, computer calculator etc are the names of electronic item.Q3. What all things come in e-waste?A3. Things that come in e-waste are useless C.D, old T.V, old computer, old mobile, old radio, old calculator, broken cacets .Q7.Which things are included in biomedical Waste?A7. Things like syringe, needle, scalpel, slides, Scissors, blood bottles, medicines, urobag catheter , x-ray film, operation equipments are used scissors, cotton, bandages etc are included in biomedical waste.Q8. What happens if biomedical waste is not disposed of properly?A8. Things like dressing material, blood samples, urine samples, removal tumor or organs are capable of spreading micro organisms .they pollute air, water and soil. they spread diseases and harm public health.EX. 7 CLASSIFYL-3 Metals-Sodium, silver , mercury, magnesium, aluminium, calcium.Non-Metals-Carbon, Sulphur , Phosphorous, Oxygen, Chlorine, IodineL-6 Combustible substances : Cardboard , Wood , sulphur ,phosphorous , coal , petrol , hydrogenNon- combustible substances : iron strip , copper strip , glass , mud , stone , water ,carbon dioxideAnswer in DetailQ9. What happens when a smouldering incense stick is inserted in a test tube filled with oxygen gas and kept for some time in the test tube? Make your observation and note it down.What is the reason behind this?A9.When a smouldering incense stick is inserted in a test tube filled with oxygen gas it start burning with flame because oxygen is a supporter of combustion and hence supports in combustion of object . due to this it starts burning faster and easily when inserted in the test tube filled with oxygen. As a result smouldering incense stick starts burning with flame.2 Q1 Explain structure of an atom in short.Ans. Atom is the fundamental component of an element, It is very minute. The circular central portion of an atom is known as nucleus. It is also known as the centre of atom. There are two types of particles namely neutron and proton in the centre of an atom which is called nucleus. The particles known as electron move around the nucleus in the definite circular path.Q3 Explain the transformation of sodium atom in positive ion of sodium ?Ans. The atomic number of sodium is 11, therefore electron configuration is(2, 8, 1) . Its outermost energy level has only one electron to complete the energy level. It hs a tendency to lose 1 electron . Due to the loss of an electron with the regards the nuclear charge, it does not remain neutral but it becomes positively charged. Therefore it is called positive ion of sodium. Na gives Na+ + e-(2, 8, 1) (2, 8) 1 freeSodium Sodium positive electronQ4. Explain the formation of oxygen molecule (O2).A4. The electronic configuration of oxygen is (2,6).the outermost orbit contains 6 electrons. to complete the energy level, it gains 2 electrons. So, both the oxygen atom shares 2 electrons each and complete the energy level having 8 electrons and make oxygen molecule.Q5. Explain the formation of nitrogen molecule (N2).A5. The electronic configuration of nitrogen is (2,5). This means its outermost orbit contains 5 electrons. to complete its obtact and become stable, it requires 3 electron. Therefore both nitrogen shares 3 electrons and complete the energy level having 8 electrons and form nitrogen molecule (N2) electronQ1 Write four physical properties of metals.Ans Physical properties of metals are as follows :-1 They have a shiny and bright surface with a metallic luster.2 They can be hammered into a thin strip (malleability).3 Metals can be drawn into thin wires.4 On striking , it produces ringing sound.5 They are good conductors of heat and electricity.6 Melting points are very high.7 Metals are usually solids, Exception mercury is the only metal found in liquid forms8 Generally metals are heavy, yet sodium, potassium, magnesium and aluminium are light metals.Q4 Write the uses of metals.Ans. The uses of different metals are as follows:-1] Iron In vehicles, bridges, pipes, nails, etc.2] Copper In wires, vessels, etc.3] Gold In gold ornaments, idols and medals.4] Silver In ornaments, currency coins and notes, vessels, etc.5] Aluminium In wires, vessels, coins, etc.6] Sodium In salt, street lights, etc.7] Potassium In fertilizers, crackers, insecticides, etc.8] Mercury In thermometer and mercury-vapour lampQ6 Write the uses of PhosphorousAns. Red phosphorus is used to prepare match sticks, crackers explosives and even insecticides. Compounds of phosphorus are used such as:-A] Zinc phosphide to prepare drugs to kill rats.B] Aluminium phosphide for preserving grains.C] Phosphorus pent oxide as a strong absorbent of humidity.Q7 Write the uses of sulphurAns. Uses of Sulphur are:-A] To prepare sulphuric acid.B] In the gun powder for preparing crackers.C] For the preparation of explosives.D] For the preparation of insecticides and fertilizers.E] For the preparation of cream for skin diseases and disinfectants.F] For vulcanization of rubber.Q10. Discuss about oxidation and reduction in the chemical process given below: H2 + CuO gives Cu + H2OHydrogen copper oxide copper waterA10.In the reaction oxygen is added in H2 and water is formed. This is oxidation reaction. Oxygen is removed from CuO and Cu is formed. This is called reduction reaction. In one reaction both oxidation and reduction takes. Hence, this reaction is called redax reaction. L-4 Q1. How is a point like image of the sun obtained using a convex lens? Explain.A1. 1) Take a convex lens. 2) Hold it in such a way that sunrays are incident on it and concentrate at a point on white paper. 3) Here convex lens is used to converge the sun rays and to obtain point like image of the sun Q2. Explain the formation of image by a concave lens with the help of a figure.A2. When an object is at any distance in the front of the concave lens , the emerging rays do not meet but diverge with respect to principal axis. So image formed by concave lens is always virtual , erect and smaller than the object.Q3. Explain the role of lungs in the excretory system.A3. During respiration carbon dioxide and additional humidity is eliminated by lungs through exhalation. some amount of water in form of humidity is release .this elimination is lesser when the atmosphere is humid such as monsoon but it is high during the cold and dry season.L-7 1. What do you mean by fossil fuel? how many types of fossil fuels are there?A. Millions of years ago plants and animals either living or dead were buried under the earth due to the heat and the pressure of earth crust they were converted into fossils. The fuel formed form such fossils are called fossil fule. There are mainly three types of fossil fuels 1.Mineral coal 2.Petroleum (mineral oil) 3. Natural gas.4. How is petroleum formed in the earth crust?A. On the earth many times there were very big storms in the oceans due to this in the coastal area the microscopic aquatic creatures were buried under the soil of the ocean under the high pressure and under the high temperature of the earth they were converted into petroleum.6. How can we use the substances like petrol and diesel judiciously?(Give three points)A. substances like petrol and diesel judiciously should be used 1. For walking distance vehicles running on petrol and diesel should not be used 2. switch off the engine of the vehicles when you are waiting on the traffic signal 3. Instead of personal vehicles use public transport 4. The engine of the vehicles should be serviced regularly 5. Vehicles having high mileage and high efficiency should be used. Write four benefits of using a solar cooker.A1. Four benefits of using a solar cooker are:Fuel is not required.Pollution free Maintenance cost is less.Vitamins are not destroyed nutrients are retained and we get natural taste.During cooking of food no need to take care of it.Write four limitations of a solar cell.A5. Four limitation of a solar cell:Silicon used to make solar cell is available in limited quality.Technology to purity silicon is very costly.Solar cells are connected with each other by silver which is costly.Limitations of storage cell restrict the storage of solar energy.

Write the benefits of usage of solar equipments.A6. The benefits of usage solar equipments are :Use of solar equipments does not cause any kind of pollution.Solar energy required for solar equipment is inhaustible.To run solar equipments accepts solar energy no other fuel is required.Solar energy is available free of cost.Maintenance cost of solar equipment is very low.To overcome the demand of energy supply fuels like petrol, diesel, kerosene, etc are used extensively.These are exhaustible sources that produce pollution.

What are the uses of solar dryer and parabolic solar cooker?A7. Solar dryer grains, fruits, vegetables are dried and dried fruits can be stored for long time. Parabolic solar cooker: Used for cooking food and roasting.L-8 1.Draw a neat and labeled diagram of a solar water heater. Explain its construction and working Construction:

As shown in the above figure, overhead tank is connected with a small tank of solar water heater.Coil shapes copper tube is placed in box, so the area absorbing heat energy can be increased.For more absorption of heat, the outer surface of copper tube is coloured blackOne end of copper tube is connected at the bottom and other is connected at the middle of overhead tank.

Working:Due to the pressure difference between two ends of copper tube, the from overhead tank continuously flows in the tube.Water flows slowly through tube, so it is heated with solar heat.In this way, water in small tank is heated slowly.Hot water is lighter so it remains at upper part of tank and from there it is used with the help of water tap.Q4. Why is the amount of e-waste increasing in the modern era?A4. The amount of e-waste is increasing in the modern era because 1. There is continous population increase 2. Demand of electronic good rises 3. Due to advance technology, people discard old mobile, music system, etc and buy new 4. With change in life style now their are multiple T.V, Mobiles, Music Systems in a houseQ5.What type of remedies can you find to reduce e-waste?A5. The remedies to reduce e-waste are 1.ectronic item should be repaired and used for long time 2. old items can be given back inexchange 3.rome merchants buy back e-waste should be said 4. we can give things which we do not use to some needy person.Q6.What will happen if e-waste is not disposed of properly?A6. In electronic gadgets , circuits ,I.C, I.E integrated circuits soldering metal etc are present they consist of metals like platinium , gold, mercury, tin and chromium .if not disposed properly, they may lead to pollution .so, e-waste should be disposed properlyEX. 8 EXPERIMENT1.DESCRIBE WITH THE HELP OF A DIAGRAM, THE EXPERIMENT OF PREPARATION OF OXYGEN GASAIM: to prepare oxygen gasAPPARATUS AND MATERIALS: test tubes, test tube holder, oxygen gas, candle, an incense stick, potassium permanganatePROCDURE: 1)Take a test tube. 2)Hold it with test tube holder. 3)Put potassium particles in the test tube as shown in the figure. 4)Heat the test tube with the flame of the candle. 5)When potassium permanganate gets heated up in the test tube there will be some cracking sound . 6) After that as shown in the figurehold an incense stick in the test tube and keep it inside the test tube for sometime and observe.OBSERVATION: When we insert burning incense stick in the test tube. it burns more brightly.RESULT: Thus oxygen gas is revolt.CHEMICAL FORMULA INVOLVED IN THE PREPARATION OF OXYGEN :2KmnO4 gives K2MnO4 + MnO2 + O2potassium decomposition potassium manganese oxygenpermanganate mangnate dioxide gasL-4 DESCRIBE THE EXPERIMENT TO FIND THE FOCAL LENGTH OF A CONVEX LENS WITH THE HELP OF A FIGURE:AIM: To find the focal length of a convex lensAPPARTUS REQUIRED: convex lens, stand, white screen, source of lightFIGURE:

PROCEDURE: 1. Take a convex lens 2. keep it on a stand and place the stand on a plane surface 3. Incident light on it with a torch 4. Adjust the screen of drawing paper behind the lens in such a way that a point like image is formed as shown in the figure 5. The location of this point is the focal point of the lens.OBSERVATION: All the rays parallel to the principal axis converge at a point after refraction.CONCLUSION: The distance between the optical centre are focal point of a convex lens is its focal length.