Before to learn or to know surface energy students must know surface tension. To know about the surface tension click here-
Surface energy-
It is given as the work done to increase the unit area of a liquid .Or, It is the energy required to remove a molecule completely from a liquid.Or, The molecules at the surface have extra energy as compared to the molecule in the interior we call this energy as surface energy.
Mathematically it is equal to the surface tension(T) of the liquid.
surface energy
Let we have a liquid surface (film) ABPQ , is of surface tension T .
A force F is applied to the surface so that PQ moves to P’Q’ , by dx
Then work done is given as W= F.dx
As we know Force F= T/2l ( where T is the surface tension ).
Then work done, W= F.dx = (T/2l).dx
As we have defined above surface energy is the work done per unit area ,
So surface energy E = Work done/ change in area = (T/2l).dx/( change in area )
Here change in area = 2l.dx ;
So surface energy E= [(T/2l).dx]/[2l dx] = T ……..eq.
So we can say surface energy of a liquid is equivalent to the surface tension.
( Here questions may be asked as show that surface energy is equivalent to the surface tension.)
[ Note – when a bigger spherical drop of a liquid is broken to form small spherical droplets, the total surface area of the liquid increases . Due to this the surface enegy of the system increases this increase in energy is taken from the system and hence temperature of the system will fall. We can also think it inversely.]
Surface tension– It is the property of a free surface of liquid to get minimum surface area .
The property of a liquid at rest by virtue of which its free surface behaves like a stretched elastic membrane and tries to occupy as small an area as possible called surface tension.
As we know in a liquid , the molecules are not as close to each other as they are in solid . The result in a liquid not having a strong enough cohesive force to have a rigid structure as a solid . But these intermolecular forces are strong enough to give the liquid a definite shape. These molecular force is effective upto certain distance called molecular range . The uppermost layer of the liquid which thickness is equal to the molecular range is called surface film.
To watch the most important derivation of surface tension click on the video link given below-
We can define the surface tension in another way mathematically the surface tension of a liquid is the force of tension acting across a unit length of an imaginary line drawn on the free surface of a liquid at rest . The direction of this force is perpendicular to the line and tangential to the surface.
Surface tension on liquid surface
If F is the force and l is the length of an imaginary line on the surface of liquid then surface tension T is given as
T = F/ l .
But, for a surface film it is given as the
Surface tension ; T = F/2l ;
Unit of surface tension is , Newton/meter or , kgs-2
Dimension of surface tension is ; [ MT-2] or [M L0 T-2]
Note- 1. Temperature of the liquid increases surface tension decreases .
2. The surface tension arises due to the intermolecular cohesive forces .
3. The surface tension doesn’t depend on the area of the surface.
4. Soap or hot water helps in better cleaning of cloths because it reduces the surface tension of water.
After completing the surface tension students must know surface energy.
This assignment contains Important objective questions of mechanical properties of fluid , based on pressure atmospheric pressure , Pascal’s law , buoyancy etc.
It will be beneficial for the students preparing for 11th , NEET / JEE and other examination.
Mechanical properties of fluids
Questions based on fluid pressure , atmospheric pressure, Pascal’s law
1 . Dimension formula of pressure head is – (a) [M0 L0 T0 ] (b) [M L-1 T-2 ] (c) [M0 L1 T-2 ] (d) [M0 L1 T0 ].
Ans-d
2.The two thigh bones each of cross-sectional area 10cm2 supports the upper part of the person of a mass 50 kg . The average pressure sustained by the bones is , (a) 2.5 x 105 N/m2 (b) 4 x 105 N/m2 (c) 5 x 105N/m2 (d) 106 N/m2 .
Ans-a
3.What is the pressure on the swimmer 20m below the surface of water? (a)1atm (b) 2atm (c) 3 atm (d) 4 atm .
Ans-c
4. Water is filled to a height H behind the dame of width w . The resultant force on the dame is ( if d is the density of water), (a) dgwH2 (b) 1/2 dgwH2 (c)2 dgwH2 (d)4 dgwH2.
Ans-b
5. A tank is filled by density d of liquid upto height H . The average pressure on the wall of the container is (a) dgH (b) ½ dgH (c) ¼ dgH (d) 1/8 dgH .
Ans-b
6. Increase in pressure at one point of the enclosed liquid in equilibrium of rest is transmitted equally to all other point of the liquid . This is as per (a) Buoyancy (b) Pascals law (c) conservation of momentum (d) Impulse .
Ans-b
7. By sucking through a straw , a boy can reduce the pressure in his lungs to 750mm of Hg ( density of Hg is 13.6 g/cm3). Using a straw he can drink water from a maximum depth of (a) 13.6 cm (b) 1.36 cm (d) 0.136 cm (d) 10 cm .
Ans-a
8. An open U-tube contains mercury , when 13.6 cm of water is poured into one of the arms of the tube , then the mercury rise in the other arm from its initial level is (a) 1cm (b) 0.5 cm (c) 10cm (d) 5 cm .
Ans-2
9. A cylinder of radius R full of liquid of density d Is rotated about its axis at w rad/sec. The increase in pressure at the centre of the cylinder will be (a) d w2 R2 /2 (b) d w2 R /2 (c) d2 w R /2 (d) d2 w2 R2 /2 .
Ans-a
10. A barometer kept in an elevator reads 76 cm when the accelerator is accelerating upward . The most likely pressure inside the elevator is ( in cm of Hg ) (a) 74 (b) 75 (c) 76 (d) 77 . Ans-d
Questions based on Archimedes principle , Buoyancy (up-thrust )
11. A body floating in water has 1/5th of its volume immersed in water . What fraction of its volume will be immersed , if it floats in liquid of specific gravity 1.2 ? ans- 1/6
12. A cylinder of height 30 cm and radius 7cm is immersed completely in a fluid of density 1.3 x 103 kg/m3 . What is the buoyant force acting on it? G =10m/s2 . ans-60N.
13. A metallic spheres weighs 35g in air and 28.5 g in water. Find its relative density and also find its weight in a liquid of relative density 0.9 . ans- r.d – 5.4 and app-wt-29.15g .
14. A piece of gold weighs 50 g in air and 45g in water. If there is cavity inside the piece of gold , then find its volume ( density of gold is – 19.3 gm/cc) Ans-2.4
15.An alloy of Zn and Cu weighs 16.8 g in air and 14.7 g in water. If relative density of Cu and Zn are 8.9 and 7.1 respectively then determine the amount of Zn and Cu in alloy. Ans- Cu-9.34 Zn-7.45g.
16.An object of mass m is floating in a liquid of density x . if the object is made up of density y , then the apparent weight of the object in the liquid is (a) mg (b) mg(1-x/y) (c) mg (1-y/x) (d) zero. Ans-d
17. A cube of edge length 10 cm is just balanced at the interface of two liquids A and B as shown in fig. if A and B has specific gravity of 0.6 and 0.4 respectively then the mass of the cube is .
(a) 240g (b) 360g (c) 480g (d) 540g . ans-c
18.A boat having some iron pieces is floating in the pond , if iron pieces are thrown in the pond then level of the liquid (a) increases (b) Decreases (c) may increase or decrease (d) remain the same. Ans-b
19.When two liquid of same mass and different densities d1 and d2 mixed together, then the density of the mixture is (a) d1 +d2 (b) d1 +d2 /2 (c) 2d1 d2 / d1 +d2 (d) 2d1 +2d2 . Ans-c
20. When two liquid of same volume and different densities d1 and d2 mixed together, then the density of the mixture is (a) d1 +d2 (b) d1 +d2 /2 (c) 2 d1 d2 / d1 +d2 (d) 2d1 +2d2 . Ans-a
21. if there were no gravity, then which of the following will not be there for the fluid ? (a) viscosity (b)surface tension (c) pressure (d) upward thrust . ans-d
22. An ice cube contains a large air bubble . The cube is floating on the horizontal surface of water contained in a trough. What will happen to the water level when the cube is melts? (a) remain unchanged (b) it will fall (c) it will rise ( d) first it will fall and then rise . ans-a
23. The density of ice is 0.9gm/cm3.What percentage by volume by volume of the block of ice will float outside the water. (a) 10% (b)45% (c)75% (d)90% . ans-a
24. The reading of a spring balance when it is suspended in the air is 6oN . This reading is changed to 40N when it is submersed in water. The specific gravity of the block must be (a) 3 (b) 2 (c) 6 (d)1.5. ans-a
25. The weight of a body in water is one third of its weight in air. The density of the body in gm/cm3 is (a) 0.5 (b) 1.5 (c) 2.5 (d) 3.5 . ans-b
This is the assignment for the practice of objective questions of mechanical properties of solids. Students can consider it as a test paper of the chapter mechanical properties of solids.
1. Breaking stress depends on (a) length of wire (b) Area of cross-section of wire (c) both a and b (d) independent of length and area of cross-section.
2.Which of the following is perfectly plastic? (a) plasticine (b) Quartz fibre (c) steel (d) Rubber.
3. the length of an elastic string is X meter when the tension is 8N and Y m when tension is 10N , what will be the length when tension is 18N . (a) 4X-5Y (b) 5Y-4X (c) 9X-4Y (d) 4Y-9X.
4. When a load of 10kg is hung in the wire, then extension of 2m is produced. Then work done by the restoring force is (a)200J (b) 100J (c) 50J (d) 25J .
5.Substance which can be elastically stretched to large value of strain is called (a) isomers (b) isodiapheres (c) Plastomers (d) Elastomers .
6. A force F doubles the length of the wire of cross-section a . Then the Young’s modulus of the wire is (a) F/a (b) F/3a (c) F/2a (d) F/4a .
7. Breaking stress of a material is 2×108 N/m2, what maximum length of the wire of this material can be taken so that the wire doesn’t break by own weight? ( density of material is 5×103kg/m3) (a) 1km (b)2km (c) 3km (d) 4km.
8.Young modulus of elasticity for a gas is (a) 1 (b) infinity (c) zero (d) none of these .
9. If we added an impurity in the material then its elasticity (a) may change (b) never change (c) remain the same (d) change by a factor of 5 .
10. A structural steel rod has a radius r = 10mm when a force 100 kN is applied . it stretches along its length Y for steel is 2x 1011 N/m2 . aswer the following questions-
(i) what is the stress produced ?
(ii)what is the elongation produced ?
(iii) what is the elastic energy density of the steel rod ?
(iv) elastic potential energy stored in the rod is what?
11.Elasticity of a rigid body is ………..
12. If Young’s modulus is three times of modulus of rigidity. Then the Poisson’s ratio is equal to …………
13. In case of bending of a beam , depression depends on the Young’s modulus Y as proportional to …….
14.The stress strain graph for two materials A and B are shown in fig. (a) Which one has greater Young’s modulus ?(b) which one is strongest material?(c) which is more ductile?(d) which is more brittle?
This assignment contain Important questions of elasticity
( Mechanical properties of solids)
1. what is more elastic water or air?
2. Write copper,steel,rubber and glass in the increasing order of their elasticity.
3.How do modulus of elasticity of a material changes with temperature?
4. The breaking force for a wire is F, what will be the breaking force (i) two parallel wire of same size? (ii) for a single wire of double of thickness? Ans- 2F and 4F
5.What is the modulus of rigidity of a fluid ? Ans-0
6.Define Young’s modulus and modulus of rigidity. Give their expression and units.
7. What is the meant by elastic limit and angle of share?
8. Define Poisson’s ratio, what is its value for perfectly incompressible substance? Ans-0.5
9. Derive an expression for the elastic potential energy of a wire under stress.
10. What is the role of elasticity in everyday life? Give two example.
11. A 4m long aluminium wire whose diameter is 3 mm is used to support a mass of 50 kg. What will be the elongation of the wire? Y for aluminium is 7 x 1011N/m2 ans-3.9mm
12-Calculate the percentage increase in the length of a wire of diameter 2.5mm stretched by a force of 100kg-wt Young’s modulus of the wire is 12.5 x 1010 N/m2.ans-0.16
13.Acable is replaced by anther cable of same length and material but twice the diameter (a) How will this effect the elongation under given load? (b)How does this effect the maximum load it can support without exceeding the elastic limit? Ans-1/4th and D 2 .
14. A material has poisson’s ratio 0.5. If a uniform rod of it suffers a longitudinal strain of 2 x 10-3 . What is the percentage increase in its volume? Ans-0%
15.Two wires of different materials are suspended from a rigid support. They have the same length and diameter carrying the same load at their free ends . (a) Will the stress and strain in each wire be the same? (b) will the extension in both wire will be same? Ans- (a) stress same strain different (b) different.
16.The stress strain graph for two materials A and B are shown in fig.
(a) Which one has greater Young’s modulus ?(b) which one is strongest material?(c) which is more ductile?(d) which is more brittle?
17. A wire stretches a certain amount under a load. If the load and diameter are both increased to three times, find the stretch cause in the wire.
Ans. [3/4l]
18.A metal bar of length L and area of the cross-section A is rigidly clamped between two walls. The young’s modulus of its material is Y and the coefficient of linear expansion is. α. The bar is heated so that its temperature is increased by C. find the force exerted at the ends of. the bar.
Ans. [YA α]
19.A metallic wire is suspended by attaching some weight to it. If is the longitudinal strain and Y is young’s modulus, find the ratio between elastic potential energy and the energy density.
Ans. [volume]
20.A spherical ball contracts in volume by 0.01 when subjected to a normal pressure of 100 atmospheres. What is the bulk modulus of its material in cgs units?
This assignment belongs to the class 10th science chapter-6 , Life process.
All important question belongs to this chapter is given here. After solving this question , students can improve the chapter Life process , and can prepare for board examination.
To get the Important questions of METALS AND NON METALS CLICK HERE-
Life process ( ch-6) (biology)
Multiple choice questions-:
1.Select the incorrect pair.
(a)Respiration-oxidation to food to obtain energy. (b)Nutrition-obtaining and utilising nutrients. (c)Transportation-response to stimuli (d)Excretion-removed to waste by products
2.Which one of the following juice secreted in the human body does not contain any enzyme?
a)Salivary Juice. b)Bile Juice.
c)Gastric Juice. d)Pancreatic Juice.
3.Rings of cartilage present in the throat ensures that,
a)the air passage collapses b)the air passage does not collapse
c)the air is filtered entering the nostrils d)None of these
4.The function of the lymph fluid is to, a) drains excess fluid from extracellular space back into the blood. b) carries digested and absorbed fat from intestine. c) circulates around the body and help in clotting of blood. d )Both (a) and (b).
5.Which of the following are energy foods? (a)Carbohydrates and fats. (b)Proteins and minerals salts. (c)Vitamins and minerals. (d)Water and roughage.
6.In which mode of nutrition an organisms derives its food from the body of another living organisms without killing it? (a) Saprotrophic nutrition. (b)Parasitic nutrition. (c)Holozoic nutrition. (d)Autotrophic nutrition.
7.Roots of the plants absorb water from the soil through the process of,(a)Diffusion. (b)Transpiration. (c)Osmosis. (d)None of these.
8.The site of photosynthesis in the cells of a leaf is, (a)Chloroplast. (b)Mitochondria. (c)Cytoplasm. (d)Protoplasm.
10.Which region of the alimentary canal absorbs the digested food (a)Stomach. (b)Small intestine. (c)Large intestine. (d)Liver.
11.The exit of unabsorbed food material is regulated by,
(a)Liver.
(b)Anus.
(c)Small intestine.
(d)Anal sphincter.
12.Name the substance whose build up in the muscle during vigorous physical exercises may cause cramps?
(a)Ethanol + carbon dioxide +energy.
(b)Lactic acid +energy.
(c)Carbon dioxide+ water+ energy.
(d)Pyruvate.
13.The movement of food in phloem is called:
(a)Transpiration.
(b)Translocation.
(c)Respiration.
(d)Evaporation.
14.The procedure used cleaning the blood of a person by seprating urea from it is called.
(a)Osmosis.
(b)Filtration.
(c)Dialysis.
(d)Double circulation.
Answers.
(1).C
(2).B
(3).B
(4).C
(5).A
(6).B
(7).C
(8).A
(9).A
(10).B
(11).B
(12).C
(13).B
(14).C
To get the Important questions of ACIDS BASES AND SALTS, CLICK HERE-
How to select coaching centre for JEE/NEET Watch the video given below-
Two marks question.–
15.(a)Does the transport of food in plants require living tissue and energy?
(b)Name the components of food that are transported by the living tissues.Our body produces various waste products through different processes. List the waste products with the organs involved in their removal.
16.Differentiate between single and double circulation found in veterbrates.
17.What are the two stages in photosynthesis.Differentiate between aerobic and anaerobic respiration.
18.What is the role of glomerulus in kidney?
Three marks question
19.why is it necessary to separate oxygenated and deoxygenated blood in mammals and birds?
20.Chloroplast are called energy convertors. Explain.
21.What are the functions of lymph in our body.
22.How is haemoglobin associated with respiration explained?
23.How is transpiration pull responsible for upward movement of water?
Five marks questions.
24.(a). In which form are oxygen and carbon dioxide transported in the blood?
(b). What happens to the muscles of the diaphragm, the external intercostal muscles and the position of diaphragm during inspiration and expiration?
(c). Why do the walls of trachea not collapse, when there is less air in it?
25.Shanu told his father that plants exude out a lot of water in the form of vapour through leaves. Define this process .what is its importance ? How do stomata help in this process?
Very important topic for class 10th – lens formula of ray optics watch the video given below-
This assignment provide the important question of class 10 chapter -3 ( Metals and Non-metals)
Before to solve the assignment of this chapter student may solve the assignment of first chapter CLICK HERE-
To solve the assignment of chapter -2, (acids bases and salts ) – CLICK HERE-
Multiple choice Questions
Select odd one from the following elements. a. Bismuth b. Copper c. Zinc d. Arsenic
Which element is present at the top of the reactivity series and is stored in kerosene oil? a. Potassium b. Tin c. Lead d. Gold
The least reactive metal among the following : a. Sodium b. Silver c. Copper d. Lead
A metal less reactive and another metal more reactive than hydrogen are: a. Aluminium and lead b. Iron and magnesium c. Copper and tin d. Copper and mercury
Which of the following metal exists in the liquid state? a. Na b. Ag c. Cr d. Hg
Which of the following non metal is a liquid? a. Carbon b. Sulphur c. Bromine d. Iodine
Which of the following represent the correct order of decreasing reactivity? a. Mg> Al> Zn> Fe b. Mg>Zn> Al> Fe c. Al>Zn> Fe >Mg d. Mg> Fe>Zn>Al
An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water . The element is likely to be a. Ca b. C c. Si d. Fe
Which of the following pairs of reactants will go undergo a displacement reaction? a. Cuso4 +Fe b. ZnSO4+Fe c. MgSO4+Fe d. Ca(SO4)+Fe
Due to its semiconductor properties the non metal used in computer, t.v etc is a. Carbon b. Silicon c. Bromine d. Fluorine
Which of the following metal exists in their native state in nature? I. Cu II. Au III. Zn IV. Ag a. (i) and (ii) b. (ii)and(iii) c. (ii) and (iv) d. (iii) and (iv)
An element A is soft and can be cut with a knife.this is very reactive to air and cannot be kept in open. It reacts vigorously with water. Identify the element from the following a. Mg b. Na c. P d. Ca
Generally non-metal are not conductors of electricity. Which of the following is a good conductor of electricity? a. Diamond b. Graphite c. Sulphur d. Fullerene
What happens when a pellet of sodium is dropped in water? a. It Catches fire and forms oxide. b. It absorbs heat and forms oxide. c. It catches fire and forms hydroxide. d. It absorbs heat and forms and hydroxide.
When calcium oxide is added to water, it completely dissolves in water without forming bubbles. What products are formed in the reaction? a. Ca and H2 b. Ca and H2O2 c. Ca(OH)2 d. CaH2 Two marks questions
Write chemical equations for reaction taking place when a. Potassium with water. b. Steam is passed over hot iron. c. Magnesium is treated with dil.HNO3
Give reason for the following: a. Metals are regarded as electropositive elements. b. When a piece of copper metal is added to a solution of zinc sulphate ,no change takes place but the blue colour sulphates fades away when a piece of zinc is placed in its solution. c. Reaction of Ca with water is less violent .
A student was given Mg , Zn , Fe and Cu metals. He puts each of them in dil. HCL contained in different test tubes . Identify which of them a. Will not displace H2 from dil .HCL. b. Will give H2 with 5% HNO3. c. Will be displaced from its salt solution by all other metals.
Mention the names of the metals for the following: a. Two metals which are alloyed with iron to make stainless steel. b. Two metals which are used to make jewellary .
Give reason of the following: a. School bells are made up of metals. b. Electric wires are made up of copper. Three marks questions
Write three differences between metal and non- metal.
Write two uses of metal and non-metal
Name the following: a. A metal, which is preserved in kerosene. b. A lustrous coloured non metal c. A metal, which can melt while kept on palm . d. A metal, which is poor conductor of heat.
(a) explain the formation of ionic compound CaO with electron dot structure. Atomic number of calcium and oxygen are 20 and 8 respectively. (b) Name the constituent metals of bronze. 25.(a) show the formation of Na2O by the transfer of electrons between the combining atoms (b) Why are ionic compound usually hard. (c) How is it that ionic compounds in the solid state do not conduct electricity but they do so when in molten state? 5 marks Questions
Show on a diagram the transfer of electrons between the atoms in the formation of MgO. Write symbols of cation and anion present in MgO. (b) Name the solvent in which ionic compounds are generally soluble. (c) Why are aqueous solutions of ionic compounds able to conduct electricity?
In what forms metals found in nature? With the help of examples how metal react with oxygen , Water , and dilute acids . Also, write chemical equation for the reactions.
Give reason for the following: a. Ionic compounds have high melting and boiling point. b. Non- metals in general do not displace hydrogen from dilute acids. c. Hydrogen gas is not evolved, when zinc metal reacts with dil. HNO3. d. School bells are made up of metals. e. Sodium hydroxide solution cannot be kept in aluminium containers.
Do you know the harmful effect of Online classes, to see the video click here-
Before to solve these questions of chapter 2 science ‘Acids Bases and Salts’ students have to solve first chapter questions. To get the questions of chapter-1CLICK HERE-
Chemistry Class Xth
Ch-2 Acids, Bases and Salts
Multiple Choice Questions
What is the common name of CaOCl2?(a)Bleaching powder(b)Baking soda(c)Washing soda(d)Lime water
Which one will turn red litmus blue?(a)Vinegar(b)Lemon juice(c)Soft drinks(d)Baking soda solution
10 ml of a solution of NaOH is found to be completely neutralised by 8ml of a given solution of HCL. If we take 20ml of the same solution of NaOH ,the amount of HCL solution required to neutralise it will be:(a)4ml(b)8ml(c)12ml(d)16ml
A solution reacts with zinc granules to give a gas which burns with a pop sound .The solution contains:(a)Mg(OH)2(b)Na2CO3(c)NaCl(d)HCL
The indicator which produces a pink colour in an alkaline solution is:(a)Methyl orange(b)Turmeric paper(c)Phenolphthalein(d)Litmus paper
The discomfort caused by indigestion due to overeating can be cured by taking:(a)Vinegar(b)Lemon juice(c)Baking soda(d)Caustic soda
One of the following is not an organic acid. This is :(a)Ethanoic acid(b)Formic acid(c)Citric acid(d)Carbonic acid
One of the following is a medicine for indigestion. This is:(a)Sodium hydroxide(b)Manganese hydroxide(c)Magnesium hydroxide(d)Potassium hydroxide
Bee sting contains:(a)An acidic liquid(b)A salt solution(c)An alkaline liquid(d)An alcohol
Fresh milk has a PH of 6. When milk changes into curd ,the PH value will :(a)Become 7(b)Become less than 7(c)Become more than 7(d)Remain unchanged
The salt which will give an acidic solution on dissolving in water is:(a)KCL(b)NH4CL(c)Na2CO3(d)CH3COONA
The number of molecules of water of crystallization present in washing soda crystals is:(a)Five(b)Two(c)Ten(d)Seven
Plaster of paris is prepared by heating one of the following to a temperature of 1000C. this is:(a)CaSO3.2H2O(b)CaCl2.2H2O(c)CaCO3.2H2O(d)CaSo4.2H2O
A solution turns red litmus blue, its PH is likely to be(a)1(b)4(c)5(d)10
A solution reacts with crushed eggs-shells to give gas that turns lime -water milky. The solution contains(a)NaCl(b)HCL(c)LiCl(d)KCl
Objective Answer
A
D
D
D
C
C
D
C
A
B
B
C
D
D
D
Derivation of lens formula
Two marks questions
why should curd and sour substances not be kept in brass and copper vessels?
Why do HCl , HNO3 etc. show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Why does an aqueous solution of an acid conduct electricity?
Why does dry HCl gas not change the colour of the dry litmus paper?
While diluting an acid, why it is recommended that the acid should be added to water and not water to the acid?
How is the concentration of hydronium ions affected when a solution of an acid is diluted?
How is the concentration of hydroxide ions affected when excess base is dissolved in a solution of sodium hydroxide?
What will happen if a solution of sodium carbonate is heated? Give the equation of the reaction involved?
Write an equation to show the reaction between plaster of paris and water.
Why does distilled water not conduct electricity , whereas rain water does?
Why do acid not show acidic behaviour in the absence of water?
Plaster of Paris should be stored in a moisture-proof container .explain why ?
What is a neurtralisation reaction ? Give two examples.
Give two important uses of washing soda and baking soda.
A milk adds a very small amount of baking soda to fresh milk.(i)Why does he shift the PH of the fresh milk from 6 to slightly alkaline?(ii)Why does this milk take a long time to set as curd?
3 marks questions
Metal compound A reacts with dilute hydrochloric acid to produce effervescence. The gas evolved extinguishes a burning candle . write a balanced chemical equation for the reaction if one of the compounds formed is calcium chloride.
What will you observe when a small amount of copper oxide is added in a beaker containing dilute hydrochloric acid?
To an aqueous solution of sodium hydroxide a few drops of phenolphthalein were added .What do you observe, to this solution when small amount of dil. HCl was added ? explain your answer.
What is rock salt? Why is it brown in colour?
Why is washing soda also called basic salt? what are its uses?
How do metal carbonates and metal hydrogen carbonate react with acids? Give their chemical equations.
Write chemical name, chemical formula of bleaching powder. Write its chemical reaction and also write its two uses.
Write chemical name, chemical formula of caustic soda. write its chemical reaction and two uses.
Five solutions A, B, C, D and E when tested with universal indicator showed pH as,(a)Neutral (b)Strongly alkaline (c)Strongly acidic (d)Weakly acidic(e)Weakly alkaline. Arrange the pH in increasing order of hydrogen ion concentration.
What are olfactory indicators? Write an example, also Write the name of two natural indicator.
5 marks questions
What is plaster of Paris? Write its chemical name and chemical formula. Also write the chemical reaction and its two uses.
Write balanced chemical equations for the following: (a)Chlorine gas is passed through dry slaked lime. (b)Bleaching powder is kept in open air.(c)Sodium bicarbonate is reacts with dilute hydrochloric acid.(d)Electricity is passed through brine.(e)Formation of baking soda from sodium chloride.
In Maths, integration is a method of adding or summing up the parts to find the whole. It is a reverse process of differentiation, where we reduce the functions into parts. This method is used to find the summation under a vast scale. Calculation of small addition problems is an easy task which we can do manually or by using calculators as well.
But for big addition problems, where the limits could reach to even infinity, integration methods are used. Integration and differentiation both are important parts of calculus. The concept level of these topics is very high. Hence, it is introduced to us at higher secondary classes and then in engineering or higher education.
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We can say, integration is the calculation of an integral. Integrals in mathematics are used to find many useful quantities such as areas, volumes, displacement, etc. When we speak about integrals, it is related to usually definite integrals. The indefinite integrals are used for anti-derivatives. Integration is one of the two major calculus topics in Mathematics, apart from differentiation(which measure the rate of change of any function with respect to its variables). It’s a vast topic which is discussed at higher level classes like in Class 11 and 12
To download the important questions of indefinite integration click below.
Which of the following does not involve in a chemical reaction?(a)Digestion of food in our body. (b)Process of respiration.(c)Burning of candle wax when heated.(d)Melting of candle wax when heated.
What happens when dilute Hydrochloric acid is added to iron fillings?(a)Hydrogen gas and iron chloride are produced.(b)Chlorine gas and iron hydroxide are produced.(c)No reaction takes place.(d)Iron salt and water are produced.
Which of the following reaction is an endothermic reaction?(a)Burning of coal.(b)Decomposition of vegetable matter into compost.(c)Process of respiration.(d)Decomposition of calcium carbonate to form quick lime and carbon dioxide.
A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation of the observation?(a)KMnO4 is an oxidizing agent, it oxidizes FeSo4.(b)FeSO4 acts as an oxidizing agent and oxidizes KMnO4.(c)The colour disappears due to dilution; no reaction is involved.(d)Kmo4 is an unstable compound and decompose in presence of FeSO4 to a colourless compound.
The chemical reaction between quick lime and water is characterised by:(a)Evolution of hydrogen gas.(b)Formation of slaked lime precipitate.(c)Change in temperature of mixture.(d)Change in colour of the product.
One of the following is an exothermic reaction, this is: (a)Electrolysis of water.(b)Conversion of limestone into quicklime.(c)Process of respiration.(d)Process if photosynthesis.
The chemical equations are balanced to satisfy one of the following laws in a chemical reactions. This law is known as:(a)Law of conservation of momentum.(b)Law of conservation of mass.(c)Law of conservation of motion.(d)Law of conservation of magnetism.
The removal of oxygen from a substance is called:(a)Oxidation.(b)Corrosion(c)Reduction(d)Rancidity.
The chemical reaction involved in the corrosion of iron metal is that of :(a)Oxidation as well as displacement.(b)Reduction as well as combination.(c)Oxidation as well as combination.(d)Reduction as well as displacement.
In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of :(a)Cl2(b)N2 (c)H2(d)O2
Which if the following can be decomposed by the decomposition of light?(a)Nacl (b) Kcl (c)Agcl (d)Cucl
A white precipitate can be obtained by adding dilute sulphuric acid to:(a)CuSO4 solution(b)NaCl solution(c)BaCl2 solution(d)Na2SO4 solution
The term used to indicate the development of unpleasant smell and taste in fat and oil containing foods due to aerial oxidation is :(a)Acidity(b)Radioactivity(c)Rabidity(d)Rancidity
When ferrous sulphate is heated strongly it undergoes decomposition to form ferric oxide as a main product accompanied by a change in colour form:(a)Blue to green(b)Green to blue(c)Green to brown(d)Green to yellow
When carbon dioxide is passed through lime water.(a)Calcium hydroxide is formed(b)White precipitate of CaO is formed(c)Lime water turns milky(d)Colour of lime water disappears
Why magnesium ribbon is cleaned before burning in air?
Write two characteristics of chemical reaction?
What is a balanced chemical reaction .why a chemical reaction should be balanced?
Why is respiration considered as an exothermic process?
What is a rusting of iron? Write an example.
What is a redox reaction?
Define combination reaction with an example?
3 Marks questions
1. In a container, solid calcium oxide was taken and water was added slowly to it.
2. State the two observations made in the experiment.
3. Write the name and the chemical formula of the product formed.
4. Why are decomposition reaction called the opposite of combination reactions?
5. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
6. A shiny brown coloured element X on heating in air becomes black in colour. Name the element X and the black coloured compound formed.
5 marks questions
1. Consider the chemical equation given below and answer the questions that follow: ZnO + C = Zn + CO . (a) Name the substance which is getting oxidized. (b)Name the substance which is getting reduced. (c)Name the oxidising agent. (d)Name the reducing agent. (e)What type of reaction does this equation represents.
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