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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1251. |
Melting point |
| Answer» Solution :The TEMPERATURE at which a solid MELTS to BECOME a liquid at the atmosphere pressure is CALLED its melting point. | |
| 1252. |
Melting of ice takes place slowly at higher altitudes. Justify this statement by applying the principle of equilibrium. |
| Answer» Solution :Melting of ice to water is associated with DECREASE in VOLUME. Since the process is associated with decrease in volume, increase in pressure favours the process. THEREFORE, melting of ice takes place at a faster RATE at higher pressure. But at higher altitudes, the pressure being low, the process takes place slowly since the backward process takes place at a faster rate. | |
| 1254. |
Measure 50 mL of any one liquid and transfer it into different containers one by one. Does the volume remains the same? |
| Answer» Solution :If this liquid is TRANSFERRED into DIFFERENT CONTAINERS the volume will REMAIN the same. | |
| 1257. |
Matter is made up of 5 basic elements "The five tatva" which of the following is not among the basic elements? |
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Answer» Plants |
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| 1258. |
Matterdoes not existwithout mass . |
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| 1260. |
Match the physical quantities given in Column A to their SI units given in Column B. |
| Answer» SOLUTION :(a)-(III), (b)-(IV), (c )-(v), (d)-(ii), (E )-(i). | |
| 1263. |
Match the following properiy : |
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| 1267. |
Match the following : {:(,A,,B),((1),K,(a),2.8.1),((2),L,(b),2),((3),M,(c ),2","8.8),((4),"Sodium",(d),18),((5),"Atgon",(e ),8):} |
| Answer» Solution :(1)-b, (2)-E, (3)-d, (4)-a, (5)-C | |
| 1269. |
Match the entries given in column A with appropriate ones in column B |
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| 1270. |
Mass of the following "element" // "compound" is given in grams. Calculate it.s moles and number of "molecules"//"atoms" : 22 g carbon dioxide (CO_(2)) |
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Answer» Solution :Number of moles of 22 G `CO_(2) = ("mass of "CO_(2))/("molecular mass of "CO_(2))` `= (22)/(44)` = 0.5 MOLE Number of MOLECULES in 22 g `CO_(2) = "Number of moles of "CO_(2) XX "Avogadro number"` `= 0.5" mole" xx 6.023 xx 10^(23) "molecules"// "mole"` `= 3.0115 xx 10^(23)` molecules |
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| 1271. |
Mass of the following "element" // "compound" is given in grams. Calculate it.s moles and number of "molecules"//"atoms" : 2 g water (H_(2)O) |
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Answer» Solution :Number of MOLES of 2g `H_(2)O= ("MASS of WATER")/("molecular mass of water")` `=(2)/(18)` `=(1)/(9)` mole Number of molecules in 2 g water `(H_(2)O) = "Number of moles of "H_(2)O xx "Avogadro number"` `=(1)/(9)" mole" xx 6.023 xx 10^(23) "molecules"// "mole"` `~~ 0.6692 xx 10^(23)` molecules `~~ 6.692 xx 10^(22)` molecules |
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| 1272. |
Mass of the following "element" // "compound" is given in grams. Calculate it.s moles and number of "molecules"//"atoms" : 46 g sodium (Na) |
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Answer» Solution :Number of moles of 46 g Na = `("mass of sodium")/("ATOMIC mass of sodium")` = `(46)/(23)` = 2 mole Number of molecules in 46 g sodium (Na) = `"Number of moles of Na" xx "AVOGADRO number"` `= 2" mole" xx 6.023 xx 10^(23) "molecules"// "mole"` = `12.046 xx 10^(23)` molecules `~~ 1.205 xx 10^(24)` molecules |
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| 1273. |
Mass of the following "element" // "compound" is given in grams. Calculate it.s moles and number of "molecules"//"atoms" : 9 g aluminium (Al) |
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Answer» Solution :Number of MOLES of 9 g aluminium = `("mass of aluminium")/("atomic mass of aluminium")` `=(9)/(27)` = `(1)/(3)` mole Number of ATOMS in 9g aluminium (Al) = `"Number of moles of Al" xx "Avogadro number"` `=(1)/(3)" mole" xx 6.023 xx 10^(23) "MOLECULES" // "mole"` `~~ 2.008 xx 10^(23)` molecules |
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| 1274. |
Mass of the following "element" // "compound" is given in grams. Calculate it.s moles and number of "molecules"//"atoms" : 8 g oxygen (O_(2)) |
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Answer» Solution :Number of moles of 8 g OXYGEN = `("mass of oxygen")/("molecular mass of oxygen")` `=(8)/(32)` = 0.25 mole Number of MOLECULES in 8G oxygen `(O_(2)) = "Number of moles of "O_(2) xx "AVOGADRO number"` `= 0.25" mole" xx 6.023 xx 10^(23) "molecules" // "mole"` `= 1.506 xx 10^(23)` molecules |
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| 1275. |
Mass of one molecule of ammonia is |
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Answer» `(1)/(6.022xx 10^(23))` |
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| 1278. |
Make models of the molecules of compunds by using match sticks and clay balls as shown below. |
Answer» SOLUTION :
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| 1279. |
Mainly the mass of an atom depends up on the mass of (protons and neutrons, neutrons and electrons) |
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| 1280. |
Magnesium and Oxygen combine in the ratio of 3:2 by mass to form magnesium oxide. How much oxygen is required to react completely with 12 g of magnesium. |
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Answer» Solution :Magnesium (Mg( and oxygen (O) COMBINE in the RATIO =3:2 to form compound magnesium oxide (Mgo), it follows LAW of constants properties, 3g of Mg combines with =2g of O Therefore 12G of Mg combinaes with `2x12//3=8` of oxygen |
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| 1281. |
LPG is used in the kitchens in our homes in the _____ form. |
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| 1282. |
LPG contains butane and propane in major proportins whereas CNG contains methane as the major componets justify. |
| Answer» Solution :Both butane and PROPANE CANE be liquefied relatively under moderate pressure and liquedfied FORMS radily vapourise under normal conditions .Moreover the calorific value is high and almost equal in both cases.Easy liquafication of these gases permits easy TRANPORT and storage .NATURAL gas is associated with petroleum .It contains methane as major component since it is the hydrocarbons methane volatiliase and escaps out forming a layers of natural gas . | |
| 1283. |
Look at the figure and suggest in which of the vessels A, B,C, or D, the rate of evaporation will be the highest ? Explain. |
| Answer» Solution :Vessel B has the smallest SIZE while vessel D is COVERED. Though vessel A and C are of same size, moving fan will accelerate evaporation in vessel C since it is PLACED directly above it. THEREFORE, the RATE of evaporation will be highest in vessel C. | |
| 1284. |
List three characteristics of particles of matter, giving examples. |
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Answer» SOLUTION :Characteristics of particles of matter are as follows: 1. Particles of matter have SPACE between them. Example: When a small amount of salt is added towater, its mixes without theincrease in volume of water. 2. Particles of matter are moving constinuously. Example: When a crystal of potassium permanganate is added to water, purple COLOUR of potassium permanganate diffuses throughout the water. 3. particles of mater each other. Example: Put a finger across the running water from a TAP.It breaks the flow. Now remove your fingers. The stream of water from the tap regains. |
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| 1285. |
List three characteristics of particles of matter. Describe one example for example for each characteristic to illustrate it. Name the characteristics which are responsible for (a) spreading of smell of scent in a room and (b) water taking the shape of the vessel in which it is poured. |
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Answer» SOLUTION :For the three characteristics of matter and their examples, consult SECTION 1.2. (a) Spreading of smell of scent in a room is because of diffusion of the gases. Scent consists of a number of sweet SMELLING gases or VAPOURS. (B) Water is a liquid and liquids take up the shape of any container in which these are kept. |
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| 1286. |
List three characteristics of particles of matter. Describe one example for each characteristic to illustrate it. Name the characteristics which are responsible for a. Spreading of smell of scent in a room and b. water taking shape of the vessel in which poured. |
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Answer» Solution :Characteristics of matter are as FOLLOWS: 1. The particles of matter have space between them. This is known as intermolecular space. Example: When SMALL amount of sugar is added to water, it gets evenly distributed in water. The particls of one type of matter get into the spaces between particles of the other. 2. THe particles of matter are continuouslay moving. Example: When a crystal of copper sulphate (or potassium permanganat) is dropped in water,the blue colour of copper sulphate (or the purple colour of potassium permanganate) diffuses throughout the volume of water. 3. The particles of matter attract each other. Example: If you keep your finger across theruinning water from a tap it BREAKS. When you remove the finger, the stream of water remains together. The characteristics responsible for: a. diffusion and B. liquid is non RIGID. |
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| 1287. |
List the uses of isotopes . |
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Answer» Solution :The USES of radioactive isotopes are as follows. `{:("Radioactive isotopes","Uses"),("Uranium235","fuel in nuclear reactors"),("COBALT60","TREATMENT of cancer"),("IODINE131","Treatment of goiter"),("Carbon14","Find the AGE of plants and animals"):}` |
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| 1288. |
List the points of differences between homogeneous and heterogeneous mixtures. |
Answer» SOLUTION :
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| 1290. |
List the factors on which evaporation depends? |
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Answer» Solution :1. Surface area exposed to atmosphere. Since evaporation is a surface phenomenon, therefore it increaseswith an INCREASEIN surface area. 2. HUMIDITY :- The air around us cannot hold more than definite amountof water vapour at a giventemperature. If the amount of water in air already high, the rate of evaporation DECREASES. So, evaporation decreases with INCREASE in humidity. 3. Wind Speed : With the increasein wind speed, the particlesof water vapour move away with the wind, decreasing the amount of water vapour in the surrounding. This results in a factor rate of evaporation, So, evaporation with the increase in wind speed. 4. An increase, more number of particles get enough kinetic energyto go into the vapour state. |
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| 1291. |
List the allotopes of phosphorous. |
| Answer» SOLUTION :N/A | |
| 1292. |
List out two applications of equilibrium constant. |
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| 1293. |
List the point of difference between homogenous and heterogenous mixtures? |
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Answer» Solution :HOMOGENEOUS 1. Uniform Composition 2. It has no visible boundaries of separation between constituents. Heterogeneous 1. Non Uniform Composition. 2. It has visible boundries of SEPERATION between its constituents. |
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| 1294. |
List down the differences between Ionic and Covalent compounds |
Answer» SOLUTION :
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| 1295. |
Which observations in scatteing experiment led Rutherford to make the following conclusions: (i) Most of thespace in an atom is empty , (ii) Whole mass of an atom is present in its center. (iii)Nucleus is postively charged. |
| Answer» SOLUTION :For ANSWER , CONSULT SECTION 4.4 | |
| 1296. |
Liquids with low boiling points have greatertendency to evaporate . |
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| 1297. |
Liquids generally lower density as compared to solids. But you must have observed that ice floates on water. Find out why. |
| Answer» Solution :Generally the DENSITY of solid is higher than that of liquid. The STRUCTURE of ice is crystalline with VACANT spaces. DUE to this the denisty of ice is less than that of water. HENCE, ice floats on water. | |
| 1299. |
Liquids generally have lower density as compared to solids but you must have observed that ice floatis on water. Find out/why. |
| Answer» Solution :Ice is formed by the freezing of water. When water FREEZES to form ice, then a number of empty spaces are CREATED in solid ice (which were not present in liquid water) GIVING it a cage-like structure. Due to the presence of some empty spaces, the volume of ice becomes more than an equal mass of water. Because of its greater volume, the DENSITY (mass per unit volume) of ice decreases. And due to its lower density than water, ice floats on water (EVEN though it is a solid). | |
| 1300. |
Liquids generally have lower density as comparedto solids but you must have observed that ice floats on water find out. Why ? |
| Answer» Solution :ICE which is SOLID has vacant SPACES between WATER MOLECULES thus making ice lighter than water. Thus ice floats on water. | |