2599 + Interview Questions in Chemistry in Class 9 Page 7 InterviewSolution

301.	Which of the following phenomena is based on the principle that cooling results due to evaporation ?
Answer» formation of water drops on the surface of cold drink BOTTLE. formation of crystals of ICE on the INNER surface of the lid of an ice cream box in freezer white foggy appearance on the surface of large ice blocks stretching out of tongues by dogs during summer Solution :Doges stretch out their tongues duringsummer because the surface area fo thebodyfrom over-heatingduring summer. Thisis because they cannot sweat LIKE humna being . All otherphenomerna aer DUE to the condenstationof watervapourdue tovery low temperature.

Discussion

302.	What are the general characteristics of these el¬ements.
Answer» ANSWER :

Discussion

303.	Total number of nucleons is the same in the atoms of isobar.
Answer» ANSWER :TRUE

Discussion

304.	What are the different process involved in the dressing of ore ? Explain.
Answer» SOLUTION :N/A

Discussion

305.	What is the mass of 0.5 moles of sucrose (C_(12)H_(22)O_(11))?
Answer» Solution : MOLAR mass of sucrose = `(12 xx 12) + (22 xx 1) + (11 xx 16)` = 144 + 22 + 176 = 342 G Mass = `"molar mass" xx "NUMBER of moles"` `= 342 xx 0.5` = 171 g The mass of 0.5 moles of sucrose is 171 g.

Discussion

306.	Try to segregate the things around you as pure substances and mixtures :(a) distilled water (b) curd(c ) diamond(d) ice cream(e) kerosene(f) cooking oil(g) steel(h) graphite(i) raw rubber(j) vulcanisedrubber(k) solder wire.
Answer» Solution :Pure substances : Distilled WATER, diamond, graphite, raw rubber Mixtures : curd, ice cream, KEROSENE oil, cooking oil, steel, vulcanised rubber, solder wire (ALLOY of LEAD and TIN)

Discussion

307.	which group contains the inner transitin elements?
Answer»

Discussion

308.	There are 11 electrons and 12 neutrons In an atom. Find out the atomic number and mass number.
Answer» ANSWER : ATOMIC number -11 Mass number - 23

Discussion

309.	The solubility of a salt in 100 g of water, at 25^(@)C temperature, is 209 g. Its solubility increases by 10% per 5^(@)C till 50^(@)C temperature, then becomes steady. At 35^(@)C temperature, 26 g of a salt is dissolved in 100 g of water, then this solution will be of ____ type.
Answer» saturated unsaturated suspension colloid Answer :A::D

Discussion

310.	What is the unit of measurenmen of atomic radius ?
Answer» SOLUTION :Piometer (PM) or ANGSTROMS `(A^(@))`.

Discussion

311.	Which of the following salt of calcium is used in the preparation of superphosphate of lime?
Answer» `CA(PO_3)_2` `Ca_3(PO_4)_2` `Ca(HPO_4)_2` `CaSO_4` SOLUTION :N/A

Discussion

312.	Which of the following chemical equation are balanced? H_2+O_2rarrH_2O CO_2+Crarr2CO N_2+H_2rarrNH_3
Answer» ANSWER :`CO_2+Crarr2CO`

Discussion

313.	whichof thefollowingarephysicalchancgesandwhichare chemicalchanges? Burningofcandlewax , Meltingofcandlewax ,meltingof ironfillingandsandburningofwood, Breakinga piece ofchalkburninga piece of paperCuttingapieceof paper
Answer»

Discussion

314.	What is meant by the term chemical formula?
Answer» Solution :The chemical formula of a COMPOUND is the symbolic representation of its composition. It gives the number of ATOMS which are chemically united in a compound. For EXAMPLE, the chemical formula of magnesium chloride is `MgCl_(2)`. In magnesium chloride ONE ATOM of magnesium and two atoms of chlorine are chemically united.

Discussion

315.	Which are the Isotopes of Hydrogen.
Answer» ANSWER :PROTIUM(`_1^1H`) Dueterium (`_1^2H`) TRITIUM (`_1^3H`)

Discussion

316.	Why are the lanthanides and the actinides given a separate position in the modern periodic table?
Answer»

Discussion

317.	When we dissolve salt in sugar which property of matter can be explained?
Answer» PARTICLE SIZE is small Particles of MATTER have interspacing between them Particles are TIGHTLY packed All of the above Answer :B

Discussion

318.	Which of the followingwill show "Tydall Effect"? (a)Salt Solution (b)Milk ( c) CopperSulphateSolution (d)Starch Solution ?
Answer» SOLUTION :Tyndall effect is SHOWN by colloidal solution. Here MILK and starch solution are colloids therefore milk and strach solution will show. Tyndall effect.

Discussion

319.	Who is known as Father of “Nuclear Physics".
Answer» SOLUTION :E. RUTHERFORD

Discussion

320.	Which of the following statements about theunreactive natureof noble gases is (are) true ?
Answer» The INNER SHELLS of noble gas ATOMS are FILLED to capacity . Noble gas atoms cannot give up electrons to or accept electrons from other atoms . The valence shells of the atoms of noblegases are filled to capacity . None of these Answer :B::C

Discussion

321.	Who stated the law of constant proportion ?
Answer» SOLUTION :Joseph Proust STATED the law of CONSTANT proportion.

Discussion

322.	threemixtures A , Band Care obtained by stirringthreedifferentsolidsin watertakeninwatertakeninseparate. Whena beammixture A isallowedtostandforsometime ,thenitsparticles settleat thebottomof thebeaker, whena beamof light is passedthroughmixtureA ina darkroom, thepath oflightbecomesvisible whenobservedfrom thesideof thebeaker . whenmixtureB, However,scatters thebeam of lightjustlikemixtureAtheparticles of mixtureC Donotsettledown on keepingandit alsodoesdoesnot scatternotscattera beamof lightpassingthrough it . what are themixture likeA knownas ? (b)whatare themixtures likeB known as ? ( c)whatare themixtureslike C known as ? (d)namethe phenomenon exhibitedby A and B ,whichoccurson passinga beamof lightthrough them . ( e)nameone mixtureeachwhichis like(i) A (ii) B , and (iii) C.
Answer» Answer :(a)Suspensions(B)COLLOIDS( c)truesolutions(d)tyndall EFFECT( E) (i)chalk - watermixture(ii)soapsolution( c)saltsoltion

Discussion

323.	Which of the following substances is a (are) greenhouse gas(es) ?
Answer» CARBON DIOXIDE Ammonia Methane SULPHUR dioxide ANSWER :A::C

Discussion

324.	What are the differences between ionic, covalent and coordination covalent bond?
Answer» SOLUTION :

Discussion

325.	Which of the followingrepresents a solid liquidmixture ?
Answer» a mixture of SUGAR andsand air air TRAPPED in soil particvles a SOLUTION of common salt in WATER Answer :D

Discussion

326.	We can get the smell of perfume sitting several metres away.
Answer» SOLUTION :Perfume is volatile. It vapourises very fast due to its low boiling point. The vapours diffuses in air EASILY. Therefore we can tet the SMELL of perfume EVE if we are several metres AWAY.

Discussion

327.	The substance X normally exists in a physical state which can flow easily but does not fill its vessel completely. It also turns anhydrous copper sulphate blue. When substance X is cooled excessively, it changes into a substance Y which has a fixed shape as well as a fixed volume. If, however, the substance X is heated strongly, it changes into a substance Z which has neither a fixed shape nor a fixed volume.(a) Name the substances (i) X (ii) Y and (iii) Z.(b) What is the process of conversion of X into Y known as ?(c ) At which temperature X gets converted into Y ?(d) What is the process of conversion of X into Z known as ?(e)At which temperature X gets converted into Z ?
Answer» Answer :(a) (i) Water (ii) Ice (III) STEAM (B) Freezing(c ) `0^(@)C` (d) Boiling (or VAPORISATION)(e)`100^(@)C`

Discussion

328.	What is the relation between equilibrium constant and the stability of reactants ? Justify.
Answer» SOLUTION :ACTIVATION ENERGY

Discussion

329.	Which of the followin oxdies react to form slag in open hearth process ?
Answer» `CAO,CO` `P_2so_5,CaO` `P_2O_5,SiO_2` `CaO,CO_2` SOLUTION :N/A

Discussion

330.	What wouldbe the nature of the mixture when sugar obtained from beetrootand thatobtained from sugarcane are mixed together ?
Answer» SOLUTION :The SUGARS obtained from these two different sources are CHEMICALLY the same. So,the mixture WOULD be a pure substance .

Discussion

331.	What is meant by a substance ?
Answer» SOLUTION :A pure substance consists of a SINGLE type of PARTICLES.

Discussion

332.	Which of the following are pure substances? Ice, Milk, Iron, Hydrochloric acid, Mercury Brick and Water.
Answer» Solution :ICE, IRON, HYDROCHLORIC acid, Mercury and WATER are PURE substances.

Discussion

333.	Which phenomenon occurs during the followin changes? a. Formation of clouds b. Drying of wet clothes c.Melting of wax in the sun d. Size fo the naphthalene ball decreases.
Answer» SOLUTION :a. Condensation, b. EVAPORATION, c. LIQUEFACTION (or fusion) and d. Sublimation.

Discussion

334.	Which seperation techniqueswill you apply for the Seperation of thesmall Pieces ofof the metal inthe engineoil of a car ?
Answer» SOLUTION :FILTRATION

Discussion

335.	What are the merits and the limitations of mendeleev 'speriodic table?
Answer»

Discussion

336.	What is meant by pure substance ?
Answer» SOLUTION :A material that is composed of only ONE type of particles is called pure substance. All the CONSTITUENT particles of a pure substance have same CHEMICAL nature.

Discussion

337.	What is humus? What are its function?
Answer» Solution :Humus is a BLACK material FORMED by the DECOMPOSTION of dead animals and plants . Its gets deposited as a layer over the soil.

Discussion

338.	What are we able to sip hot tea or milk faster from saucer rather than a cup?
Answer» Solution :A LIQUID has a larger surface AREA in a SAUCER than in a cup. Thus it EVAPORATES FASTER and cools faster in a saucer than in a cup. Thus, we are able to sip hot tea or milk faster from a saucer than a cup.

Discussion

339.	What are the advantages of alloys ?
Answer» Solution :Alloys do not get corroded or get corroded to very extent. They are harder and stronger than pure METALS (example : gold is mixed with COPPER and it is harder than pure gold). They have less conductance than pure metals (example : copper is good conductor of heat and ELECTRICITY whereas brass and bronze are not good conductors). Some alloys have lower melting point than pure metals (example : solder is an alloy of lead and TIN which has lower melting point than each of the metals). When metal is alloyed with mercury, it is called amalgam.

Discussion

340.	Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.
Answer» Solution :Both ICE and steam are the physical states of the same substance i.e. water. However, they differ in their nature. Ice on coming in contact with skin (at a highertemperature) ABSORBS energy as latent heat of fusion from the skin and melts. Since energy has been TAKEN up from the body, a cooling sensation is experienced. But when steam comes in contact with the skin (lower temperature) it releases energy which causes SEVERE BURNS on the skin.

Discussion

341.	What is the mass of : 0.2mole of oxygen atoms ?
Answer» Solution :0.2 moles `0.2 xx 16 = 3 * 2 ` G

Discussion

342.	What are the two factors responsible for the liquefaction of gases ?
Answer» SOLUTION :(i) DECREASING temperature (ii) increasing PRESSURE

Discussion

343.	Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.
Answer» Solution :First, water is taken as a SOLVENT in a saucer pan. This water (solvent) is allowed to boil. During heating, milk and tea leaves are ADDED to the solvent as solutes. They form a solution. Then, the solution is poured through a strainer. The insoluble PART of the solution remains on the strainer as residue. SUGAR added to the filtrate, which dissolves in the filtrate. The resulting solution is the required tea.

Discussion

344.	What are instantaneous reactions ? Give two example.
Answer»

Discussion

345.	Which of the following are also considered to bethe states of matter ?(i) Plasma(ii) Platelets(iii)BEC(iv)BHC
Answer» (i) and (II) (ii) and (III) (i) and (iii) (ii) and (IV) ANSWER :C

Discussion

346.	The symbol of oxygen atom is overset(16)underset(8)O (i) What is the name given ot the number of protons in the nucleus of the atom? (ii) What is the name given to the number of protons plus number of neutons in the nucleus of the atom?
Answer» Solution :(i) No of PROTONS in the nucelus of the aotm is KNOWN as atomic number `therefore` Atomic no of OXYGEN (z) =8 (II) No of portons in the nucleus plus no of neutrons in the nucleus is known as MASS number `therefore` Mass no of oxygen (A) =8+8=16

Discussion

347.	Write the possible isomes for the following molecuar formulae. (a) C_4H_8O ( b) C_3H_6O_2 ( c) C_5H_(12)O
Answer» SOLUTION :MOLECULAR formula `C_4H_8O` Possible ismers (i) `UNDERSET("Butanal")(CH_3-CH_2-CH_2-CHO)` (ii) `underset("2-Methyl butanal ")(H_3C-overset(CH_3)overset(\|)"CH"-CHO)`

Discussion

348.	When the solid (Solute) dissolves in a liquid (Solvent), it become a solution.
Answer» ANSWER :1

Discussion

349.	Which of the following are chemical changes ? (i)Decaying of wood (ii) Burning of wood(iii) Growth of wood in a tree (iv) Hammering of a nail on a piece of wood.
Answer» (i) and (II) (ii) and (iv) (iii) and (iv) (i), (ii) (iii). Solution :All the THREE are chemical changes.

Discussion

350.	What are the percentage compositions of hydrogen and oxygen in water (H_(2)O) ? (H =1 , O = 16)
Answer» SOLUTION :Molecular mass of water , `H_(2) O = 2 + 16 = 18` AMU . Percentage of hydrogen `H_(2)O` has two ATOMS of hydrogen So , mass of hydrogen in `H_(2)O = 2` amu . Mass of oxygen = 16 amu `therefore` percentage of hydrogen = `(2)/(18) xx 100 = 11.1` and percentage of oxygen = `(16)/(18) xx 100 = 88.9` .

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following phenomena is based on the principle that cooling results due to evaporation ?

What are the general characteristics of these el¬ements.

Total number of nucleons is the same in the atoms of isobar.

What are the different process involved in the dressing of ore ? Explain.

What is the mass of 0.5 moles of sucrose (C_(12)H_(22)O_(11))?

Try to segregate the things around you as pure substances and mixtures :(a) distilled water (b) curd(c ) diamond(d) ice cream(e) kerosene(f) cooking oil(g) steel(h) graphite(i) raw rubber(j) vulcanisedrubber(k) solder wire.

which group contains the inner transitin elements?

There are 11 electrons and 12 neutrons In an atom. Find out the atomic number and mass number.

The solubility of a salt in 100 g of water, at 25^(@)C temperature, is 209 g. Its solubility increases by 10% per 5^(@)C till 50^(@)C temperature, then becomes steady. At 35^(@)C temperature, 26 g of a salt is dissolved in 100 g of water, then this solution will be of ____ type.

What is the unit of measurenmen of atomic radius ?

Which of the following salt of calcium is used in the preparation of superphosphate of lime?

Which of the following chemical equation are balanced? H_2+O_2rarrH_2O CO_2+Crarr2CO N_2+H_2rarrNH_3

whichof thefollowingarephysicalchancgesandwhichare chemicalchanges? Burningofcandlewax , Meltingofcandlewax ,meltingof ironfillingandsandburningofwood, Breakinga piece ofchalkburninga piece of paperCuttingapieceof paper

What is meant by the term chemical formula?

Which are the Isotopes of Hydrogen.

Why are the lanthanides and the actinides given a separate position in the modern periodic table?

When we dissolve salt in sugar which property of matter can be explained?

Which of the followingwill show "Tydall Effect"? (a)Salt Solution (b)Milk ( c) CopperSulphateSolution (d)Starch Solution ?

Who is known as Father of “Nuclear Physics".

Which of the following statements about theunreactive natureof noble gases is (are) true ?

Who stated the law of constant proportion ?

Which of the following substances is a (are) greenhouse gas(es) ?

What are the differences between ionic, covalent and coordination covalent bond?

Which of the followingrepresents a solid liquidmixture ?

We can get the smell of perfume sitting several metres away.

What is the relation between equilibrium constant and the stability of reactants ? Justify.

Which of the followin oxdies react to form slag in open hearth process ?

What wouldbe the nature of the mixture when sugar obtained from beetrootand thatobtained from sugarcane are mixed together ?

What is meant by a substance ?

Which of the following are pure substances? Ice, Milk, Iron, Hydrochloric acid, Mercury Brick and Water.

Which phenomenon occurs during the followin changes? a. Formation of clouds b. Drying of wet clothes c.Melting of wax in the sun d. Size fo the naphthalene ball decreases.

Which seperation techniqueswill you apply for the Seperation of thesmall Pieces ofof the metal inthe engineoil of a car ?

What are the merits and the limitations of mendeleev 'speriodic table?

What is meant by pure substance ?

What is humus? What are its function?

What are we able to sip hot tea or milk faster from saucer rather than a cup?

What are the advantages of alloys ?

Water as ice has a cooling effect, whereas water as steam may cause severe burns. Explain these observations.

What is the mass of : 0.2mole of oxygen atoms ?

What are the two factors responsible for the liquefaction of gases ?

Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

What are instantaneous reactions ? Give two example.

Which of the following are also considered to bethe states of matter ?(i) Plasma(ii) Platelets(iii)BEC(iv)BHC

The symbol of oxygen atom is overset(16)underset(8)O (i) What is the name given ot the number of protons in the nucleus of the atom? (ii) What is the name given to the number of protons plus number of neutons in the nucleus of the atom?

Write the possible isomes for the following molecuar formulae. (a) C_4H_8O ( b) C_3H_6O_2 ( c) C_5H_(12)O

When the solid (Solute) dissolves in a liquid (Solvent), it become a solution.

Which of the following are chemical changes ? (i)Decaying of wood (ii) Burning of wood(iii) Growth of wood in a tree (iv) Hammering of a nail on a piece of wood.

What are the percentage compositions of hydrogen and oxygen in water (H_(2)O) ? (H =1 , O = 16)