Basic Concepts

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Basic concepts No Questions Help 1 The percentage of oxygen in NaOH is ( ) 40 ( ) 10 ( ) 8 ( ) 60 Single Answer 2 What quantity of limestone (CaCO3) on heating will give 56 kg of CaO ( ) 1000 kg ( ) 44 kg ( ) 100 kg ( ) 56 kg Single Answer 3 Which of the following has least mass ( ) 3 x 10^23 atoms of C ( ) 7.0 g of Ag ( ) 1 mole of S ( ) 2 gram atom of nitrogen Single Answer 4 1 mole of CH4 contains Single Answer

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Multiple Choice Questions on Basic concepts in Chemistry

Transcript of Basic Concepts

Basic concepts

NoQuestionsHelp

1The percentage of oxygen in NaOH is( )40

( )10

( )8

( )60

Single Answer

2What quantity of limestone (CaCO3) on heating will give 56 kg of CaO( )1000 kg

( )44 kg

( )100 kg

( )56 kg

Single Answer

3Which of the following has least mass( )3 x 10^23 atoms of C

( )7.0 g of Ag

( )1 mole of S

( )2 gram atom of nitrogen

Single Answer

41 mole of CH4 contains ( )3.0 g of carbon

( )1.81 x 10^23 molecules of CH4

( )6.02 x 10^23 atoms of H

( )4 g-atom of hydrogen

Single Answer

5How many moles of Helium gas occupy 22.4 L at 0 degree Celcius and 1 atm pressure( )0.90

( )1.0

( )0.11

( )1.11

Single Answer

6The number of atoms contained in 11.2 L of SO2 at S.T.P. are( )3/2 x 6.02 x 10^23

( )2 x 6.02 x 10^23

( )6.02 x 10^23

( )4 x 6.02 x 10^23

Single Answer

7The number of oxygen atoms in 4.4 g of CO2 is approximately( )6 x 10^23

( )1.2 x 10^23

( )12 x 10^23

( )6 x 10^23

Single Answer

8The total number of protons in 10 g of calcium carbonate is (No=6.023 x 10^23)( )1.5057 x 10^24

( )2.0478 x 10^24

( )3.0115 x 10^24

( )4.0956 x 10^24

Single Answer

92 g of oxygen contains number of atoms equal to that in( )7 g of nitrogen

( )0.5 g of hydrogen

( )2.3 g of sodium

( )4 g of sulphur

Single Answer

10If N(A) is avogadro's number, then number of valence electrons in 4.2 g of nitride ions N^3- is( )4.2 N(A)

( )1.6 N(A)

( )3.2 N(A)

( )2.4 N(A)

Single Answer

11The hydrogen phosphate of certain metal has formula MHPO4. The formula of metal chloride would be( )M2Cl2

( )MCl3

( )MCl2

( )MCl

Single Answer

12The number of atoms in 4.25 g of NH3 is approximately( )1 x 10^23

( )1.5 x 10^23

( )2 x 10^23

( )6 x 10^23

Single Answer

13The maximum amount of BaSO4 precipitate on mixing BaCl2 (0.5 M) with H2SO4 (1 M) will correspond to( )1.0 M

( )1.5 M

( )2.0 M

( )0.5 M

Single Answer

14The largest no. of molecules is in( )54 g of N2O5

( )46 g of CH3OH

( )28 g of CO2

( )34 g of water

Single Answer

15Assuming full decomposition the volume of CO2 released at STP on heating 9.85 g of BaCO3 (At. Mass Ba=197) will be( )1.12 L

( )0.84 L

( )4.06 L

( )0.24 L

Single Answer

16In a mole of water vapours ar STP the volume actually occupied or taken by the molecules (i.e. avogadro's no. x volume of one molecule) is( )Zero

( )1% to 2% of 22.4 L

( )About 10% of the volume of container

( )Less than 1% of 22.4 L

Single Answer

17Vapour density of a gas is 22. What is its molecular mass( )22

( )44

( )11

( )33

Single Answer

181.5 mol of O2 combine with Mg to form oxide MgO. The mass of Mg( at.mass 24) that has combined is( )72 g

( )36 g

( )24 g

( )48 g

Single Answer

19The volume of water to be added to 100 cm3 of 0.5 N H2SO4 to get concentrated is( )500 cm3

( )450 cm3

( )100 cm3

( )400 cm3

Single Answer

20Among the following pairs, the one which illustrates the law of multiple proportion is( )CuO, Cu2O

( )H2S, SO2

( )NH3, HCl

( )CS2, FeSO4

Single Answer

21The set of numerical coefficients that balances the chemical equation K2CrO4 + HCl------->K2Cr2O7 + KCl + H2O( )2,2,1,2,1

( )1,1,2,2,1

( )2,1,1,2,1

( )2,2,1,1,1

Single Answer

22The prefix 10^18 is( )Exa

( )Kilo

( )Giga

( )Nano

Single Answer

23Difference in density is the basis of( )Molecular attraction

( )Ultrafiltration

( )Gravity separation

( )Molecular sieving

Single Answer

24Irrespective of the source, pure sample of water always yields 88.89 % mass of oxygen and 11.11% mass of hydrogen. This is explained by the law of( )Multiple proportions

( )Definite proportions

( )Constant volume

( )Conservation of mass

Single Answer

25The weight of one molecule of a compound C60H122 is( )1.3 x 10^-20 g

( )3.72 x 10^23 g

( )5.01 x 10^-21 g

( )1.4 x 10^-21 g

Single Answer

26Number of atoms in 558.5 g of Fe (At.mass of Fe=55.85 g/mol) is( )Twice that in 60 g carbon

( )Half that in 8 g of He

( )558.5 x 6.022 x 10^23

( )6.022 x 10^22

Single Answer

27To differentiate between C-12, C-13 and C-14, the instrument that you would use is( )Ultravoilet spectrometer

( )Mass spectrometer

( )Infra-red spectrometer

( )Atomic absorption spectrometer

Single Answer

280.56 g of a gas occupies 280 cm3 at N.T.P, then its molecular mass is( )4.8

( )22.4

( )2

( )44.8

Single Answer

29Which one of the following is ambiguous( )A mole of potassium ions

( )A mole of electrons

( )A mole of sodium atoms

( )A mole of hydrogen

Single Answer

30X litres of carbon monoxide is present at S.T.P. It is completely oxidized to CO2. The volume of CO2 formed is 11.207 L at S.T.P. What is the value of X in litres( )22.414 L

( )11.207 L

( )5.6035 L

( )44.828 L

Single Answer

310.078 g of a hydrocarbon occupy 22.414 mL of volume at S.T.P. The empirical formula of the hydrocarbon is CH. The molecular formula of hydrocarbon is( )C6H6

( )C8H8

( )C4H4

( )C2H2

Single Answer

32In Haber process 30 L of dihydrogen and 30 L of dinitrogen were taken for reaction which yielded only 50% of the expected product. What will be the composition of gaseous mixture under the aforesaid conditions in the end( )20 L of ammonia, 20 L of nitrogen, 20 L of hydrogen

( )20 L of ammonia, 25 L of nitrogen, 15 L of hydrogen

( )10 L of ammonia, 25 L of nutrogen, 15 L of hydrogen

( )20 L of ammonia, 10 L of nitrogen, 30 L of hydrogen

Single Answer

33What volume of hydrogen gas at 273 K and 1 atm pressure will be consumed in obtaining 21.6 g of elemental boron (at.mass=10.8) from the reduction of boron trichloride by hydrogen( )67.2 L

( )89.6 L

( )22.4 L

( )44.8 L

Single Answer

34The equivalent weight of a certain trivalent element is 20. Molecular weight of its oxide is( )168

( )152

( )56

( )68

Single Answer

35There are two isotopes of an element with atomic mass z. Heavier one has atomic mass z+2 and lighter one has z-1, then abundance of lighter one is( )33.3%

( )96.7%

( )66.6%

( )6.67%

Single Answer

36In an acidic medium dichromate ion oxidizes ferrous ion to ferric ion. If the gram molecular mass of potassium dichromate is 294 g, its gram equivalent mass is ______grams( )49

( )294

( )24.5

( )127

Single Answer

37The empirical formula of a compound is CH2O and its molecular mass is 120. The molecular formula of the compound is( )C4H8O4

( )CH2O

( )C2H4O2

( )C3H6O3

Single Answer

382g of aluminium is treated, separately with excess of dilute H2SO4 and excess of NaOH the ratio of volumes of hydrogen evolved is( )1:2

( )1:1

( )2:1

( )2:3

Single Answer

39The numerical value of N/n (where N is the number of molecules in a given sample of gas and n is the number of moles of the gas) is( )8.314

( )6.02 x 10^23

( )1.66 x 10^-19

( )1.62 x 10^-24

Single Answer

40A sample of phosphorus trichloride (PCl3) contains 1.4 moles of the subtance. How many atoms are there in the sample?( )5.6

( )8.431 x 10^23

( )4

( )3.372 x 10^24

Single Answer

41A gaseous mixture contains 50% helium and 50% methane by volume. What is the percent by weight of methane in the mixture?( )80.03%

( )50%

( )10.05%

( )19.97%

Single Answer

42How will you separate a mixture of two gases( )Osmosis

( )Chromatography

( )Fractional distillation technique

( )Graham's law of diffusion technique

Single Answer

43What is the net charge on ferous ion( )+2

( )+5

( )+4

( )+3

Single Answer

446.0 x 10^20 molecules of urea are present in 100 mL of its solution. The concentration of urea solution is( )0.02 M

( )0.1 M

( )0.001 M

( )0.01 M

Single Answer

45Volume of 0.1 M K2Cr2O7 required to oxidise 35 mL of 0.5 M FeSO4 solution is ( )17.5 mL

( )175 mL

( )145 mL

( )29.2 mL

Single Answer

46For decolourizing 1 mole of KMnO4, in acidic medium the moles of H2O2 required is( )5/2

( )7/2

( )3/2

( )1/22KMnO4 + 5H2O2 + 3H2SO4 ---> 2MnSO4 + 5O2 + K2SO4 + 8H2O

Single Answer

474 g of copper was dissolved in conc.Nitric acid. The copper nitrate so obtained on strong heating gave 5 g of its oxide. The equivalent weight of copper is( )23

( )32

( )20

( )12

Single Answer

48In alkaline medium ClO2 oxidises H2O2 to O2 and itself gets reduced to Cl-. How many moles of H2O2 are oxidized by 1 mole ClO2( )1.5

( )1.0

( )3.5

( )2.5

Single Answer

49100 g of CaCO3 is treated with 1 L of 1 N HCl. What would be the weight of CO2 liberated after the completion of the raction( )33 g

( )11 g

( )22 g

( )5.5 g

Single Answer

50If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the realtive atomic mass unit, the mass of one mole of substance will( )Increase two fold

( )Decrease twice

( )Be a function of the molecular mass of substance

( )Remains unchanged

Single Answer

51If 30 mL of H2 and 20 mL of O2 reacts to form water, what is left at the end of the reaction( )10 mL of O2

( )10 mL of H2

( )5 mL of O2

( )5 mL of H2

Single Answer

52An alkaloid contains 17.28 % of nitrogen and its molecular mass is 162. The number of nitrogen atoms present in one molecule of alkaloid is( )Three

( )Two

( )Four

( )Five

Single Answer

53'x' grams of calcium carbonate was completely burnt in air. The weight of the solid residue formed is 28 g. What is the value of 'x' in grams( )150

( )50

( )44

( )200

Single Answer

54What is the concentration of nitrate ions, if equal volumes of 0.1 M AgNO3 and 0.1 M NaCl are mixed together( )0.1 M

( )0.25 M

( )0.2 M

( )0.05 M

Single Answer

55A solution of 10 mL of M/10 FeSO4 was titrated with KMnO4 solution in acidic medium, the amount of KMnO4 used will be( )10 mL of 0.5 M

( )5 mL of 0.1 M

( )10 mL of 0.1 M

( )10 mL of 0.02 M

Single Answer

56The volume in litres of CO2 liberated at STP when 10 grams of 90% pure limestone is heated completely is( )2.24

( )20.16

( )22.4

( )2.016

Single Answer

57An organic compound contains 49.3% carbon, 6.84% hydrogen and its vapour density is 73. Molecular formula of compound is( )C4H10O2

( )C3H5O2

( )C3H10O2

( )C6H10O4

Single Answer

58"A piece of iron was placed in a china dish. After a month Dr.Khan found it rusted. He thought that air must be responsible for rusting of iron." This statement is consist of( )Observation and conclusion

( )Observation and hypothesis

( )Idea and data

( )Idea and hypothesis

Single Answer

59During chemical analysis of a compound containing carbon, hydrogen and oxygen, H2O produced is absorbed by( )NaOH

( )Mg(OH)2

( )Mg(ClO4)2

( )CaCO3

Single Answer

60Which of the following represents 1 mol of the substance( )6.022 x 10^24 molecules of NH3

( )4 g of helium

( )40 g calcium chloride

( )6.022 x 10^-24 molecules of CO2

Single Answer

61Urea (NH2)2CO is used as fertilizer. If 2 moles of urea are present in a container than mass of nitrogen in the compound will be( )14 g

( )28 g

( )56 g

( )42 g

Single Answer

628 g of methane contains( )4 x 6.022 x 10^23 hydrogen atoms

( )4 hydrogen atoms

( )6.022 x 10^23 carbon atoms

( )0.5 mol of carbon atoms

Single Answer

63A beaker has 180 g of water in it. Number of moles of oxygen atoms in it will be( )18

( )10

( )180

( )20

Single Answer

6423.5 g of N2 contain as much atoms as in( )23.5 g of Cl2

( )23.5 g of H2

( )23.5 g of CO

( )23.5 g of O2

Single Answer

65Sample containing maximum number of atoms among the following is( )6 g of He

( )28 g N2

( )4 g H2

( )48 of O2

Single Answer

66An unknown compound was analyzed. The result relealed that it contain 80% carbon and 20% hydrogen. On the basis of the available data, empirical formula of the compound must be( )CH

( )CH2

( )C2H5

( )CH3

Single Answer

67All of the following compounds can be analyzed by combustion analysis except( )C12H22O11

( )C6H6

( )H2O2

( )C2H2

Single Answer

68If a piece of 4 mol of lithium is dropped in 72 g of water in a container then( )2 mol of water is left unreacted

( )2.5 mol of lithium is left unreacted

( )2 mol of lithium is left unreacted

( )None of the reactants is left unreacted

Single Answer

69If sulphur is in excess then production of 2 mol of ferrous sulfide requires( )4 mol of iron

( )56 g of iron

( )2 mol of iron

( )28 g of iron

Single Answer

70If theoritical and percentage yields of a product are 50 g and 90 g respectively, then actual yield of the product will be( )70 g

( )80 g

( )45 g

( )35 g

Single Answer

71All of the following may not be the average atomic masses except( )30.03

( )32

( )12

( )2

Single Answer

72Dr.Khan has discovered two isotopes of an element with atomic number 119. The relative abundance of isotopes 119Uue300 and 119Uee305 is 70% and 30% respectively. The average atomic mass of Uue is( )301.5 a.m.u

( )303.5 a.m.u

( )302.5 a.m.u

( )304.5 a.m.u

Single Answer

73DDT is widely used as an isecticide. Its molar mass is 354.5 g/mol. When DDT was analyzed by a chemist he found that it contains 47.4% carbon. How many carbon atoms are there in each DDT molecule( )10

( )14

( )12

( )16

Single Answer

74The mass of 2 moles of sodium hydroxide will be( )20 g

( )2 g

( )80 g

( )40 g

Single Answer

75A compound contains two elements X and Y. Percentage of X is 20% (At.wt=40) and that of Y is 80% (At.wt=80). The empirical formula of the compound is( )XY2

( )X3Y

( )XY

( )X2Y

Single Answer

76A piece of paper is burnt in air, the gas produced is passed through distilled water. The pH of water solution will be( )1

( )2.1

( )7

( )6.7

Single Answer

77Ozone filters the cosmic rays if sunlight. How many oxygen atoms are there in 0.2 mol of ozone (O3 molar mass=48.0g/mol)( )6.02 x 10^22

( )3.61 x 10^23

( )6.02 x 10^23

( )6 x 10^23

Single Answer

78FeSO4.xH2O loses its water of crystallization upon heating. In an experiment 2.1 mole of water is obtained by heating 0.3 mole of the hydrated salt. Chemical formula of FeSO4.xH2O is( )FeSO4.6H2O

( )FeSO4.7H2O

( )FeSO4.8H2O

( )FeSO4.5H2O

Single Answer

79Tobacco contains a poisonous alkaloid called Nicotine. The molecular formula of nicotine is C10H14N2 (molar mass=162.23 g). The mass percentage of nitrogen in nicotine is?( )17.3%

( )12.4%

( )4.32%

( )8.23%

Single Answer

80A sample of an ionic compound contains 2.82 g Na, 4.35 g Cl and 7.83 g O. The empirical formula of this compound is( )NaClO4

( )NaClO2

( )NaClO3

( )NaClO

Single Answer

81Verbal or mathematical relationship between phenomenon is called( )Observation

( )Law

( )Conclusion

( )Data

Single Answer

82The statement that "the composition of a particular compound always remains constant" is a( )Law

( )Hypothesis

( )Fact

( )Theory

Single Answer

83"Solid potassium bromide was mixed with solid silver nitrate". The expectation of a chemist will be( )Silver bromide will be produced

( )Potassium nitrate and silver bromide will be produced

( )No chemical reaction will occur

( )Potassium nitrate will be produced

Single Answer

84All of the following are pure substances except( )Diamond

( )Alumina

( )Graphite

( )Sea water

Single Answer

85All of the following are not pure substances except( )Hard water

( )Tap water

( )Heavy water

( )Rain water

Single Answer

86All of the following are not molecule except( )H2O2

( )CaCl2

( )Na2O2

( )Al(NO3)3

Single Answer

87Which of the following is not related to a.m.u?( )Kilogram

( )Microgram

( )Gram/lit

( )Gram

Single Answer

88Copper(II) oxide is mixed with organic compound during combustion analysis. The purpose is( )To carry out complete combustion

( )To reduce the economy of the process

( )To reduce the time for completion of the reaction

( )All of the above

Single Answer

89The following statement contained in a student's laboratory report is a conclusion.( )The gas is chlorine

( )Color of the gas is greenish yellow

( )Oxide of the gas is strongly acidic

( )A gas is liberated

Single Answer

90One a.m.u is equal to( )1.661 x 10^-24 kg

( )1.661 x 10^-24 mg

( )1.661 x 10^-27 kg

( )1.661 x 10^-27 g

Single Answer

91Objects of the size of an atom can be observed in( )An x-ray spectrum

( )Atomic absorption spectrum

( )An electron microscope

( )A visible spectrum

Single Answer

92Which one of the following statements is not correct( )He is a molecule of helium

( )S8 is a molecule of sulphur

( )O3 is a molecule of oxygen

( )A molecule is the smallest particle of an element which can exist independently

Single Answer

93A molecule of hemoglobin is made up of nearly( )10,000 atoms

( )1500 atoms

( )2500 atoms

( )50,000 atoms

Single Answer

94Which of the following statement is correct. For a chemical reaction to occur molecules of substances must( )Collide with high frequency

( )Collide with energy more than activation energy

( )Collide with each other

( )Collide with energy less than activation enegy

Single Answer

95Al^3+ is a symbol for aluminium( )Atom

( )Cation

( )Anion

( )Ion

Single Answer

96Cr2O7^2- is a( )A complex anion

( )Double salt

( )A carbocation

( )A complex ion

Single Answer

97A molecular ion is formed by( )Passing electric current through molten salt

( )Dissolving a salt in dilute acid

( )Passing electricity through aqeous solutions

( )Passing a high energy electron beam through gaseous molecule

Single Answer

98Mass spectrometer mesures( )Exact mass of an element

( )Average mass of an element

( )The number of elements present in a molecule

( )M/e value of a positive ion

Single Answer

99Percentage of H is highest in( )NH3

( )CH4

( )C6H12O6

( )H2SO4

Single Answer

100Ascorbic acid contains 40.92% carbon, 4.58 % hydrogen and 54.5 % oxygen. The empirical formula is( )C2H4O3

( )C2H3O1

( )C3H4O3

( )C3H5O4

Single Answer

101The relative abundance of Pb isotopes is 1.5% Pb 204, 23.6% Pb 206, 22.6% Pb 207, 52.3% Pb 208. The relative atomic mass of Pb is( )206.94

( )207.94

( )207.24

( )208.24

Single Answer

102The pressure of vapours when sent to the ionization chamber in mass spectrometer is( )10^-6 to 10^-7 torr

( )10^-5 to 10^-6 torr

( )10^-3 to 10^-4 torr

( )10^-7 to 10^-8 torr

Single Answer

103The relative abundance of the ions with a definite m/e value is measured by( )Quantity of fast moving electrons

( )High pressure of vapours

( )Strength of electric current measured

( )Electron gas

Single Answer

104Which of the following statements is not true( )Isotopes with even atomic masses are comparatively abundant

( )Isotopes with even atomic masses and odd atomic numbers are comparitively abundant

( )Isotopes with even atomic masses and even atomic number are comparatively abundant

( )Isotopes with odd atomic masses are comparatively abundant

Single Answer

105Which of the following compounds contains the highest percentage by mass of nitrogen( )Ammonium carbonate, (NH4)2CO3

( )Ammonia, NH3

( )Hydrazine, N2H4

( )Ammonium carbamate, NH2CO2NH4

Single Answer

106Which one of the following compounds does not have the empirical formula CH2O( )Glucose, C6H12O6

( )Mthanal, HCHO

( )Ethanoic acid, CH3CO2H

( )Ethanol, CH3CH2OH

Single Answer

107The empirical formula of a liquid compound is known to be C2H4O. What other information is needed to work out its molecular formula( )The relative molecular mass of the compound

( )The volume occupied by one mole of the compound

( )The density of the compound

( )The percentage composition of the compound

Single Answer

108H2O produced during combustion of an organic compound is absorbed in( )Mg(ClO4)2

( )50% KOH

( )Conc.H2SO4

( )Al2O3

Single Answer

109The percentage of which element in the organic compound is determined by the difference method( )Carbon

( )Hydrogen

( )Nitrogen

( )Oxygen

Single Answer

110A compound contains one atom of oxygen and % of O 34.78, then molecular mass of the compound is( )46

( )78

( )180

( )110

Single Answer

111A compound having empirical formula C3H3O and its molecular mass is 110.02. Its molecular formula is( )C6H6O2

( )C9H9O3

( )C3H3O

( )C3H6O2

Single Answer

112Which has greater number of moles( )6.02 x 10^20 atoms of magnesium

( )20 cm3 0.1 mole per dm3 of NaOH

( )0.1 g sodium

( )12.2 dm3 of nitrogen at standard, temperature and pressure [Ar Na=23, Mg=24, O=16]

Single Answer

113One mole of ethanol and one mole of ethane have an equal( )Number of molecules

( )Number of electrons

( )Mass

( )Number of atoms

Single Answer

114A compound X contains 50% sulphur and 50% oxygen by mass. What is the empirical (simplest) formula of compound X( )SO

( )SO2

( )SO3

( )SO4

Single Answer

115Two different hydrocarbon each contain the same percentage by mass of hydrogen. It follows that they have the same( )Relative molecular mass

( )Number of atoms in a molecules

( )Number of isomers

( )Empirical formula

Single Answer

116A compound contains 75% carbon and 25% hydrogen, by mass. What is the molecular formula of the compound( )C3H8

( )CH4

( )C2H4

( )C2H6

Single Answer

117How many moles of hydrogen atoms does 3.2 g of methane, CH4 contain( )0.4

( )0.8

( )0.02

( )0.2

Single Answer

118A balloon contains 0.02 g of He gas, it contains He molecules( )3.01 x 10^22

( )6.02 x 10^23

( )6.02 x 10^21

( )3.01 x 10^21

Single Answer

119One mole of C2H5OH contains the number of H-atoms( )6.02 x 10^23

( )6.02 x 10^24

( )3.61 x 10^24

( )1.81 x 10^24

Single Answer

120A ring contains 3 grams diamond. The number of C-atoms which a ring contains is( )3.01 x 10^24

( )3.01 x 10^23

( )1.5 x 10^23

( )6.02 x 10^24

Single Answer

121When nitrogen is 5.6 grams in NO2, then number of moles of NO2 is( )0.05

( )0.5

( )0.04

( )0.4

Single Answer

1223.01 x 10^22 Ag^+ ions is present in( )8.5 g AgNO3

( )85 grams AgNO3

( )0.85 g AgNO3

( )18.5 g AgNO3

Single Answer

123One mole of SO2 contains( )6.02 x 10^23 atoms of sulphur

( )4 gram atoms of SO2

( )6.02 x 10^23 atoms of oxygen

( )18.1 x 10^23 molecules of SO2

Single Answer

124The largest number molecules are present in( )2.8 g of CO

( )4.8 g of C2H5OH

( )3.6 g of H2O

( )5.4 g of N2O5

Single Answer

125The mass of one mole of proton is( )1.008 mg

( )1.008 g

( )1.673 g

( )0.184 g

Single Answer

12610 cm3 of Cl2 gas at STP has molecules( )1.003 x 10^22

( )1.003 x 10^23

( )2.7 x 10^20

( )2.7 x 10^21

Single Answer

1274.6 grams of C2H5OH and 6 grams of C2H6 have( )C2H5OH has greater number of molecules

( )C2H6 has greater number of molecules

( )Equal number of molecules

( )C2H6 has less mass of carbon

Single Answer

128The volume occupied by 1.4 g of N2 at STP is( )1.12 dm3

( )112 cm3

( )22.4 dm3

( )2.24 dm3

Single Answer

129A limiting reactant is the one which( )Gives the maximum amount of the product which is required

( )Is taken in lesser quatity in grams as compared to other reactants

( )Gives the minimum amount of the product under consideration

( )Is taken in lesser quantity in volume as compared to the other reactants

Single Answer

130When one mole ofeach of the following is completely burned in oxygen, which gives the largest mass of carbon dioxide( )Carbon monoxide

( )Diamond

( )Methane

( )Ethane

Single Answer

131Methane reacts with steam to form hydrogen and carbon monoxide as CH4 + H2O------>3H2 + CO. What volume of hydrogen can be obtained from 100 cm3 of methane (at the same temperature and pressure)( )300 cm3

( )100 cm3

( )150 cm3

( )200 cm3

Single Answer

132Hydrogen reacts with oxygen as s 2H2(g) + O2(g)-------->2H2O(l). How much gas will remain if 2 dm3 of hydrogen are reacted with 1 dm3 of oxygen at room temperature( )0

( )3 dm3

( )2 dm3

( )3 cm3

Single Answer

133How many moles of oxygen, O2 are needed for the complete combustion of two moles of butane, C4H10( )13

( )8

( )10

( )2

Single Answer

134Wha tis the maximum mass of aluminium which can be obtained from 240 g of aluminium oxide, Al2O3?( )26 g

( )108 g

( )51 g

( )127 g

Single Answer

135If four moles of sulphur dioxide are oxidized to sulphur trioxide, how many moles of oxygen molecules are required( )2.0

( )1.0

( )0.5

( )1.5

Single Answer

136When 0.1 g of magnesium is treated with an excess of hydrofluoric acid, what volume of gas at room temperature and pressure will be produced( )25 cm3

( )48 cm3

( )100 cm3

( )10 cm3

Single Answer

137Quicklime (calcium oxide) is manufactured by heating limestone (calcium carbonate) CaCO3-------->CaO + CO2, What mass of quicklime can be produced by heating one kg of limestone( )56/100 kg

( )28/204 kg

( )28/100 kg

( )56/124 kg

Single Answer

138The mass of sulphur which combines with 24 grams oxygen to form SO2( )24 grams

( )8 grams

( )12 grams

( )32 grams

Single Answer

139The mass of Al2S3 formed when 20 grams Al reacts completely with S is( )55.55 g

( )60 g

( )50.55 g

( )50 g

Single Answer

140Ethanol burns in O2 completely accoding to reaction C2H5OH + 3 O2---------->2CO2 + 3H2O. The mass of O2 needed to burn 0.1 mole of C2H5OH is( )3.2 g

( )32 g

( )5.6 g

( )9.6 g

Single Answer

1411.12 dm3 of N2 gas at STP has mass of N2 gas( )2.4 g

( )14 g

( )1.4 g

( )2.8 g

Single Answer

142A beaker contains 9 grams of water. The number of hydrogen atoms is( )6.02 x 10^24

( )6.02 x 10^23

( )3.01 x 10^23

( )3.01 x 10^24

Single Answer

143A reactant will be limiting reactant if it gives( )Gives zero moles of the product

( )Least number of moles of the product

( )Which gives reversible reaction

( )Highest number of moles of the product

Single Answer

144In the reaction 2N2H4 + N2O4--------->3N2 + 4H2O; 100 grams of each reactant is combined together, then( )N2O4 is limiting reactant

( )Reactants are completely converted to the products

( )Reaction is reversible

( )N2H4 is limiting reactant

Single Answer

1450.5 mole of CH4 and 0.5 mole of SO2 gases have equal( )Mass in grams

( )Volume

( )Number of molecules

( )Total number of atoms

Single Answer

146In reaction CH4 + 2O2--------->CO2 + 2H2O; 8 grams of complete burning of CH4 gives 18 grams CO2. The percentage yield is( )89.89%

( )81.81%

( )90.90%

( )84.84%

Single Answer

147When CaCO3 is heated it decomposes according to equation CaCO3(s)----------->CaO(s) + CO2(g). When 4.5 Kg CaCO3 is heated 2.5 Kg CaO is formed. The percentage yield is( )99.2%

( )90.5%

( )96.2%

( )99.5%

Single Answer

148The number of moles of CO2 which contain 8.0 g of oxygen( )0.25

( )1.0

( )0.50

( )1.50

Single Answer

149Mass of oxygen needed to react with 27 g aluminium to form Al2O3 according to the equation 2Al + 3/2 O2-------->Al2O3 is( )32 g

( )16 g

( )24 g

( )8 g

Single Answer

150The phenomenon of isotopy was first discovered by( )Rutherford

( )Bohr

( )Dalton

( )Soddy

Single Answer

151The atomic mass of an element is expressed in( )Kilograms

( )Ounce

( )Grams

( )A.m.u

Single Answer

152When NH3 gas reacts with HCl white fumes are formed which are chemically( )HCl fumes

( )Cl-

( )NH4^+

( )NH4Cl

Single Answer

153When carbon dioxide passes through lime water, Ca(OH)2 aqueous solution, white precipitate is formed. It is( )CaO

( )CaCO3

( )H2CO3

( )Ca2CO3

Single Answer