CBSE Questions for Class 9 Chemistry Atoms And Molecules Quiz 12 - MCQExams.com

The average relative atomic mass of chlorine is 35.It consists of two naturally occurring isotopes chlorine-35 and chlorine-What is the fractional abundance of chlorine-37?
  • 0.3650
  • 0.2200
  • 0.3550
  • 0.4500
The average molecular mass of a mixture of gas containing nitrogen and carbon dioxide isThe mixture contains 280 g of nitrogen. Therefore, the amount of $${ CO }_{ 2 }$$ present in the mixture is :
  • 440 g
  • 44 g
  • 4.4 g
  • 880 g
The time in seconds it would take to spend Avogadro's number of rupees at the rate of $$10$$ lakh rupees per second is :
  • $$6.023\times 10^{17}$$
  • $$6.023\times 10^{23}$$
  • $$6.023\times 10^{10}$$
  • $$\displaystyle 6.023\times 10^{19}$$
Which among the following is true about one mole of a gas?
  • It always occupies 1 litre.
  • It always occupies 2 litres.
  • It can occupy any volume at S.T.P.
  • It always occupies a fixed volume at N.T.P.
$$2.40\  g$$ of the chloroplatinate of a mono acid-base on ignition gave $$0.8\  g$$ of platinum. Calculate the molecular weight of the base. (Given the atomic weight of $$Pt = 195\ g/mol$$).
  • $$87.5\  g/mol$$
  • $$34.6\ g/mol$$
  • $$102.4\  g/mol$$
  • $$111.0\ g/mol$$
$$0.3$$ g of chloroplatinic acid of an organic diacidic base left $$0.09$$ g of platinum on ignition. The molecular weight of the organic base is :
  • 120
  • 240
  • 180
  • 60
What is the molar mass of diacidic organic Lewis base, if $$12$$ g of chloroplatinate salt on ignition produced $$5$$ g residue?
  • $$52$$
  • $$58$$
  • $$88$$
  • None of the above
The percentage by mole of $${ NO }_{ 2 }(g)$$ in a mixture of $${ NO }_{ 2 }(g)$$ and $$NO(g)$$ having average molecular mass 34 is :
  • 25%
  • 20%
  • 40%
  • 75%
Which of the following statements is correct about the reaction given below?
$$\displaystyle 4Fe\left ( s \right )+3O_{2}\left ( g \right )\rightarrow 2Fe_{2}O_{3}\left ( g \right )$$
  • The total mass of reactants $$=$$ Total mass of the products. It follows the law of conservation of mass.
  • The total mass of reactants $$=$$ Total mass of the products. Therefore, the law of multiple proportions is followed.
  • Amount of $$Fe_{2}O_{3}$$ can be increased by taking any one of the reactants (iron or oxygen) in excess.
  • Amount of $$Fe_{2}O_{3}$$ produced will decrease if the amount of any one of the reactants (iron or oxygen) is taken in excess.
A glass vessel weighs $$50$$ g when empty, $$148.0$$ g when completely filled with liquid of density $$0.98 g\ { ml }^{ -1 }$$ and  $$50.5$$ g when filled with an ideal gas at $$760$$ mm of Hg at $$300$$ K. Determine the molecular weight of the gas.
  • 183 g/mol
  • 143 g/mol
  • 123 g/mol
  • 150 g/mol
Which of the following is a suitable example for illustrating the law of conservation of mass?
 (Atomic mass of O = 16 g/mol, H = 1 g/mole)
  • $$18$$ g of water is formed by the combination of $$16$$ g oxygen with $$2$$ g of hydrogen.
  • $$18$$ g of water in liquid state is obtained by heating $$18$$ g of ice.
  • $$18$$ g of water is completely converted into vapour state on heating.
  • $$18$$ g of water freezes at $$4^oC$$ to give same mass of ice.
The most accurate statement with regard to the significance of Avogadro's number, $$6.02 \times {10}^{23}$$.
  • It is the conversion factor between grams and atomic mass units
  • It is a universal physical constant just as the speed of particle
  • It is the number of particles that is required to fill a $$1$$-liter container
  • It is the inverse diameter of an $$H$$ atom
  • It is the number of electrons in the universe
$$\displaystyle n_{1}$$ g of substance X reacts with $$\displaystyle n_{2}$$ g of substance Y to form $$\displaystyle m_{1}$$ g of substance R and $$\displaystyle m_{2}$$ g of substance of S. This reaction can be represented as $$X + Y \rightarrow R + S$$. The relation which can be established in the amounts of the reactants and the products will be :
  • $$\displaystyle n_{1}-n_{2}=m_{1}-m_{2}$$
  • $$\displaystyle n_{1}+n_{2}=m_{1}+m_{2}$$
  • $$\displaystyle n_{1}=n_{2}$$
  • $$\displaystyle m_{1}=m_{2}$$
The correct increasing order of molecular masses is:
  • $$H_{2}O > H_{2}S > CO_{2} > SO_{2}$$
  • $$H_{2}O > H_{2}S < CO_{2} > SO_{2}$$
  • $$H_{2}O < H_{2}S < CO_{2} < SO_{2}$$
  • $$H_{2}O > H_{2}S > CO_{2} < SO_{2}$$
A charged particle formed by the loss or gain of electrons during a compound formation is called an ..... 
  • ion
  • Cation
  • Anion
  • Positron
Molecules are made up of ..........
  • electrons
  • protons
  • neutrons
  • atoms
  • none of these
$$1.375$$ g of cupric oxide was reduced by heating in a current of hydrogen and the weight of copper obtained was $$1.098$$ g. In another experiment, $$1.156$$ g of copper was dissolved in nitric acid and the resulting solution was evaporated to dryness. The residue of copper nitrate when strongly heated was converted into $$1.4476$$ g of cupric oxide. State the law illustrated by these chemical combinations.
  • Law of reciprocal proportion
  • Law of multiple proportion
  • Law of constant composition
  • None of these
The atomic weight of silicon is $$28.086$$ and that of oxygen is $$15.9994$$ (on the $$C^{12}$$ scale). Calculate the mass in grams of a single molecule of $$SiO_2$$.
  • $$9.977\times 10^{-23}gm$$
  • $$9.8\times 10^{-22}gm$$
  • $$1\times 10^{-22}gm$$
  • $$6.6\times 10^{-23}gm$$
If 10$$^{21}$$ molecules are removed from 200 mg of CO$$_{2}$$, the number of moles of CO$$_{2}$$ left is :
  • $$2.88 \times 10^{-3}$$
  • $$28.8 \times 10^{-3}$$
  • $$0.288 \times 10^{-3}$$
  • $$1.66 \times 10^{-3}$$
Two gaseous samples of the same compound were analyzed. One contained 1.2 g of carbon and 3.2 g of oxygen. The other contained 27.3% carbon and 72.7% of oxygen. The experimental data follows:
  • Law of conservation of mass
  • Law of definite proportion
  • Law of reciprocal proportion
  • Law of multiple proportion
If we assume that one-sixth the mass of an atom of $$^{12}C$$ isotope is taken as the reference, the mass of one molecule of oxygen will:
  • be double its original value
  • be half its original value
  • be the same
  • increase by four fold
How many oxygen atoms will be present in $$88\  g$$ of $$CO_2$$?
  • $$24.08 \times 10^{23}$$
  • $$6.023 \times 10^{23}$$
  • $$44 \times 10^{23}$$
  • $$22 \times 10^{24}$$
How many grams of $$CaO$$ are required to react with $$852\ g$$ of $$P_4O_{10}$$ according to below given reaction:
$$6CaO+P_4O_{10}\to 2Ca_3(PO_4)_2$$
  • 852 g
  • 1008 g
  • 85 g
  • 7095 g
How many moles of magnesium phosphate, $$Mg_3(PO_4)_2$$ will contain 0.25 mole of oxygen atoms ? 
  • $$0.02$$
  • $$3.125 \times 10^{-2}$$
  • $$1.25 \times 10^{-2}$$
  • $$2.5 \times 10^{-2}$$
Number of atoms in 558.5 g of Fe:

(Atomic mass of Fe = 55.85 u)
  • $$15.09 \times 10^{25}$$
  • $$6.023 \times 10^{24}$$
  • $$38$$
  • $$ 5 \times 2\times 6.023 \times 10^{23}$$
Who first gave the concept of 'atom'?
  • John Dalton
  • Aristotle
  • Kanada
  • Kapila
Specific volume of cylindrical virus particles is $${ 6.02\quad \times  }{ 10 }^{ -2 }$$ cc/gm whose radius and length are 7 $$\mathring A$$ and 10 $$\mathring A$$, respectively. If $${ N }_{ A }=6.02\times\  { 10 }^{ 23 }$$ find molecular weight of virus.
  • $$15.4 $$ kg/mol
  • $$1.54\quad \times \quad { 10 }^{ 4 }$$ kg/mol
  • $$3.08\quad \times \quad { 10 }^{ 4 }$$ kg/mol
  • $$1.54\quad \times \quad { 10 }^{ 3 }$$ kg/mol
How many molecules are present in one gram of hydrogen ($$H_2$$)?
  • $$6.023 \times 10^{23}$$
  • $$6.023 \times 10^{22}$$
  • $$3.01 \times 10^{23}$$
  • $$3.0125 \times 10^{-12}$$
If we assume $$\dfrac {1}{6}th$$ part instead  of $$\dfrac {1}{12}th$$ part of weight of $$^{12}C$$ as on amu. The molecular mass of water will be
  • $$9$$
  • $$18$$
  • $$36$$
  • $$10.5$$
$$25\ g$$ of $$M{Cl}_{4}$$ contains $$0.5$$ mole chlorine then its molecular weight is:
  • $$100\ g\ {mol}^{-1}$$
  • $$200 \ g\ {mol}^{-1}$$
  • $$150\ g\ {mol}^{-1}$$
  • $$400\ g\ {mol}^{-1}$$
P and Q are two elements which form $${ P }_{ 2 }{ Q }_{ 3 }$$ and $${ PQ }_{ 2 }$$. If 0.15 mole of $${ P }_{ 2 }{ Q }_{ 3 }$$ weight 15.9 g and 0.15mole of $${ PQ }_{ 2 }$$ weight 9.3 g. what are atomic weights of P and Q respectively?
  • 18 and 26 
  • 26 and 26
  • 26 and 18
  • 18 and 18
Zinc sulphate contains 22.65% $$Zn$$ and 43.9% $${H}_{2}O$$. If the law of constant proportions is true, then the mass of zinc required to give 40 g crystal will be:
  • 9.06 g
  • 90.6 g
  • 0.906 g
  • 906 g
Which of the following cations does not form soluble complex with excess NaOH solution as well as excess $$NH_4OH$$ solution ?
  • $$Cu^{+2}$$
  • $$Al^{+3}$$
  • $$Fe^{+3}$$
  • None of these
Of two oxides of iron, the first contained $$22$$% and the second contained $$30$$% of oxygen by weight. The ratio of weights of iron in the two oxides that combine with the same weight of oxygen is
  • $$1 : 2$$
  • $$3 : 2$$
  • $$1 : 1$$
  • $$2 : 1$$
Hydrogen combines with oxygen to form $$H_2O$$ in which 16 g of oxygen combine with 2 g of hydrogen. Hydrogen also combines with carbon to form $$CH_4$$ in which 2 g of hydrogen combine with 6 g of carbon.If carbon and oxygen combine together then they will do show in the ratio of 
  • 13 : 32
  • 6 : 16
  • 1 : 2
  • 12 : 24
The mass of one molecule of carbon dioxide is:
  • $$26.49\times { 10 }^{ 24 }g$$
  • $$44\ g$$
  • $$7.30\times { 10 }^{ -23 }g$$
  • $$22\ g$$
Molecular mass of one mole of $$H_{2}SO_{4}$$ is ______.
  • $$98 a.m.u.$$
  • $$1.627\times 10^{-22}g$$
  • Both $$A$$ & $$B$$
  • $$1.627\times 10^{-25}g$$
The weight of one molecule of a compound $$C_{60}$$$$H_{122}$$ is ?
  • $$1.3 \times 10^{-20}g$$
  • $$5.01 \times 10^{-21}g$$
  • $$3.72\times 10^{13}g$$
  • $$1.4 \times 10^{-21}g$$
Atomic radius is measured in?
  • Centimetres (cm)
  • Nanometres (nm)
  • Metres (m)
  • Kilometres (Km)
If the mass of neutrons is doubled and that of protons is halved, the molecular mass of $$H_2O$$ containing only $$H^1$$ and $$O^{16}$$ atoms will _____________.
  • increase by about $$25\%$$
  • decrease by about $$25\%$$
  • increase by about $$16\%$$
  • decrease by about $$16\%$$
At  $$25^oC$$, $$K_{sp}$$ value of $$AgCl$$ in water is $$1.8 \times 10^{-10}$$. If $$10^{-5}$$ moles of $$Ag^+$$ are added to this solution then $$K_{sp}$$ will be
  • $$3.13\times 10^{-10}$$
  • $$1.8 \times 10^{-10}$$
  • $$5.04 \times 10^{-5}$$
  • $$1.8 \times 10^{-8}$$
The number of moles in $$ 2 \times 10^{24} $$ atoms of iron are
  • 3.3
  • 4.5
  • 5.2
  • 2.1
Which of the following weighs the least?
  • 2 g atom of N
  • $$ 3\times 10^{25} $$ atoms of carbon
  • 1 mole of sulphur
  • 7 g silver
Number of atoms in 560 g of Fe (atomic mass = 56 u) is
  • Twice that of 70 g N
  • Half that of 20 g H
  • Equal to that of 70 g N
  • None of these
The compound which does not exist is 
  • $$BF_3$$
  • $$AlF_3$$
  • $$AlI_3$$
  • $$TlI_3$$
  • $$TlF_3$$
The number of gram molecules of oxygen in $$  6.02 \times 10^{24}  $$ CO molecules is:-
  • 10 $$ \mathrm{g} $$ molecules
  • 5 $$ \mathrm{g} $$ molecules
  • 1 $$ \mathrm{g} $$ molecules
  • 0.5 $$ \mathrm{g} $$ molecules
A gas $$X$$ is $$8$$ times heavier than hydrogen and the other gas $$Y$$ is two times heavier than $$X$$ . The mol. wt. of $$Y$$ is: 
  • $$3$$
  • $$8$$
  • $$16$$
  • $$32$$
How many moles of $$CO_{ 2 }$$ are present in 220 mg ?
  • 5 moles
  • 0.005 mole
  • 5000 moles
  • 10 moles
A gas cylinder of the capacity of 20 $$dm^{3}$$ is filled with gas $$X$$, the mass of which is $$10\ gm$$. When the same cylinder is filled with hydrogen gas at the same temperature and pressure the mass of the hydrogen is $$2 \ gm$$ hence the relative molecular mass of the gas is:
  • 5
  • 10
  • 15
  • 20
Which of the following formulae is not accurately depicted?
  • Molar mass $$=\dfrac {Mass\ of\ substance}{Moles\ of\ substance}$$
  • Number of moles of a substance $$=\dfrac {Mass\ of\ substance}{Molar\ mass}$$
  • Number of molecules $$=\dfrac {Mass\ of\ the\ substance}{Molar\ mass} \times N_A$$
  • Mole $$\times $$ Molar mass = Number of molecules
0:0:1


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