CBSE Questions for Class 9 Chemistry Atoms And Molecules Quiz 5 - MCQExams.com

An ionic compound of element MM and chlorine has the formula MCl3MCl3, the molecular mass of MCl3MCl3 is 118.5 u. What is the molecular mass of the oxide of an element MM?
  • 28
  • 44
  • 72
  • 99
The difference between ions and atoms is of :
  • relative size
  • electronic configuration
  • presence of charge
  • All of the above
14 g of element X combine with 16 g of oxygen. On the basis of this information, which of the following is a correct statement?
  • The element X could have an atomic weight of 7 and its oxide is XO.
  • The element X could have an atomic weight of 14 and its oxide is X2OX2O.
  • The element X could have an atomic weight of 7 and its oxide is X2OX2O
  • The element X could have an atomic weight of 16 and its oxide is X2OX2O
Smallest particle of an element or a compound which is capable of independent existence is called:
  • atom
  • molecule
  • element
  • compound
A chemical equation is balanced in accordance with the law of
  • conservation of mass
  • multiple proportion
  • constant proportion
  • reciprocal proportion
Which law stated that 'matter is neither created nor destroyed'?
  • Law of multiple proportion
  • Law of conservation of energy
  • Law of constant composition
  • Law of conservation of mass
Which of these is not a molecule?
  • H2H2
  • ClCl
  • O3O3
  • NaClNaCl
The law of conservation of mass was given by :
  • Dalton
  • Proust
  • Lavoisier
  • Berzelius
One mole of any substance contains 6.023×10236.023×1023 particles. It was determined by
  • Berzilius
  • Avogadro
  • Dalton
  • Perin
Which atom contains exactly 15 neutrons?
  • P32P32 (atomic number =17=17)
  • S32S32 (atomic number =16=16)
  • O15O15 (atomic number =8=8)
  • N15N15 (atomic number =7=7)
Amongst the following, which has the highest molecular mass?
  • Cl2Cl2
  • N2N2
  • CH3OHCH3OH
  • NH3NH3
In a chemical reaction, when 14 g of sodium carbonate reacted with 10g of acetic acid (ethanoic acid), then it was observed that, 16.67 g of sodium acetate solution in water and 7.33 g of carbon dioxide were produced. Which law does this depicts?
  • Law of definite proportions
  • Law of conservation of mass
  • Law of constant proportions
  • Avogadro's law
Which of the following elements has the same molecular mass as its atomic mass?
  • Nitrogen
  • Neon
  • Oxygen
  • Chlorine
The value of Avogadro number is
  • 6.25×10186.25×1018
  • 6.022×10236.022×1023
  • 9650096500
  • 3.12×10183.12×1018
Any sample of pure water, irrespective of its source, contains 88.89% oxygen and 11.11 % hydrogen by mass. The data supports the:
  • Law of conservation of mass
  • Law of constant composition
  • Law of multiple proportion
  • Law of reciprocal proportion
720 g of water contains ______ moles of water.
  • 20
  • 40
  • 60
  • 80
Smallest possible unit of a compound which has independent existence is :
  • molecule
  • atom
  • ion
  • electron
The mass of NaNa present in 11.7 g of NaClNaCl is:
  • 2.3 g
  • 4.6 g
  • 6.9 g
  • 7.1 g
Since Avogadro number is 6.023×10236.023×1023 and atomic mass of nitrogen is 1414 amu, one mole of N2N2 gas will have:
  • 0.5×6.023×10230.5×6.023×1023 atoms
  • 2×6.023×10232×6.023×1023 atoms
  • 14×6.023×102314×6.023×1023 atoms
  • 28×6.023×102328×6.023×1023 atoms
Radius of atom is of the order :
  • 1010108cm1010108cm
  • 10121014cm10121014cm
  • 10141016cm10141016cm
  • 10161020cm10161020cm
One atomic mass unit is equivalent to
  • 1.67×1027g1.67×1027g
  • 1.66×1027kg1.66×1027kg
  • 1.67×1027mg1.67×1027mg
  • 1.6×1024g1.6×1024g
2.40 g of the element ZZ combines exactly with 1.6 g of oxygen to form a compound with the formula ZO2ZO2. What is the relative atomic mass of ZZ?
  • 24.0
  • 32.0
  • 48.0
  • 64.0
The mass of one atom of carbon-12 is:
  • 1 g1 g
  • 12 g12 g
  • 12×6.02×1023 g12×6.02×1023 g
  • 126.02×1023 g126.02×1023 g
An atom is:
  • The smallest particle of matter known
  • The smallest particle of a gas
  • The smallest indivisible particle of an element that can take part in a chemical change
  • Radioactive emission
Atomic theory was given by:
  • John Dalton
  • Neils Bohr
  • E. Rutherford
  • Haber Bosch
'All matter is composed of very small particles called Parmanu' was first suggested by:
  • John Dalton
  • J.J. Thomson
  • Kanad
  • William J. Crooke
Which of the following contains the largest number of molecules?
  • 0.2 mole of H22
  • 8.0 mole of H22
  • 17 g of H22O
  • 6.0 g of CO22
Which of the following weighs the most?
  • 10231023 molecules of H2H2
  • 1 mole of H2H2O
  • 1 mole of N2N2
  • 10221022 molecules of O2O2
6.4 g of oxygen will contain ______ number of oxygen molecules.
  • 6.023×10236.023×1023
  • 6.023×10226.023×1022
  • 1.2046×10231.2046×1023
  • 1.2046×10221.2046×1022
Which of the following statement is wrong?
  • An atom is electrically neutral.
  • The size of a cation is smaller than that of the corresponding atom.
  • The size of an anion is bigger than that of the corresponding atom.
  • An atom and its ion have an unequal number of protons.
Which of the following compound has formula mass of 322 u?
(H=1,C=12,0=16,Na=23,S=32,Cu=63.5)(H=1,C=12,0=16,Na=23,S=32,Cu=63.5)
  • Na2CO3.10H2ONa2CO3.10H2O
  • CuSO4.5H2OCuSO4.5H2O
  • Na2CO3.9H2ONa2CO3.9H2O
  • Na2SO4.10H2ONa2SO4.10H2O
Hydrogen combines with nitrogen in a 3:14 weight ratio to form ammonia. If every molecule of ammonia contains three atoms of hydrogen and one atom of nitrogen, an atom of nitrogen must weigh :
  • 14 times the mass of a hydrogen atom
  • 14/3 times the mass of a hydrogen atom
  • 3 times the mass of a hydrogen atom
  • 3/14 times the mass of a hydrogen atom
The sum of masses of the atoms in the molecules is known as :
  • Atomic mass
  • Molecular mass
  • Gram molecular weight
  • None of the above
The weight of one molecule of a compound of molecular formula C60H122 is:
  • 1.2×1020g
  • 5.025×1023g
  • 1.4×1021g
  • 6.023×1020g
Formula unit mass of NaHCO3 is :
  • 84 u
  • 76 u
  • 52 u
  • 64 u
Which among the following has molecular mass of 36.5 u?
  • Carbon molecules
  • Hydrogen molecules
  • Sulphur molecules
  • Hydrochloric acid
Molecular mass of nitric acid is:
  • 22 u
  • 12 u
  • 33 u
  • 63 u
Hydrogen combines with oxygen in a 1:8 weight ratio to form water. If every molecule of water contains two atoms of hydrogen and one atom of oxygen, an atom of oxygen must weigh:
  • 8 times the mass of a hydrogen atom
  • 16 times the mass of a hydrogen atom
  • 1/16 times the mass of a hydrogen atom
  • 1/8 times the mass of a hydrogen atom
1.008 grams of hydrogen combines with 35.453 g of chlorine to form 36.463 g of a pure compound (hydrogen chloride). Dalton's explanation for this experimental fact might be: 
  • One atom of hydrogen combines with 35.453 atoms of chlorine in this reaction
  • Hydrogen and chlorine atoms always combine in a 1:35 ratio.
  • Chlorine accepts hydrogen's electron to form polar covalent hydrogen chloride
  • Hydrogen and chlorine atoms aren't created or destroyed in the process so the reactant mass is the same as the product mass.
The symbol of copper is:
  • Co
  • Cr
  • Cp
  • Cu
What is the atomic mass (u) of chlorine?
  • 34
  • 35.5
  • 33
  • 35
The illustrations show a conservation-of-mass experiment. The solution in the beaker lost mass because
439573.jpg
  • materials have less mass at high temperatures
  • the mass of the reactants and products was less than 100 g
  • sodium sulfate (Na2SO4) is lighter than air
  • some of the water molecules turned into gas
In the procedure shown above, a calcium chloride solution is mixed with a sodium sulfate solution to create the products shown. Which of the following is illustrated by this activity?
439568.jpg
  • Law of conservation of mass
  • Law of definite proportions
  • Dalton's law atomic theory
  • Theory of covalent bonding
Mass can neither be created nor destroyed. This is in agreement with which law of chemical combination?
  • Law of definite proportion
  • Law of multiple proportion
  • Law of conservation of mass
  • Law of conservation of momentum

Compounds formed by metals and non-metals contain charged species which are known as:

  • cations
  • anions
  • Both A and C
  • None of the above
Which is not one of the laws of chemical combinations?
  • Law of multiple proportion
  • Law of conservation of mass
  • Law of conservation of energy
  • Law of definite proportion
Calculate the formula unit mass (u) of Na2O .
Atomic mass of Na=23 u,O=16 u
  • 60
  • 62
  • 61
  • 59
In a chemical reaction, 100g baking soda mixture containing sodium bicarbonate and vinegar on heating gives 43g of carbon dioxide gas. What mass of solid residue is left in food?
  • 54 g
  • 55 g
  • 56 g
  • 57 g
The formula unit mass of X is 342 u. Among the following, X is :
  • H2SO4
  • PbI2
  • Al2(SO4)3
  • Al(OH)3
Formula unit mass of CaCO3 is:
  • 104 u
  • 106 u
  • 100 u
  • 1144 u
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