CBSE Questions for Class 9 Chemistry Atoms And Molecules Quiz 8 - MCQExams.com

Greek philosophers,  ______and _______suggested that matter is made up of tiny indivisible particles called atoms.
  • Democritus and Leucippus
  • Dalton and Rutherford
  • Einstein and Kanad
  • Democritus and Dalton
Democritus' atomic theory states that:
  • atoms are homogeneous
  • atoms are indestructible
  • atoms are solid but invisible
  • all of the above
Which of the following is the unit of molar mass?
  • u/mole
  • g/mole
  • g/litre
  • None of above.
Dalton's theory fails to determine the existence of:
  • molecules
  • compounds
  • allotropes
  • All of the above
According to Democritus, matter is made up of:
  • small, indivisible particles
  • large particles
  • large, divisible particles
  • None of above
Which of the following scientist did not believe in atomic theory at all?
  • Aristotle
  • Democritus
  • Rutherford
  • Proust
Who thought that all materials were made of the four elements, earth, fire, water, and air?
  • Dalton
  • Aristotle
  • Thomson
  • Chadwick
The theory that the universe is composed of two elements, the atoms, and the void, in which they exist and move was given by:
  • Bohr
  • Dalton
  • Leucippus
  • Werner
Which of the following is a postulate of Dalton's atomic theory?
  • All matter consists of indivisible particles called atoms.
  • The atom is the smallest unit of matter that can take part in a chemical reaction.
  • Atoms of the same element can combine in the same ratio to form compounds.
  • All of the above
Which of the following is a merit of Dalton's atomic theory?
  • Laws of chemical combination
  • The distinction between the fundamental particle of an element (atom) and that of a compound (molecule)
  • Both A and B
  • None of the above
Dalton's theory of same element have same mass and properties was proved wrong with the invention of:
  • molecules
  • isotopes
  • neutrons
  • compounds
Which of the following explains Democritus' atomic model?
  • None of the above
Dalton had suggested that an atom is indivisible. 
  • True
  • False
Which of the following is a wrong representation of atom and it's ion?
  • $$Rb/ Rb^{-}$$
  • $$Mg/ Mg^{2+}$$
  • $$F/F^{-}$$
  • $$Li/Li^{+}$$
  • $$Br/ Br^{-}$$
What is the approximate mass of $$Ca(NO_3)_2$$?
(Given- Atomic mass of $$Ca = 40, N = 14, O = 16$$)
  • $$70$$
  • $$82$$
  • $$102$$
  • $$150$$
  • $$164$$
Among the following, which one can not be further broken down by chemical means?
  • Cation
  • Inert Gas
  • Crystal
  • Anion
  • Element
Ionic species with a positive charge called as : 
  • cation
  • inert Gas
  • crystal
  • anion
  • element
Find the best option among the following about the simplest unit of water that retains its properties :
  • A molecule
  • A mixture of compounds
  • An isotope
  • An isomer
  • An acid salt
All of the following are compounds except :
  • copper sulfate
  • carbon dioxide
  • washing soda
  • air
  • lime
The molar mass of $$\displaystyle Al{ Cl }_{ 3 }$$ is:
  • $$67.9$$ g/mol
  • $$106.5$$ g/mol
  • $$62.5$$ g/mol
  • $$133.5$$ g/mol
One atomic mass unit is equal to?

(Given, mass of one carbon-12 atom $$= 1.992 \times 10^{-23}$$)
  • $$1.66\times 10^{-27}g$$
  • $$1.66\times 10^{-24}g$$
  • $$1.66\times 10^{-23}g$$
  • $$1.66\times 10^{-25}g$$
Statement 1: One mole of $$CO_2$$ has a greater mass than $$1$$ mole of $$H_2O$$.
Statement 2: The molecular mass of $$CO_2$$ is greater than the molecular mass of $$H_2O$$.
  • Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1

  • Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation of Statement 1

  • Statement 1 is correct but Statement 2 is not correct

  • Statement 1 is not correct but Statement 2 is correct

  • Both statements are incorrect
Find the accurate statement for the significance of Avogadro's number ?
  • It is the conversion factor between grams and pounds.
  • It is a universal physical constant just as the speed of light.
  • 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.
All atoms of the same element have :
  • different numbers of electrons.
  • equal number of protons.
  • different numbers of neutrons.
  • different numbers of protons.
  • equal number of neutrons.
Molar mass of ethanol $$(C_2H_5OH)$$ is:
(Atomic masses: C = 12 u, H = 1 u, O = 16 u)
  • $$34$$
  • $$38.9$$
  • $$46$$
  • $$45.1$$
  • $$62.1$$
An atom differs from its ion in:
  • Nuclear charge
  • Mass number
  • Number of electrons
  • Number of neutrons
Which of the following is not part of the atomic theory?
  • Compounds are made up of combinations of atoms.
  • All atoms of a given element are alike.
  • All matter is composed of atoms.
  • A chemical reaction involves the rearrangement of atoms.
  • The atom is mainly empty space.
The size of the nucleus is measured in _______ units.
  • $$amu$$
  • angstrom
  • fermi
  • $$cm$$
Who first coined the term 'atomos' meaning indivisible?
  • Rutherford
  • Thomson
  • Aristotle
  • Democritus
  • Dalton
The molar mass of $$CaCO_3$$ is :
  • $$68$$ g$$/$$mol
  • $$75$$ g$$/$$mol
  • $$82$$ g$$/$$mol
  • $$100$$ g$$/$$mol
  • $$116$$ g$$/$$mol
Which of the following will not be affected by changes in temperature and pressure?
  • Density
  • Equilibrium constant
  • Molar mass
  • Freezing point
  • Molarity
Which of the groups below represents the correct relationship in order from smallest (or simplest) to largest (or more complex)?
  • Matter - element - compound - electron - atom
  • Electron - element - atom - compound - matter
  • Electron - atom - element - matter - compound
  • Electron - atom - element - compound - matter
  • Atom - electron - element - compound - matter
Which law states that in a chemical reaction, the total mass of the products is equal to the total mass of the reactants?
  • Law of constant proportions
  • Law of conservation of energy
  • Law of conservation of mass
  • Law of multiple proportions
A symbol of an element does not convey information about :
  • Atomic number
  • Atomic weight
  • Mass number
  • All the above
Barium chloride reacts with sodium sulfate to form barium sulfate and sodium chloride. Then, according to the law of conservation of mass:
  • The total mass of reactants, barium chloride, and sodium sulfate taken is greater than the total mass of products, barium sulfate, sodium chloride formed.
  • The total mass of reactants, barium chloride, and sodium sulfate taken is less than the total mass of products, barium sulfate, sodium chloride formed.
  • The total mass of the reactants is equal to the total mass of products.
  • None of the above
The symbols of lead and mercury are _________ respectively.
  • $$Hg, Pb$$
  • $$Pb, Hg$$
  • $$Le, Me$$
  • $$Ld, My$$
A balanced chemical equation  supports
  • Law of chemical equilibrium
  • Law of conservation of energy
  • Law of conservation of mass
  • None of these
$$1\ amu = \dfrac{1}{12}$$ the mass of one:
  • $$C-12$$ atom
  • $$N$$ atom
  • $$O$$ atom
  • $$H$$ atom
Identify the correct statement(s) from the following:
  • The shorthand representation of a molecule of a substance (element or compound) in terms of symbols and subscript numbers is known as the chemical formula.
  • Atoms of different elements combine in a certain fixed ratio to form a compound.
  • All chemical compounds are represented by their respective chemical formulae.
  • Symbols of all elements are derived from their Latin names.
Nitrogen reaction with oxygen to form nitrous oxide.

What will be the volume ratio of the reactants and products of the given reaction?
$$2N_{2}+O_{2}\rightarrow 2N_{2}O$$
  • 1 : 1 : 2
  • 1 : 2 : 2
  • 3 : 1 : 2
  • 2 : 1 : 2
The mass of 5 moles of $$H_2SO_4$$ is:
  • $$180\ g$$
  • $$250\ g$$
  • $$300\ g$$
  • $$490\ g$$
Which of the following is a quantity necessary to determine the molecular formula of a compound?
  • Boiling point
  • Rate of reaction
  • Molecular mass
  • Molarity (moles per litre)
  • Density
What weight of calcium contains the same number of atoms as those in $$3 g$$ of carbon?
  • $$10 g$$
  • $$20 g$$
  • $$30 g$$
  • $$40 g$$
Which of the following contains the least number of molecules?
  • 52 g of $$N_2O_5$$
  • 36 g of $$H_2O$$
  • 28 g of $$CO$$
  • 51 g $$NH_3$$
What is the mass of one molecule of oxygen?
  • $$5.31\times { 10 }^{ -23 }g$$
  • $$5.33\times { 10 }^{ 23 }g$$
  • $$5.25\times { 10 }^{ 23 }g$$
  • $$5.02\times { 10 }^{ -23 }g$$
Identify the pair of substances having the same formula unit mass.
  • Calcium chloride, potassium carbonate
  • Calcium oxide, hydrochloric acid
  • Carbon monoxide, ammonia
  • Carbon dioxide, nitrous oxide
The heaviest among the following is:
  • $$50\ g$$ of $$Fe$$
  • $$5\ moles$$ of $$N_2$$
  • $$0.1\ g \ atom$$ of $$Ag$$
  • $$0.1\ g$$ of $$Ca$$
What is the approximate molecular mass of dry air containing 78% $$N_2$$ and 22% $$O_2$$?
  • 28.88
  • 27
  • 30
  • 34
Who was the first scientist to propose that all matter was made of small spheres called atoms?
  • John Dalton (early 1800's)
  • Ernest Rutherford (1911)
  • Niel's Bohr (1913)
  • Joseph John Thomson (1897)
A smallest particle of a compound that can have the independence existence and that can retain all the properties of that compound is called as:
  • molecule
  • ion
  • atom
  • element
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 9 Chemistry Quiz Questions and Answers