Q 1 – If 12 grams of carbon has n atoms, then the number of atoms in 12 grams of magnesium will be:
(a) 2n
(b) 3n
(c) n/2
(d) n
Q 2 – Which of the following is correct pair of elements and its symbol?
(a) Silver – Si
(b) Sodium – So
(c) Potassium – Pt
(d) Sulphur – S
Q 3 – A student heats 25g of reactant ‘A’ with 50g of reactant ‘B’. He obtains 50g of product ‘C’ and recovers 25 g of unreacted ‘B’. Which of the following law is confirmed in the following reaction?
(a) Law of constant proportion
(b) Law of conservation of mass
(c) Law of conservation of mass and Law of constant proportion
(d) Law of multiple proportion
Q 4 – How many moles are present in 40 g of He?
(a) 10 moles
(b) 11 moles
(c) 13 moles
(d) 12 moles
Q 5 – Identify the symbol used to represent Avogadro’s number.
(a) MA
(b) AO
(c) AN
(d) NA
Q 6 – Law of conservation of mass can be derived from which postulate of Dalton’s atomic theory?
(a) Atoms of a given element have same mass and chemical properties.
(b) Matter is made of tiny particles.
(c) Atom can neither be created nor destroyed.
(d) The relative number and kind of atoms are constant in a given compound.
Q 7 – Valency of hydrogen is 1 and that of sulphur is 2. What should be the formula of hydrogen sulphide?
(a) HS
(b) H2S2
(c) HS2
(d) H2S
Q 8 – Calculate the number of Mg atoms in 0.024 g of Mg
(a) 6.022 × 1021 Mg atoms
(b) 6.220 × 1023 Mg atoms
(c) 6.022 × 1020 Mg atoms
(d) 6.022 × 1025 Mg atoms
Q 9 – Which of the following is the major drawback of Dalton’s atomic theory?
(a) Atoms of an element have exactly the same mass.
(b) Atoms are indivisible.
(c) Atoms of different elements have different masses.
(d) All of the above
Q 10 – One atomic mass unit is a mass unit equal to exactly one twelfth (1/12th) the mass of one atom of ___________.
(a) Carbon-12
(b) Nitrogen -14
(c) Carbon-10
(d) Silicon-14
Q 11 – If all the reactants in a chemical reaction are completely used, which of the following statements accurately describes the relationship between the reactants and the products?
(a) The reactants must contain more complex molecules than the products do.
(b) The products must have different physical state than the reactants.
(c) The total mass of the reactants must equal the total mass of the products.
(d) The density of the reactants must equal the density of the products.
Q 12 – One mole of molecules may not be equal to:
(a) 6.022 x 1023 number of molecules
(b) Given number of particles (N)
(c) Avogadro number
(d) Molecular mass in grams
Q 13 – 9 grams of water decompose to give:
(a) 4g oxygen and 16g hydrogen
(b) 2g hydrogen and 1g oxygen
(c) 8g oxygen and 1g hydrogen
(d) none of these
Q 14 – Who gave the Law of constant proportions?
(a) Cavendish
(b) Proust
(c) Dalton
(d) Lavoisier
Q 15 – According to Law of conservation of mass, mass of reactants will be equal to the mass of :
(a) Catalysts
(b) Products
(c) Apparatus used f or reaction
(d) Gases evolved
Q 16 – How do atoms usually exist in nature?
(a) In the form of molecules
(b) In the form of ions
(c) In the free state
(d) In the form of molecules and Ions
Q 17 – What is the mass of 0.5 mole of Hydrogen atom
(a) 2.0 g
(b) 1.5 g
(c) 1 g
(d) 0.5 g
Q 18 – The number of atoms present in one molecule of an element is called as:
(a) Empirical formula
(b) Molecule
(c) Atomicity
(d) Compound
Q 19 – Calculate the formula unit mass of ZnCl2? (Atomic Mass of Zn = 65.38 u , Cl = 35.5 u )
(a) 136.38 u
(b) 124.57 u
(c) 123.78 u
(d) 111.24 u
Q 20 – Which of the following pair of elements represents a mole ratio of 1:1?
(a) 20 g of sodium and 20 g of calcium
(b) 7 g of nitrogen and 12 gm of sodium
(c) 10 g of calcium and 6 g of carbon
(d) 14 g of nitrogen and 24 g of magnesium
Q 21 – Which of the following is the correct IUPAC symbol f or the element Cobalt?
(a) Co
(b) Cb
(c) C
(d) none of these
Q 22 – Which of the following can be used to see atoms?
(a) Scanning tunneling microscope
(b) Microscope
(c) Most powerful microscope
(d) Optical microscope
Q 23 – Which one of the following is the modern symbol of Gold?
(a) Gl
(b) Go
(c) Si
(d) Au
Q 24 – NaCl molecule is made of which of the following ions?
(a) Na cation and Cl anion
(b) Cl cation and Na anion
(c) Both Na and Cl cation
(d) Both Na and Cl anion
Q 25 – An atom has a mass number of 23 and atomic number 11. The number of protons are ________.
(a) 11
(b) 12
(c) 23
(d) 44
Q 26 – The balancing of chemical equation is based upon:
(a) Law of conservation of mass
(b) Law of multiple proportions
(c) Law of definite proportion
(d) Law of combining volumes
Q 27 – The number of moles of oxygen atoms in two moles of nitric acid is:
(a) 2
(b) 4
(c) 8
(d) 6
Q 28 – During a chemical reaction, the sum of the masses of the reactants and products remains unchanged. This is known as
(a) Law of conservation of mass
(b) Law of multiple proportion
(c) Law of constant proportion
(d) None of these
Q 29 – Who was the first to use the symbols f or elements?
(a) Joseph L Proust
(b) Berzillius
(c) Antoine L Lavoisier
(d) Dalton
Q 30 – Valency of Calcium element is:
(a) 4
(b) 5
(c) 2
(d) 3
Q 31 – The mass of 0.5 moles of Water molecules is:(Atomic mass, H =1; O = 16)
(a) 27 g
(b) 0.5 g
(c) 9 g
(d) 18 g
Q 32 – Who stated the Law of constant proportions ?
(a) Thomson
(b) Joseph proust
(c) Dalton
(d) Cavendish
Q 33 – Which constituent of air is monoatomic?
(a) Argon
(b) Water vapour
(c) Oxygen
(d) Nitrogen
Q 34 – The chemical symbol for nitrogen gas is
(a) Ni
(b) N2
(c) N+
(d) N
Q 35 – The chemical symbol for sodium is
(a) So
(b) Sd
(c) NA
(d) Na
Q 36 – Which of the following would weigh the highest?
(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O
Q 37 – Which of the following has maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CO4
Q 38 – Which of the following correctly represents 360 g of water?
(i) 2 moles of H2O
(ii) 20 moles of water
(iii) 6.022 × 1023 molecules of water
(iv) 1.2044 × 1025 molecules of water
(a) (i)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
Q 39 – 3.42 g of sucrose are dissolved in 18 g of water in a beaker. The number of oxygen atoms in the solution are
(a) 6.68 × 1023
(b) 6.09 × 1022
(c) 6.022 × 1023
(d) 6.022 × 1021
Q 40 – A change in the physical state can be brought about
(a) only when energy is given to the system
(b) only when energy is taken out from the system
(c) when energy is either given to, or taken out from the system
(d) without any energy change
Q 41 – The relative molecular mass of Na2S2O3.5H2O is ( Atomic mas of Sodium = 23 u , Sulphur = 32 u , Oxygen = 16 u , Hydrogen = 1 u )
(a) 250 amu
(b) 250 g
(c) 248 amu
(d) 248 g
Q 42 – Which of the following has maximum number of atom? ( For atomic masses refer to below question )
(a) 18 g H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CH4
Q 43 – Percentage of calcium in calcium carbonate is ( Atomic mas of Calcium = 40 u , Carbon = 12 u , Oxygen = 16 u )
(a) 40
(b) 30
(c) 48
(d) 36
Q 44 – Which has maximum number of molecules? (Atomic mas of Carbon = 12 u , Oxygen = 16 u , Nitrogen = 14 u , Hydrogen = 1 u )
(a) 1 g of CO2
(b) 1 g of N2
(c) 1 g of H2
(d 1 g of CH4
Q 45 – What mass of carbon dioxide (CO2) will contain 3.011 × 1023 molecules? (Atomic mas of Carbon = 12 u , Oxygen = 16 u )
(a) 11.0 g
(b) 22.0 g
(c) 4.4 g
(d) 44.0 g
Q 46 – The value of Avogadro’s constant is:
(a) 6.0 × 1024
(b) 6.01 × 1022
(c) 6.022 × 1023
(d) 6.022 × 10–23
Q 47 – How many times an atom of sulphur is heavier than an atom of carbon? (Atomic mas of Sulphur = 32 u , Carbon = 12 u )
(a) 32 times
(b) 12 times
(c) 8/3 times
(d) 12/32 times
Q 48 – The number of oxygen atoms in 4.4 g of CO2 is approx. (Atomic mas of Carbon = 12 u , Oxygen = 16 u )
(a) 6 × 1022
(b) 6 × 100
(c) 12 × 1023
(d) 1.2 × 1023
Q 49 – Which of the following represents 12 u?
(a) Mass of 1 hydrogen atom
(b) Mass of C-12 atom
(c) Mass of O-16 atom
(d) 1/12th of mass of C-12 atom.
Q 50 – Which of the following would weigh the highest?
(a) 0.2 mole of sucrose (C12H22O11)
(b) 2 moles of CO2
(c) 2 moles of CaCO3
(d) 10 moles of H2O
Q 51 – The molecule having an atomicity of 4 is:
(a) Sulphate molecule
(b) Ozone molecule
(c) Phosphorus molecule
(d) Methane molecule
Q 52 – Fill in the Blanks.
a) In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always ______
b) The formula unit mass of a substance is a sum of the atomic ______ of all its constituent atoms.
c) The relative mass of atoms of all elements is obtained by comparing them with the mass of a _______ atom.
Q 53 – Match the Column A to B
| A | B |
| 1. 1 mole of carbon atoms | (i) 1 g of H atoms |
| 2. 1 mole of molecules | (ii) Molecular mass in gram |
| 3. 1 mole of hydrogen atoms | (iii) Relative mass of those particles in gram |
| 4. 1 mole of any particle (atoms, molecules, ions) | (iv) 12-gram carbon atoms |