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
(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 – Name two scientists who established the laws of chemical combination?
Q 4 – 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 5 – 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-1
(d) Silicon-14
Q 6 – Who gave the Law of constant proportions?
(a) Cavendish
(b) Proust
(c) Dalton
(d) Lavoisier
Q 7 – 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 8 – Which of the following is the correct IUPAC symbol for the element Cobalt?
(a) Co
(b) Cb
(c) C
(d) none of these
Q 9 – 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 10 – 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 11 – 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 12 – Which constituent of air is monoatomic?
(a) Argon
(b) Water vapour
(c) Oxygen
(d) Nitrogen
Q 13 – 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 14 – 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 15 – Which has maximum number of molecules?
(a) 1 g of CO2
(b) 1 g of N2
(c) 1 g of H2
(d 1 g of CH4
Q 16 – Define atomicity.
Q 17 – How many times an atom of sulphur is heavier than an atom of carbon?
(a) 32 times
(b) 12 times
Q 18 – Which of the following represents 12 u?
(a) Mass of 1 hydrogen atom
(b) Mass of C-12 atom
(c) Mass of 0-16 atom
(d) 1/12th of mass of C-12 atom.
Q 19 – 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 20 – The molecule having an atomicity of 4 is:
(a) Sulphate molecule
(b) Ozone molecule
(c) Phosphorus molecule
(d) Methane molecule
Q 21 – The chemical symbol for sodium is
(a) So
(b) Sd
(c) NA
(d) Na
Q 22 – Who was the first to use the symbols for elements?
(a) Joseph L Proust
(b) Berzillius
(c) Antoine L Lavoisier
(d) Dalton
Q 23 – The number of moles of oxygen atoms in two moles of nitric acid is:
(a) 2
(b) 4
(c) 8
(d) 6
Q 24 – Which one of the following is the modern symbol of Gold?
(a) Gi
(b) Go
(c) Si
(d) Au
Q 25 – Calculate the formula unit mass of ZnCl2?
(a) 137 u
(b) 124 u
(c) 123 u
(d) 111 u
Q 26 – 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
Q 27 – 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 28 – How many moles are present in 40 g of He?
(a) 10 moles
(b) 11 moles
(c) 13 moles
(d) 12 moles
Q 29 – What is wrong in saying ‘one mole of nitrogen’?
Q 30 – Dalton’s atomic theory is contradicted by the formula of sucrose (C12H22O11).’ Justify the statement.
Q 31 – Give an example to show law of conservation of mass applies to physical changes also.
Q 32 – Differentiate between the actual mass of a molecule and gram molecular mass.
Q 33 – What would be the difference in the composition of carbon dioxide in the two cases? State the associated law.
Q 34 – Does the solubility of a substance change with temperature? Explain with the help of an example.
Q 35 – What are ionic and molecular compounds? Give examples.
Q 36 – You are provided with a fine white coloured powder which is either sugar or salt. How would you identify it without tasting?