Multiple Choice Questions
Multiple Choice Questions
Q.1. 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.2. In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always :
(a) 1: 8
(b) 2 : 8
(C) 1: 16
(d) 3 : 16
Q.3. Which of the following postulates of Dalton’s atomic theory is challenged by the next generation scientists?
(a) All matter is made of very tiny particles called atoms.
(b) Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction.
(c) Atoms combine in the ratio of small whole numbers to form compounds.
(d) Atoms of a given element are identical in mass and chemical properties.
Q.4. Which of the following represents 14 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.5. The symbols of calcium, carbon and copper are:
(a) Ca, C, Co
(b) Ca, C, Cu
(c) Ca, C, Cr
(d) Ca, Cr, Cu
Q.6. The unit accepted for taking mass of atom and molecule is :
(a) gram
(b) milligram
(c) molecular mass unit
(d) atomic mass unit
Q.7. 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 CH4
Q.8. Which of the following contains maximum number of molecules ?
(a) 1 g CO2
(b) 1 g N2
(c) 1 g H2
(d) 1 g CH4
Q.9. The molecule having an atomicity of 4 is :
(a) Sulphur molecule
(b) Ozone molecule
(c) Phosphorus molecule
(d) Methane molecule
Q.10. The chemical symbol for nitrogen gas is :
(a) Ni
(b) N2
(c) N+
(d) N
Q.11. The chemical symbol for sodium is :
(a) So
(b) Sd
(c) NA
(d) Na
Q.12. Which of the following correctly represents 360 g of water ?
(i) 2 moles of H2O
(ii) 20 moles of water
(iii) 6.022 x 1023 molecules of water
(iv) 1.2044 x 1025 molecules of water
(a) (i)
(b) (i) and (iv)
(c) (ii) and (iii)
(d) (ii) and (iv)
Q.13. Which of the following statements is not true about an atom ?
(a) Atoms are not able to exist independently
(b) Atoms are the basic units from which molecules and ions are formed
(c) Atoms are always neutral in nature
(d) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.
Q.14. One mole of H₂0 means:
(i) 18 g of H2O
(ii) 6.022 x 1023 molecules of H2O
(iii) 180 g of H2O
(iv) 1.8 g of H2O
(a) Both (i) and (ii) are correct
(b) Both (ii) and (iii) are correct
(c) Only (1) is correct
(d) Both (iii) and (iv) are correct
Q.15. A molecule can be defined as the :
(a) A group of two or more atoms that are chemically bonded together.
(b) A smallest particle of an element or a compound that is capable of an independent existence and shows all the properties of that substance.
(c) Substance which is formed by the combination of atoms of the same element or of different elements.
(d) All of these are correct.
Q.16. Which of the following will have maximum mass ?
(a) 1022 molecules of H2O
(b) 1022 molecules of NH3
(c) 2 moles of NH3
(d) 2 moles of H2O
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