Class 11 Chemistry Half Yearly Question Paper

Class 11 Chemistry Half Yearly Question Paper

Time Allowed : 180 mins Maximum Marks : 70

	Section A
1	Molecular mass is the a) maximum of atomic masses of the elements present in a molecule b) minimum of atomic masses of the elements present in a molecule c) average of atomic masses of the elements present in a molecule d) sum of atomic masses of the elements present in a molecule	[1]
2	Which of the following represents the SI unit for heat capacity? a) J s^-1 b) J K^-1 mol^-1 c) J C^-1 d) J K^-1	[1]
3	The mass of an atom of nitrogen in amu is, a) 28/6.023×10²³ b) 1/6.023×10²³g c) 14/6.023×10²³ d) 14 amu	[1]
4	Find the energy of the photons which correspond to light of frequency 3 x 10¹⁵ Hz (Hint: h = Planck’s constant = 6.626 x 10^-34 Js). a) 1.308 x 10^-18 J b) 2.988 x 10^-18 J c) 0.988 x 10^-18 J d) 1.988 x 10^-18 J	[1]
5	Assertion (A): In case of isoelectronic ions the ionic size increases with the increase in atomic number. Reason (R): The greater the attraction of nucleus, greater is the ionic radius. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) Both A and R are false.	[1]
6	Which important property did Mendeleev use to classify the elements in his periodic table? a) Atomic weight b) Atomic number c) Atomic mass d) Melting point	[1]
7	Dietary calcium from various dairy and food products are essential for healthy bones. X – 90, a radioactive isotope, a component of waste generated by nuclear power facilities enters our body through ingestion. Our body mistakes X for Ca incorporating it into our bones which results in increased risk of leukaemia and other cancers. Which of the following could possibly be X? a) Rb b) Sr c) Po d) Th	[1]