NEET Chemistry - New - Some Basic Concepts of Chemistry

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Question - 1

Suppose the elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mole of XY2 weighs 10 g and 0.05 mole of X3Y2 weighs 9 g, the atomic weights of X and Y are:

  • A 40, 30
  • B 60, 40
  • C 20, 30
  • D 30, 20

Question - 2

An element, X has the following isotopic composition 200X : 90%, 199X: 8.0%, 202X: 2.0%. The weighted average atomic mass of the naturally occurring element X is closest to :

  • A 201 amu
  • B 202 amu
  • C 199 amu
  • D 200 amu

Question - 3

Specific volume of cylindrical virus particle is 6.02 x 10-2 cc/g, whose radius and length are 7 Å and 10 Å respectively. If NA = 6.023 X 1023, find molecular weight of virus:

  • A 15.4 kg/mol
  • B 1.54 x 104 kg/mol
  • C 3.08 x 104 kg/mol
  • D 3.08 x 103 kg/mol

Question - 4

The number of significant figures for the three numbers 161 cm, 0.161 cm, 0.0161 cm are:

  • A 3, 4 and 5 respectively
  • B 3, 4 and 4 respectively
  • C 3, 3 and 4 respectively
  • D 3, 3, and 3 respectively

Question - 5

In the final answer of the expression  \(\frac { (29.2-20.2)\quad (1.79\times { 10 }^{ 5 }) }{ 1.37 } \)  The number of significant figures is :

  • A 1
  • B 2
  • C 3
  • D 4

Question - 6

Boron has two stable isotopes, 10B (19%) and 11B (81%). Calculate average atomic weight of boron in the periodic table:

  • A 10.8
  • B 10.2
  • C 11.2
  • D 10.0

Question - 7

In which case is the number of molecules of water maximum?

  • A 18 mL of water
  • B 0.18 g of water
  • C 0.00224 L of water vapours at 1 atm and 273 K
  • D 10-3 mol of water

Question - 8

The number of water molecules is maximum in:

  • A 1.8 gram of water
  • B 18 gram of water
  • C 18 moles of water
  • D 18 molecules of water

Question - 9

The number of atoms in 0.1 mole of a triatomic gas is (NA= 6.023 X 1023mol-1) :

  • A 6.026 x 1022
  • B 1.806 x 1023
  • C 3.600 x 1023
  • D 1.800 x 1022

Question - 10

Volume occupied by one molecule of water (density = 1 g cm-3) is :

  • A 9.0 x 10-23cm3
  • B 6.023 x 10-23cm3
  • C 3.0 x 10-23cm3
  • D 5.5 x 10-23cm3