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KVPY2019ChemistrySome Basic Concepts of Chemistry

The number of water molecules in 250   m   L of water is closest to [Given, density of water is 1 . 0   g   m   L - 1 ; Avogadro's number = 6 . 023 × 10 23

Options

  1. A83 . 6 × 10 23
  2. B139 × 10 23
  3. C1 . 5 × 10 23
  4. D336 × 10 23

Correct answer

A. 83 . 6 × 10 23

Step-by-step solution

Given, density of water = 1 . 0   g   m   L - 1 volume of water = 250   m   L ∴ Mass of water = density × volume = 1 . 0 × 250 = 250   g 18   g of water contains = 6 . 023 × 10 23 molecules ∴ 250   g of water contains = 6 . 023 × 10 23 18 × 250 = 83 . 65 × 10 23 molecules

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