WBCS.LIVE practice question

If number of molecules present in 9 g of water is n, then number of molecules present in 44 g of carbon-di-oxide is

Solve this multiple-choice question and check the correct answer with its explanation below.

Answer options

  1. n
  2. 2n
  3. n2
  4. 3n

Correct answer and explanation

Correct answer: 2n

Explanation: āœ… Correct Answer: B) 2n šŸ“š Explanation: The molecular weight of water (H2O) is 18g, so 9g is 0.5 moles. The molecular weight of carbon dioxide (CO2) is 44g, so 44g is exactly 1 mole. Since 0.5 moles contain 'n' molecules, 1 full mole will contain twice that amount, which is '2n'. This is based on Avogadro's law regarding the number of molecules in a mole.