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Question: $2.8 \times 10^{-3}$ mol of CO$_2$ is left after removing $10^{21}$ molecules form its 'x' mg sample...

2.8×10−32.8 \times 10^{-3} mol of CO2_2 is left after removing 102110^{21} molecules form its 'x' mg sample. The mass of CO2_2 take initially is Given: NA_A = 6.02×10236.02 \times 10^{23} mol−1^{-1}

Answer

196 mg

Explanation

Solution

Solution Explanation:

  1. Calculate moles of CO₂ removed:
      Moles removed = (10²¹) ÷ (6.02×10²³) ≈ 1.66×10⁻³ mol
  2. Total initial moles = moles left + moles removed
      = 2.8×10⁻³ mol + 1.66×10⁻³ mol = 4.46×10⁻³ mol
  3. Mass of CO₂ initially = (total moles) × (Molar mass of CO₂)
      = 4.46×10⁻³ mol × 44 g/mol ≈ 0.196 g = 196 mg