Question

When 10²¹ molecules are removed from x mg of CO₂(g), then 2.4 × 10^–3 moles of CO₂ are left. Calculate the value of x. [Take \(\Rightarrow\) NA = 6 × 10²³]

Answer 1

Answer is :179

Number of moles of CO₂ removed = \(\frac{10^{21}}{6 \times 10^{23}}\) \(= 0.167 \times 10^{-2} mol\)

Number of moles of CO₂ left = 2.4 × 10^–3 mol 

Total moles = 2.4 × 10^–3 + 1.67 × 10^–3 = 4.07 × 10^–3 mol 

Mass of CO₂ present = 4.07 × 44 × 10^–3 = 179 × 10^–3 g = 179 mg