Question

How many number of moles of CO will be left when 2×10^21 molecules are removed from 0.28 g of CO

Answer 1

Answer:

Mass of CO = 0.28 g

The molar mass of CO = 28 g

∴ Total No. of moles of CO taken = mass / molar mass = 0.28 / 28 = 0.01 moles

No. of molecules removed from CO = 2 * 10²¹

We know,

1 mole of CO will have = 6.023 * 10²³ molecules of CO

∴ No. of moles in 2 * 10²¹ molecules of CO which was removed

= (2 * 10²¹) / (6.023 * 10²³)

= 0.332 * 10⁻²

= 0.00332 moles

Finally, the no. of CO left  

= (No. of moles of CO taken) – (no. of moles of CO removed)  

= 0.01 – 0.00332

= 0.00668 moles

= 6.68 * 10⁻³ moles

Hence,  6.68 * 10⁻³ moles of CO will be left.