Question

When X molecules are removed from 200mg of N2O,2.89×10^-3 moles of N2O are left then X will be​

Answer 1

From Avagadro's Law we know that :-

1mole of any compound will always have :-

= 6.022 × 10²³ Molecules

Now,

Mass of $N_2O$ given is 200mg

Molecular mass of $N_2O$ is :-

$= 2(14) + 16 \\ \\ = 28 + 16 \\ \\ = 44g$

Number of moles of $N_2O$ given is :-

$moles = \frac{200 \times {10}^{( - 3)} }{44}$

Number of molecules given will be :-

$=\frac{200 \times {10}^{( - 3)} }{44} \times 6.022 \times {10}^{23}$

Now,

Moles left is :-

$= 2.89 \times {10}^{( - 3)} moles$

Molecules left will be :-

$2.89 \times {10}^{( - 3)} \times 6.022 \times {10}^{23}$

Now,

X will be the difference between the given and left molecules.

Thus

X will be :-

$= 6.022 \times {10}^{23}( \frac{0.2}{44} - 0.00289) \\ \\ \\ = 6.022 \times {10}^{23}(0.00165)molecules$

Therefore :-

X will be equal to :-

$\boxed{\red{\bold{\sf{0.00165\:N_A}}}}$