Question

how many molecules are there in 75 mg 0f NO2?​

Answer 1

Answer:

9.82 × 10^20 molecules

Explanation:

No. of moles (n) = Mass/ Molar Mass

:- n = 75×10^-3/ 46

:- n = 0.001630 moles.

1mole = 6.023 ×10²³ molecules

:- 0.001630 mole = X

x = 9.82 × 10^20 molecules.

Hope it helps.

Answer 2

Explanation:

$\large{ \pink{ \underline{ \bold{ \blue{Given :-}}}}}$

$\bold{Given \: mass \: of \: NO_2 = 75 g}$

$\bold{Atomic \: mass \: of \: O \: = 16 g}$

$\bold{Atomic \: mass \: of \: N = 14 \: g}$

$\bold{Molecular \: mass \: of \: NO_2 = 14 + 2 \times 16}$

$\bold{ = 14 + 32 = 46 \: g}$

$\bold{Number \: of \: molecules = 75 \times\frac{1}{46} \times 6.022 × 10^{23}}</p><p>$

$= 1.63 × 6.022 × 10^{23}$

$= 9.81586 \times {10}^{23}$

$\bold{Number \: of \: molecules \: 9.81586 \times 10^{23} \: molecules.}$

I hope it is helpful for you