Answer:
5.87 ×10¹⁹ molecules.
Explanation:
From the question given above, the following data were obtained:
Mass of C₆H₅NO₂ = 12 mg
Number of molecules of C₆H₅NO₂ =?
Next, we shall convert 12 mg to g. This can be obtained as follow:
1 mg = 10¯³ g
Therefore,
12 mg = 12 mg × 10¯³ g / 1 mg
12 mg = 0.012 g
Next, we shall determine the mass of 1 mole of C₆H₅NO₂. This can be obtained as follow:
1 mole of C₆H₅NO₂ = (12×6) + (5×1) + 14 + (16×2)
= 72 + 5 + 14 + 32
= 123 g
Finally, we shall determine the number of molecules present in 12 mg (i.e 0.012 g) of C₆H₅NO₂. This can be obtained as follow:
From Avogadro's hypothesis,
1 mole of C₆H₅NO₂ = 6.02×10²³ molecules
123 g of C₆H₅NO₂ = 6.02×10²³ molecules
Therefore,
0.012 g of C₆H₅NO₂ = 0.012 × 6.02×10²³ / 123
0.012 g of C₆H₅NO₂ = 5.87 ×10¹⁹ molecules.
Thus, 12 mg (i.e 0.012 g) of C₆H₅NO₂ contains 5.87 ×10¹⁹ molecules.
