Final answer:
To find the number of molecules of boron trichloride in 5.80 grams of the compound, divide the mass of the compound by its molar mass to find the number of moles, then use Avogadro's number to calculate the number of molecules.
Step-by-step explanation:
To find the number of molecules of boron trichloride in 5.80 grams of the compound, we need to convert the mass of the compound to moles and then use Avogadro's number to calculate the number of molecules.
The molar mass of boron trichloride (BCl3) is 117.17 g/mol (10.81 g/mol for boron and 35.45 g/mol for chlorine, multiplied by 3).
First, we calculate the number of moles by dividing the mass of the compound by its molar mass:
Number of moles of BCl3 = 5.80 g / 117.17 g/mol
= 0.0495 mol
Finally, we use Avogadro's number (6.022 x 1023 molecules/mol) to calculate the number of molecules:
Number of molecules of BCl3 = 0.0495 mol x 6.022 x 1023 molecules/mol
= 2.98 x 1022 molecules