What mass of bromine trifluoride, BrF 3, has the same number of fluorine atoms as 25.0 g of oxygen difluoride, OF2?

42.29 g of BrF₃.

Explanation:

Molar mass of OF2 = 16 + (2 * 19)

= 54 g/mol

Number of moles of OF₂ = mass / molar mass

= 25/54

= 0.46 mol.

Number of OF₂ molecules = number of moles * avogadros constant

= 0.46 * 6.022 x 10²³

= 2.8 x 10^23 molecules of OF2.

Since each OF₂ molecule has 2 Fluorine atoms,

Number of Fluorine atoms in 25.0 g of OF₂ = 2 x 2.8 x 10²³

= 5.576 x 10²³ atoms of Fluorine.

Since 1 BrF₃ molecule has 3 Fluorine atoms,

number of BrF₃ molecules = Number of Fluorine atoms / 3

= 5.576 x 10²³ / 3

= 1.8587 x 10²³ molecules of BrF₃.

Number of moles of BrF₃ = number of molecules of BrF₃ / Avogadros constant

= (1.8587 x 10²³) / (6.022 x 10²³)

= 0.30865 moles of BrF₃.

Molar mass of BrF₃ = 80 + (19 * 3)

= 137 g/mol

mass of BrF₃ = number of moles * molar mass

= 0.30865 * 137

= 42.29 g of BrF₃.