Final answer:
The mass of phosphorus pentafluoride (PF5) that has the same number of fluorine atoms as 25.0 g of oxygen difluoride (OF2) is 43.8 g.
Step-by-step explanation:
The number of fluorine atoms in a molecule of phosphorus pentafluoride (PF5) is equal to the number of fluorine atoms in a molecule of oxygen difluoride (OF2). The molecular formula for PF5 indicates that there are 5 fluorine atoms. To find the mass of PF5 that has the same number of fluorine atoms as 25.0 g of OF2, we can use the concept of molar mass.
The molar mass of OF2 is 71.996 g/mol (16.00 g/mol for oxygen + 2(19.00 g/mol) for fluorine).
To find the mass of PF5, we need to know the molar mass. The molar mass of PF5 is 125.967 g/mol (30.97 g/mol for phosphorus + 5(19.00 g/mol) for fluorine).
Let's calculate the mass of PF5:
25.0 g OF2 × (125.967 g/mol / 71.996 g/mol) = 43.7997 g
Rounded to three significant figures: 43.8 g. Therefore, the mass of PF5 that has the same number of fluorine atoms as 25.0 g of OF2 is 43.8 g.