Question

Question #1ff7e

Answer 1

A 4.50-mole sample of `"SnF"_2"` will contain 171 g of fluoride ions.

Explanation:

The formula unit for the ionic compound stannous fluoride `("SnF"_2)` indicates that there are two moles of fluoride ions `("F"^(-))` in one mole of stannous fluoride.

`4.50color(red)cancel(color(black)("mol SnF"_2))xx(2"mol F"^(-))/(1color(red)cancel(color(black)("mol SnF"_2)))="9.00 mol F"^(-)`

Multiply the mol `"F"^(-)` by its molar mass: `"18.998 g/mol"`. (The atomic weight of F to five sig figs on the periodic table in g/mol.)

`9.00color(red)cancel(color(black)("mol F"^(-)))xx(18.998"g F"^(-))/(1color(red)cancel(color(black)("mol F"^(-))))="171 g F"^(-)` (rounded to three sig figs)