Question

Question #fa66b

Answer 1

`1.76 * 10^(25)`

Explanation:

For starters, you know that `1` mole of boron trifluoride contains

• one mole of boron, `1 xx "B"`
• three moles of fluorine, `3 xx "F"`

This implies that your sample of boron trifluoride will contain

`9.72 color(red)(cancel(color(black)("moles BF"_3))) * "3 moles F"/(1color(red)(cancel(color(black)("mole BF"_3)))) = "29.16 moles F"`

Now, `1` mole of any element contains `6.022 * 10^(23)` atoms of that element `->` this is known as Avogadro's constant.

You can thus say that your sample will contain

`29.16 color(red)(cancel(color(black)("moles F"))) * (6.022 * 10^(23)color(white)(.)"atoms of F")/(1color(red)(cancel(color(black)("mole F")))) = color(darkgreen)(ul(color(black)(1.76 * 10^(25)color(white)(.)"atomf of F")))`

The answer is rounded to three sig figs, the number of sig figs you have for the number of moles of boron trifluoride.