First, you have to find the molar mass of sodium fluoride.
The equation for sodium fluoride is NaF (1 Na and 1 F). So, you look at the molar masses of Na and F on the periodic table (the numbers with the long decimals, under the Na or F symbol) and add them up.
Molar mass of Na = 22.990 grams/mole
Molar mass of F = 18.998 grams/mole
Molar mass of NaF = 22.990 + 18.998 = 41.988 grams/mol
So, multiply to find the number of grams:
[tex](4.5\ mol\ NaF)(\frac{41.998\ grams\ NaF}{1\ mol\ NaF}) = 188.946\ grams\ NaF[/tex]
