Question

How many moles of ammonium nitrate are present in `"8.047 g"` of this substance?

Answer 1

That much ammonium nitrate contains `"0.1005 moles"`.

When you are asked to convert either grams to moles, or moles to grams, always think molar mass.

A compound's molar mass represents the weight of 1 mole of that respective compound. You can either look up the molar mass of ammonium nitrate, `NH_4NO_3`, or add the molar masses of the atoms that comprise it.

Since ammonium nitrate's molar mass represents the mass of 1 mole, you can use it to determine how many moles you correspond to that many grams

`"molar mass" = "m"/"n" => "n" = "m"/"molar mass"`

In your case, ammonium nitrate's molar mass is 80.052 g/mol, which means that

`n = ("8.047"cancel("g"))/("80.052"cancel("g")/"mol") = "0.1005 moles"` `NH_4NO_3`