to find molarity use the following formula
molarity= moles/ liters
first, we need to calculate the moles using the grams of NH₃. remember to convert grams to moles, you need the molar mass of the molecule which you can determine by adding the mass of each atom
molar mass of NH₃ = 14.0 + (3 x 1.01)= 17.03 g/ mol
now, let convert grams to moles
17.0 g (1 mol/ 17.03 grams)= .998 moles NH₃
now, we can plug in these values to solve for molarity
molarity= 0.998 mol/ 2.0 Liters= 0.50 M (the answer is a)
