What is the molarity of a solution made by dissolving 18.9 g of
ammonium nitrate (NH4NO3) in
enough water to make 855 mL of
solution?
Molar Mass N: 14.01 g/mol
Molar Mass H: 1.008 g/mol
Molar Mass O: 16.00 g/mol

Molarity = 0.28 M

Explanation:

Given data:

Mass of NH₄NO₃ = 18.9 g

Volume of solution = 855 mL (855mL × 1 L/1000 mL = 0.855 L)

Molarity of solution = ?

Solution:

Number of moles of NH₄NO₃:

Number of moles = mass/molar mass

Number of moles = 18.9 g/ 80.043 g/mol

Number of moles = 0.24 mol

Molarity:

Molarity = number of moles of solute  / volume in L

Molarity = 0.24 mol /0.855 L

Molarity = 0.28 M