Question

Determine the molarity of a solution that is made by dissolving 20.0 g of ammonium nitrate (NH4NO3) in enough water to make 125.0 mL of solution.

Answer 1

To determine the molarity of the ammonium nitrate (NH4NO3) solution, we need to use the formula:

Molarity (M) = (number of moles of solute) / (volume of solution in liters)

First, we need to calculate the number of moles of NH4NO3 in the solution:

Calculate the molar mass of NH4NO3:
NH4NO3 = (1 x 14.01 g/mol) + (4 x 1.01 g/mol) + (3 x 16.00 g/mol)
NH4NO3 = 80.04 g/mol

Convert the mass of NH4NO3 to moles:
moles of NH4NO3 = mass / molar mass
moles of NH4NO3 = 20.0 g / 80.04 g/mol
moles of NH4NO3 = 0.2499 mol

Next, we need to convert the volume of the solution from milliliters (mL) to liters (L):

volume of solution = 125.0 mL / 1000 mL/L
volume of solution = 0.125 L

Now we can calculate the molarity of the solution:

Molarity (M) = moles of solute / volume of solution in liters
Molarity (M) = 0.2499 mol / 0.125 L
Molarity (M) = 1.9992 M (rounded to four significant figures)

Therefore, the molarity of the ammonium nitrate solution is approximately 1.9992 M