A solution of iron(III) thiocyanate was produced by dissolving 7.98 milligrams solid iron(III) thiocyanate in enough water to produce a 100.00 mL solution. What is the concentration, in molarity, of the solution?
mols Fe = grams Fe/atomic mass Fe.
Then M = mols Fe/L solution.
3.46896 x 10e-5
To find the concentration of the solution in molarity (M), we need to know the number of moles of iron(III) thiocyanate and the volume of the solution.
First, let's calculate the number of moles of iron(III) thiocyanate using its molar mass.
The molar mass of iron(III) thiocyanate (Fe(SCN)₃) can be calculated by adding up the molar masses of its components: iron (Fe), sulfur (S), carbon (C), and nitrogen (N).
Fe: atomic mass = 55.85 g/mol
S: atomic mass = 32.07 g/mol
C: atomic mass = 12.01 g/mol
N: atomic mass = 14.01 g/mol
The total molar mass of Fe(SCN)₃ is:
(1 x Fe) + (3 x S) + (3 x C) + (3 x N) = 55.85 + 3(32.07) + 3(12.01) + 3(14.01) = 55.85 + 96.21 + 36.03 + 42.03 = 230.12 g/mol
Now, let's calculate the number of moles of Fe(SCN)₃:
moles = mass / molar mass
moles = 7.98 mg / 230.12 g/mol
Note: We convert the mass from milligrams (mg) to grams (g) before dividing by the molar mass.
moles = 0.00798 g / 230.12 g/mol
moles = 0.000034700 mol (rounded to 6 decimal places)
Next, we need to determine the volume of the solution in liters. We are given that the volume is 100.00 mL. We need to convert this to liters by dividing by 1000 (since there are 1000 mL in 1 L).
volume (in liters) = 100.00 mL / 1000
volume = 0.1000 L
Finally, we can calculate the concentration (molarity) using the formula:
Molarity (M) = moles / volume
Molarity = 0.000034700 mol / 0.1000 L
Molarity = 0.347 M (rounded to 3 decimal places)
Therefore, the concentration of the iron(III) thiocyanate solution is approximately 0.347 M.