Calculate the concentration of nitrate ions, NO3- , in mol dm-3, of a solution made by dissolving 2.5000 g of ferric nitrate nonahydrate in water to give 2.000 L of solution.
You must mean monohydrate.
moles = 2.50g/molar mass Fe(NO3)3.H2O
M = moles/L soln.
To calculate the concentration of nitrate ions, we need to do the following steps:
1. Determine the moles of ferric nitrate nonahydrate (Fe(NO3)3·9H2O) in the given mass.
First, we need to find the molar mass of ferric nitrate nonahydrate:
Fe(NO3)3·9H2O
Fe: 1 atom x 55.85 g/mol = 55.85 g/mol
N: 3 atoms x 14.01 g/mol = 42.03 g/mol
O: 9 atoms x 16.00 g/mol = 144.00 g/mol
H2O: 9 molecules x (2 atomic H x 1.01 g/mol + 16.00 g/mol) = 162.18 g/mol
Total molar mass of ferric nitrate nonahydrate:
55.85 g/mol + 42.03 g/mol + 144.00 g/mol + 162.18 g/mol = 404.06 g/mol
Now we can calculate the moles of ferric nitrate nonahydrate:
moles = mass / molar mass
moles = 2.5000 g / 404.06 g/mol
2. Determine the moles of nitrate ions (NO3-) in the solution.
In ferric nitrate nonahydrate (Fe(NO3)3·9H2O), there are three nitrate ions per formula unit.
moles of nitrate ions = moles of ferric nitrate nonahydrate x 3
3. Calculate the concentration of nitrate ions.
Concentration (in mol/dm³) = moles of nitrate ions / volume of solution (in dm³)
The volume of the solution is given as 2.000 L, which is equal to 2.000 dm³.
Concentration of nitrate ions (NO3-) = moles of nitrate ions / volume of solution
Now, plug in the values and calculate the concentration.