Calculate the concentrations of each of the ions in 0.25 M Fe(NO3)2.
a) [Fe2+], M
b) [NO3-], M
Wouldn't [Fe^2+] = 0.25M?
Wouldn't [NO3^-] be just twice that?
To calculate the concentrations of each of the ions in a solution, we need to determine the number of moles of each ion present and then divide by the total volume of the solution.
In the case of 0.25 M Fe(NO3)2, we can start by breaking down the compound into its constituent ions: Fe2+ and NO3-. The 2 in Fe(NO3)2 tells us that there are two moles of Fe2+ ions for every one mole of the compound.
a) To calculate the concentration of Fe2+ ions, we need to determine the number of moles of Fe2+ ions present. Since the molarity is given as 0.25 M, it means there are 0.25 moles of Fe(NO3)2 in 1 liter of solution. Since there are two moles of Fe2+ ions in one mole of the compound, we multiply the number of moles of Fe(NO3)2 by 2 to get the number of moles of Fe2+ ions:
0.25 moles Fe(NO3)2 * 2 moles Fe2+/1 mole Fe(NO3)2 = 0.5 moles Fe2+
Now, we divide the number of moles of Fe2+ ions by the volume of the solution to calculate the concentration:
Concentration of Fe2+ = 0.5 moles Fe2+ / 1 L = 0.5 M
Therefore, the concentration of Fe2+ ions in 0.25 M Fe(NO3)2 is 0.5 M.
b) The concentration of NO3- ions can be calculated in a similar manner. Since there are three moles of NO3- ions in one mole of Fe(NO3)2, we multiply the number of moles of Fe(NO3)2 by 3 to get the number of moles of NO3- ions:
0.25 moles Fe(NO3)2 * 3 moles NO3-/1 mole Fe(NO3)2 = 0.75 moles NO3-
Dividing the number of moles of NO3- ions by the volume of the solution gives us the concentration:
Concentration of NO3- = 0.75 moles NO3- / 1 L = 0.75 M
Therefore, the concentration of NO3- ions in 0.25 M Fe(NO3)2 is 0.75 M.