1◇- You are asked to prepare 1.10-3 M 15 mL Potassium tri oxalato chromate (III) solution for conductivity measurement studies. Describe the preparation of the solution by making the necessary calculations?
2◇- Calculate the splitting energy of [Co (NO2) 6] -3 since 364 nm has a single band?
3◇- 420 micro Siemens value is read in the conductivity device for the complex prepared at the concentration of 1.10-3 M. Calculate the number of ions of the complex?
1◇ To prepare a 1.10-3 M 15 mL Potassium trioxalatochromate(III) solution, we need to calculate the amount of the compound needed.
Step 1: Determine the molar mass of Potassium trioxalatochromate(III). The formula for this compound is K3[Cr(C2O4)3]. It consists of three potassium ions (K+), one chromium ion (Cr3+), and three trioxalato ions (C2O4-). The molar mass can be calculated as follows:
Molar mass of K3[Cr(C2O4)3] = (3 * Molar mass of K+) + (1 * Molar mass of Cr3+) + (3 * Molar mass of C2O4-)
Note: The molar mass of each element can be found on the periodic table.
Step 2: Calculate the amount of Potassium trioxalatochromate(III) needed in moles.
Moles = concentration (in M) * volume (in L)
Moles = 1.10-3 M * 0.015 L
Step 3: Convert moles to grams using the molar mass of Potassium trioxalatochromate(III).
Grams = Moles * Molar mass
Now that you have the mass of the compound, you can prepare the solution by dissolving it in the appropriate volume of solvent, usually water or a specific solvent mentioned in the experiment procedure.
2◇ To calculate the splitting energy of [Co(NO2)6]-3, you need to use the equation:
ΔE = hc/λ
Where:
ΔE is the splitting energy in Joules (J).
h is the Planck constant (6.626 x 10^-34 J·s).
c is the speed of light (3.0 x 10^8 m/s).
λ is the wavelength of light in meters (m).
Given that a single band is observed at a wavelength of 364 nm (1 nm = 1 x 10^-9 m), you can substitute these values into the equation to calculate the splitting energy.
ΔE = (6.626 x 10^-34 J·s * 3.0 x 10^8 m/s) / (364 x 10^-9 m)
3◇ To calculate the number of ions in the complex, we can use the equation:
Conductivity (in Siemens/m) = Conductivity constant * concentration * number of ions
Given the conductivity value of 420 micro Siemens (1 Siemens = 10^6 micro Siemens), you can convert it to Siemens/m and substitute it into the equation along with the concentration of the complex (1.10-3 M).
420 x 10^-6 Siemens/m = conductivity constant * 1.10-3 M * number of ions
Solve for the number of ions:
number of ions = (420 x 10^-6 Siemens/m) / (conductivity constant * 1.10-3 M)