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, you will need to follow these steps:
Step 1: Determine the molar mass of Potassium trioxalatochromate (III).
- Potassium (K) has a molar mass of 39.10 g/mol.
- Trioxalatochromate (III) consists of three oxalate ions (C2O4) and one chromium ion (Cr).
- The molar mass of oxalate ion (C2O4) is 88.02 g/mol.
- The molar mass of chromium (Cr) is 52.00 g/mol.
- So, the molar mass of Potassium trioxalatochromate (III) is calculated as:
Molar mass = (3 * Molar mass of C2O4) + (1 * Molar mass of Cr) + (1 * Molar mass of K)
Step 2: Calculate the moles of Potassium trioxalatochromate (III) needed.
- Concentration (M) = Moles (mol) / Volume (L)
- Rearranging the equation, Moles (mol) = Concentration (M) * Volume (L)
Since the given volume is in mL, we need to convert it to liters:
- 15 mL = 15/1000 L = 0.015 L
Now, substituting the values:
Moles (mol) = (1.10-3 M) * (0.015 L)
Step 3: Calculate the mass of Potassium trioxalatochromate (III) needed.
- Mass (g) = Moles (mol) * Molar mass (g/mol)
Now, substituting the values:
Mass (g) = (Moles obtained from Step 2) * (Molar mass obtained from Step 1)
2◇- To calculate the splitting energy of [Co(NO2)6] -3, we need to consider the given wavelength (364 nm) and the nature of the electronic transition. In this case, since there is a single band observed, we can assume it corresponds to the absorption of light by electrons undergoing a specific transition.
The splitting energy can be calculated using the formula:
Splitting energy (ΔE) = hc / λ
Where:
ΔE = Splitting energy in Joules (J)
h = Planck's constant (6.62607015 × 10^-34 J·s)
c = Speed of light (2.998 × 10^8 m/s)
λ = Wavelength of light (in meters)
First, we need to convert the given wavelength from nanometers (nm) to meters (m):
- 364 nm = 364 × 10^-9 m
Now, we substitute the values into the formula:
Splitting energy (ΔE) = (6.62607015 × 10^-34 J·s) * (2.998 × 10^8 m/s) / (364 × 10^-9 m)
3◇- To calculate the number of ions in the complex based on the conductivity value of 420 micro Siemens and a concentration of 1.10-3 M, we need to consider the relationship between conductivity (κ) and the concentration (C) of ions in solution.
The equation relating conductivity, concentration, and the number of ions (n) is:
κ = n × C × μ
Where:
κ = Conductivity in micro Siemens (μS)
n = Number of ions produced or consumed in the reaction
C = Concentration in M (Molar)
μ = Ion mobility in μS/cm²/mol
First, we need to convert the given conductivity value from micro Siemens to Siemens:
- 420 micro Siemens = 420 × 10^-6 Siemens
Now, we can substitute the values into the equation:
420 × 10^-6 Siemens = n × (1.10-3 M) × μ
To solve for n, divide both sides of the equation by [(1.10-3 M) × μ].