To calculate the concentration of the solution in ppm (parts per million), you need to convert the molar concentration to ppm.
A ppm is a unit of concentration that represents the ratio of the mass of the solute to the mass of the solution, multiplied by one million.
Here's how you can calculate the concentration in ppm:
1. Calculate the mass of the solute (chlorophyll a) in grams.
Mass of chlorophyll a = molar concentration (mol/L) * volume of solution (L) * molecular weight (g/mol)
2. Calculate the mass of the solution in grams.
Mass of solution = volume of solution (L) * density of ethanol (g/mL) * 1000 (to convert mL to grams)
3. Calculate the ppm concentration.
ppm concentration = (mass of solute / mass of solution) * 1,000,000
Let's plug in the given values and calculate the concentration in ppm:
Given:
- Molar concentration = 0.435 M (already calculated in part A)
- Volume of solution (cuvette) = 1.3 cm = 0.0013 L (since 1 cm^3 = 0.001 L)
- Molecular weight of chlorophyll a = 893.49 g/mol
- Density of ethanol = 0.785 g/mL
Step 1: Calculate the mass of chlorophyll a
mass of chlorophyll a = 0.435 M * 0.0013 L * 893.49 g/mol = 0.501 g
Step 2: Calculate the mass of the solution
mass of solution = 0.0013 L * 0.785 g/mL * 1000 = 1.022 g
Step 3: Calculate the ppm concentration
ppm concentration = (0.501 g / 1.022 g) * 1,000,000 = 490,163 ppm
Therefore, the concentration of the solution in ppm is approximately 490,163 ppm.