describe how you would prepare 500 mL 0.250 M ethylene glycol (MW=62.07) from concentrated 31% (w/w) solution that has a density of 1.0350 g/mL
See you post above.
To prepare a 0.250 M ethylene glycol solution with a volume of 500 mL, we will first need to calculate the amount of ethylene glycol required.
1. Calculate the concentration in moles per liter (Molarity):
0.250 M = 0.250 moles / 1 liter
2. Calculate the number of moles required for 500 mL:
Moles = Molarity x Volume
Moles = 0.250 moles/L x 0.500 L
Moles = 0.125 moles
3. Convert the moles of ethylene glycol to grams using its molar mass:
Mass = Moles x Molar Mass
Mass = 0.125 moles x 62.07 g/mole
Mass = 7.75875 grams
Now, we need to find the amount of concentrated solution needed to obtain 7.75875 grams of ethylene glycol.
4. Calculate the mass of concentrated solution required:
Mass of concentrated solution = Mass of ethylene glycol / (Density x %w/w)
Mass of concentrated solution = 7.75875 grams / (1.0350 g/mL x 31/100)
Mass of concentrated solution = 7.75875 grams / 0.32085
Mass of concentrated solution = 24.1688 grams
This means you need 24.1688 grams of the concentrated 31% (w/w) ethylene glycol solution.
To prepare the final solution:
5. Measure 24.1688 grams of the concentrated solution using a balance.
6. Add the measured concentrated solution to a volumetric flask.
7. Add distilled water to the volumetric flask until the total volume reaches 500 mL. Ensure thorough mixing to achieve a homogeneous solution.
By following these steps, you will be able to prepare a 500 mL 0.250 M ethylene glycol solution from the given concentrated solution.