What volume of ethanol must be diluted with water to prepare 768 mL of 0.873 M solution? The density of ethanol is given as 0.789 g/mL.
Answer in units of mL
To determine the volume of ethanol needed to prepare the solution, we need to use the formula:
Molarity (M) = moles of solute / volume of solution in liters
First, let's calculate the moles of ethanol needed.
Moles of ethanol = Molarity (M) x volume of solution (L)
Since we have the volume of the solution in milliliters, we need to convert it to liters:
Volume of solution (L) = 768 mL / 1000 mL/L
Now we can calculate the moles of ethanol:
Moles of ethanol = 0.873 M x (768 mL / 1000 mL/L)
Next, let's convert the moles of ethanol to grams using its molar mass. The molar mass of ethanol (C2H5OH) is 46.07 g/mol.
Grams of ethanol = Moles of ethanol x molar mass of ethanol
Now let's calculate the grams of ethanol needed:
Grams of ethanol = (0.873 M x (768 mL / 1000 mL/L)) x 46.07 g/mol
Since the density of ethanol is given as 0.789 g/mL, we can now determine the volume of ethanol by dividing the grams of ethanol by its density:
Volume of ethanol = Grams of ethanol / density of ethanol
Finally, let's calculate the volume of ethanol:
Volume of ethanol = ((0.873 M x (768 mL / 1000 mL/L)) x 46.07 g/mol) / 0.789 g/mL
Simplifying this expression will give you the answer in mL.
How many mols do you want? That's M x L = mols.
How many grams is that?
mols = grams/molar mass.
Then use mass = volume x densty and solve for volume .