Calculate the molality and molarity of 16% aqouos methanol by volume density 0.9g/ml
To calculate the molality and molarity of a solution, we need to know the amount of solute (methanol) and the amount of solvent (water). In this case, we have 16% aqueous methanol by volume, which means that 16 mL of methanol is present in every 100 mL of the solution.
First, let's calculate the mass of methanol present in 100 mL (0.1 L) of the solution using the density given.
Mass = Volume x Density
= 0.1 L x 0.9 g/mL
= 0.09 g
Next, we need to convert the mass of methanol to moles. To do this, we'll use the molar mass of methanol, which is approximately 32 g/mol.
Moles = Mass / Molar mass
= 0.09 g / 32 g/mol
= 0.0028125 mol
Now, let's calculate the molality. Molality is defined as the number of moles of solute divided by the mass of the solvent (in kg).
Molality = Moles of solute / Mass of solvent
= 0.0028125 mol / 0.1 kg
= 0.028125 mol/kg
Finally, let's calculate the molarity. Molarity is defined as the number of moles of solute divided by the volume of the solution (in liters).
Molarity = Moles of solute / Volume of solution
= 0.0028125 mol / 0.1 L
= 0.028125 mol/L
Therefore, the molality of the 16% aqueous methanol solution is 0.028125 mol/kg, and the molarity is also 0.028125 mol/L.