Express the concentration of a 2.0 M NaOH solution as a mass/volume percent.
8.0% (m/v) NaOH solution
How did you get that answer?
To express the concentration of a solution as a mass/volume percent, we need to determine the mass of the solute (NaOH) in a given volume of the solution.
The concentration of a solution is typically expressed in moles per liter (M). In this case, we have a 2.0 M (molar) NaOH solution. This means that there are 2.0 moles of NaOH present in every 1 liter (1000 mL) of the solution.
To find the mass of NaOH in a given volume, you'll need to know the density of the solution. Let's assume that the density of the 2.0 M NaOH solution is 1.20 g/mL.
Step 1: Calculate the molar mass of NaOH.
The molar mass of NaOH can be calculated by summing the atomic masses of each element: Na (sodium) has a molar mass of 22.99 g/mol, O (oxygen) has a molar mass of 16.00 g/mol, and H (hydrogen) has a molar mass of 1.01 g/mol.
Molar mass of NaOH = (22.99 g/mol) + (16.00 g/mol) + (1.01 g/mol) = 40.00 g/mol.
Step 2: Convert the moles of NaOH to grams.
Since the molar mass of NaOH is 40.00 g/mol, we can convert the moles to grams using this conversion factor.
2.0 moles NaOH x 40.00 g/mol = 80.00 grams NaOH.
Step 3: Calculate the volume/volume percent.
To calculate the mass/volume percent, we need to divide the mass of NaOH by the volume of the solution and multiply by 100.
Mass/volume percent = (mass of NaOH / volume of solution) x 100.
If the volume of the solution is 1000 mL (1 liter due to the 2.0 M concentration), we can calculate the mass/volume percent.
Mass/volume percent = (80.00 g / 1000 mL) x 100 = 8.00% (rounded to two decimal places).
So, the concentration of the 2.0 M NaOH solution expressed as a mass/volume percent is 8.00%.