Question

What is the molarity of a solution that contains 80 g of NaOH in 4.0 liters of solution?

Answer 1

To find the molarity of a solution, you need to know the number of moles of solute (NaOH) and the volume of the solution.

First, you need to calculate the number of moles of NaOH:

Molar mass of NaOH = 22.99 g/mol (Na) + 16.00 g/mol (O) + 1.01 g/mol (H) = 39.99 g/mol

Number of moles of NaOH = mass of NaOH / molar mass of NaOH

= 80 g / 39.99 g/mol

= 2.001 mol (rounded to three decimal places)

Next, calculate the molarity of the solution:

Molarity (M) = moles of solute / volume of solution (in liters)

= 2.001 mol / 4.0 L

= 0.50025 M (rounded to five decimal places)

Therefore, the molarity of the solution is approximately 0.50025 M.

Answer 2

0.50 M

Step-by-step explanation:

The first step is to calculate the number of moles of NaOH in the solution using the formula:

`\boxed{\bold{moles = (mass)/(molar \:mass)}}`

The molar mass of NaOH is 40.00 g/mol (sodium: 22.99 g/mol, oxygen: 15.99 g/mol, hydrogen: 1.01 g/mol). So, the number of moles of NaOH in the solution is:

moles =
`\bold{ (80 g)/(40.00 g/mol )}`= 2.00 mol

The next step is to calculate the molarity of the solution using the formula:

`\boxed{\bold{molarity = (moles\: of \:solute)/(volume \:of\: solution \:in\: liters)}}`

In this case, the moles of solute (NaOH) is 2.00 mol and the volume of solution is 4.0 liters. So, the molarity of the solution is:

molarity =
`(2.00 mol)/(4.0 L )`= 0.50 M

Therefore, the molarity of the solution that contains 80 g of NaOH in 4.0 liters of solution is 0.50 M.