Question

What is the molarity of a solution that contains 8.4 g NaOH in 240.0 mL of solution?

Answer 1

The molarity of the solution is 0.875 M.

Step-by-step explanation:

To find the molarity of a solution, we need to know the amount of solute (in moles) and the volume of the solution (in liters). First, convert the mass of NaOH to moles by using its molar mass (40.0 g/mol):

8.4 g NaOH ÷ 40.0 g/mol = 0.21 mol NaOH

Next, convert the volume of the solution to liters:

240.0 mL ÷ 1000 mL/L = 0.240 L

Finally, divide the number of moles of NaOH by the volume of the solution to calculate the molarity:

Molarity = 0.21 mol NaOH ÷ 0.240 L = 0.875 M

Answer 2

`0.875\text{ M}`

Explanation;

Here, we want to calculate the molarity of the solution

To calculate the molarity, we use the following formula:

`molarity\text{ = }\frac{number\text{ of moles}}{volume}`

To calculate the number of moles, we have to divide the mass by the molar mass

The molar mass of sodium hydroxide is 40 g/mol

Thus, we have the number of moles as:

`(8.4)/(40)\text{ = 0.21 mole}`

The volume to use would be in L

To get this, we divide the given volume by 1000

Thus, we have the volume in liters as:

`(240)/(1000)\text{ = 0.24 L}`

Finally, we have the molarity as:

`(0.21)/(0.24)\text{ = 0.875 mol/dm}^3`