Question

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

Answer 1

Answer:

$0.875\text{ M}$

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:

$\frac{8.4}{40}\text{ = 0.21 mole}$

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:

$\frac{240}{1000}\text{ = 0.24 L}$

Finally, we have the molarity as:

$\frac{0.21}{0.24}\text{ = 0.875 mol/dm}^3$