Question

What is the mass required to make a 311 mL of 7.5M NaCl solution?

Answer 1

`136.31\text{ g}`

Step-by-step explanation:

Here, we want to get the mass required to make the given volume

To get this we need to get the number of moles

To get the number of moles, we have to multiply the volume by the molarity

Mathematically, we have that as:

`\begin{gathered} number\text{ of moles = volume }*\text{ molarity} \\ \end{gathered}`

The volume can be converted to liters by dividing by 1000

So we have the volume as 311/1000 = 0.311 L

Thus, we have the number of moles as:

`number\text{ of moles = 0.311 }*\text{ 7.5 = 2.3325 moles}`

To get the mass, we have to multiply the number of moles by the molar mass

The molar mass of NaCl is 58.44 g/mol

Thus, we have the mass as:

`2.3325\text{ }*\text{ 58.44= 136.31 g}`