Question

If Nurse Antonio adds that 7 grams of NaCI to water to make 1 liter of solution, what is the molar concentration of the solution? Use dimensional analysis and show how you completed the unit conversion.

Answer 1

Given :

Nurse Antonio adds that 7 grams of NaCI to water to make 1 liter of solution.

To Find :

The molar concentration of the solution .

Solution :

Molecular mass of NaCl , $m=58.44\ g/mol$ .

Now , number of moles is given by :

$n=\dfrac{\text{Given weight}}{\text{Molecular Mass}}\\\\n=\dfrac{7}{58.44}\ mole\\\\n=0.12\ moles$

Molarity is given by :

$M=\dfrac{\text{Number of moles}}{\text{Volume ( in Liters)}}\\\\M=\dfrac{0.12}{1}\ M\\\\M=0.12\ M$

Hence , this is the required solution .