ANSWER
The mass of NaCl is 7.5 grams
EXPLANATION
Given that;
The volume of the solution is 0.625L
The molarity of the solution is 0.207 M
Follow the steps below to find the mass of NaCl
Step 1; Find the number of moles using the below formula
[tex]\begin{gathered} \text{ Molarity =}\frac{moles\text{ of solute}}{\text{ volume of solution}} \\ \end{gathered}[/tex][tex]\begin{gathered} \text{ 0.207 = }\frac{\text{ moles of solute}}{\text{ 0.625}} \\ \text{ cross multiply} \\ \text{ moles of solute = 0.207 }\times\text{ 0.625} \\ \text{ moles of solute = 0.1294 mole} \end{gathered}[/tex]
Step 2; Find the mass of NaCl using the below formula
[tex]\begin{gathered} \text{ mole = }\frac{\text{ mass}}{\text{ molar mass}} \\ \text{ cross multiply} \\ \text{ mass = mole }\times\text{ molar mass} \end{gathered}[/tex]
Recall, that the molar mass of NaCl is 58.44g/mol
[tex]\begin{gathered} \text{ mass = 0.1294 }\times\text{ 58.44} \\ \text{ mass = 7.5 grams} \end{gathered}[/tex]
Therefore, the mass of NaCl is 7.5 grams
