How many grams of sodium chloride, NaCl (fw 58.44), are required to prepare exactly 200 mL of a solution that is 600 ppm in sodium ions?
To calculate the number of grams of sodium chloride (NaCl) required to prepare the given solution, we need to follow these steps:
Step 1: Calculate the molar mass of sodium chloride.
The molar mass of NaCl is given as 58.44 g/mol.
Step 2: Calculate the molarity of the solution.
Since the solution is 600 ppm in sodium ions, we can assume that the concentration of sodium ions is 600 mg/L (parts per million means milligrams per liter).
To convert the concentration from mg/L to moles/L (Molarity), we need to divide by the molar mass of sodium (Na = 22.99 g/mol):
600 mg/L ÷ 22.99 g/mol = 26.1 mmol/L
Step 3: Convert the molarity to moles/mL (Millimoles per mL) since we need to prepare 200 mL of the solution.
26.1 mmol/L × 200 mL = 5220 mmol
Step 4: Convert the moles to grams by multiplying with the molar mass of NaCl.
5220 mmol × 58.44 g/mol = 304,444.8 mg
Therefore, to prepare exactly 200 mL of a solution that is 600 ppm in sodium ions, you would need 304.445 grams of sodium chloride (NaCl).