Final answer:
To find the moles of sodium chloride in a 619 mL solution with a molarity of 2.69 M, convert the volume to liters and then multiply by the molarity. There are 1.66 moles of sodium chloride in the solution.
Step-by-step explanation:
To calculate the number of moles of sodium chloride in a 619 mL solution with a molarity of 2.69 M, we need to use the definition of molarity as moles of solute per liter of solution. Since molarity (M) is given in moles per liter (mol/L), and the volume is given in milliliters (mL), we first need to convert the volume to liters (L). We can do this by dividing the volume in milliliters by 1000 to get liters:
Volume in liters = 619 mL / 1000 = 0.619 L
Next, we use the molarity of the solution to find the number of moles of sodium chloride:
Moles of NaCl = Molarity × Volume (in L) = 2.69 M × 0.619 L = 1.66 mol
Therefore, the answer to the question is A. 1.66 mol of sodium chloride are present in 619 mL of a 2.69 M solution.