Formula to Calculate Molarity (M)
Molarity is the concentration of a solution, which is defined as the number of moles of solute per liter of solution. The formula to calculate molarity is:
M = moles of solute / volume of solution in liters
Calculate Moles of NaCl
To calculate the moles of NaCl, we need to know its molecular weight. The molecular weight of NaCl is 58.44 g/mol. Therefore, the moles of NaCl can be calculated as:
moles of NaCl = mass of NaCl / molecular weight of NaCl
moles of NaCl = 3M x 1.25 g/ml / 58.44 g/mol
moles of NaCl = 0.064 mol
Calculate Volume of Solution in Liters
The volume of the solution can be calculated using the following formula:
volume of solution = mass of solution / density of solution
mass of solution = 3M x 1000 ml = 3000 g
volume of solution = 3000 g / 1.25 g/ml = 2400 ml = 2.4 L
Calculate Molarity
Now that we have calculated the moles of NaCl and the volume of the solution, we can calculate the molarity using the formula:
M = moles of solute / volume of solution in liters
M = 0.064 mol / 2.4 L = 0.027 M
Final Answer
The molarity of the 3M solution of NaCl is 0.027 M.