What is the molar concentration (M= molarity) of a solution prepared by dissolving 50 g of NaCl in 750ml of water?
To be technical about it, the molarity can't be calculated. The definition of molarity is moles/L of SOLUTION. Placing NaCl in 750 mL water will NOT produce 750 mL of solution; the final solution will be greater than 750 mL.
I will assume the author of the problem MEANT to write soln instead of water.
mol NaCl = grams/molar mass
Then M = moles/L soln (0.750 L)
To determine the molar concentration (M) of a solution, you need to calculate the number of moles of solute (NaCl) and divide it by the volume of solution in liters. Here's how you can do it step by step:
1. Convert the mass of NaCl from grams to moles using its molar mass. The molar mass of NaCl is the sum of the atomic masses of sodium (Na) and chlorine (Cl), which is approximately 58.44 g/mol.
Moles of NaCl = mass of NaCl / molar mass of NaCl
= 50 g / 58.44 g/mol
2. Calculate the volume of the solution in liters. As given, the solution is prepared by dissolving 50 g of NaCl in 750 mL of water.
Volume of solution = 750 mL = 750 cm³
= 750 cm³ x (1 mL/1 cm³) x (1 L/1000 mL)
= 0.75 L
3. Finally, divide the moles of NaCl by the volume of the solution in liters to determine the molar concentration.
Molar concentration (M) = moles of NaCl / volume of solution
= (50 g / 58.44 g/mol) / 0.75 L