What is the molarity of a solution in which 58 g of NaCl are dissolved in 1.0 L of solution?
To determine the molarity of a solution, we need to know two pieces of information: the amount of solute in moles and the volume of the solution in liters.
First, let's convert the mass of NaCl to moles. We can do this by using the molar mass of NaCl, which is the sum of the atomic masses of sodium (Na) and chlorine (Cl). The atomic mass of sodium is 22.99 g/mol, and the atomic mass of chlorine is 35.45 g/mol.
1. Calculate the molar mass of NaCl:
Molar mass of NaCl = (1 × atomic mass of Na) + (1 × atomic mass of Cl)
= (1 × 22.99 g/mol) + (1 × 35.45 g/mol)
= 22.99 g/mol + 35.45 g/mol
= 58.44 g/mol
2. Convert the mass of NaCl to moles:
Moles of NaCl = Mass of NaCl / Molar mass of NaCl
= 58 g / 58.44 g/mol
≈ 0.9934 mol
Now that we have the moles of NaCl, we can calculate the molarity of the solution.
3. Molarity (M) is defined as moles of solute per liter of solution:
Molarity = Moles of solute / Volume of solution
In this case, the moles of solute is 0.9934 mol, and the volume of the solution is 1.0 L.
Molarity = 0.9934 mol / 1.0 L
≈ 0.9934 M
Therefore, the molarity of the solution is approximately 0.9934 M.
mols NaCl = grams/molar mass
M = mols/L